Climate change and climate policy implications for the ...

Climate change and climate policy implications for the Australian avocado industry David Putland Growcom Project Number: AV09003

AV09003 This report is published by Horticulture Australia Ltd to pass on information concerning horticultural research and development undertaken for the avocado industry. The research contained in this report was funded by Horticulture Australia Ltd with the financial support of the avocado industry. All expressions of opinion are not to be regarded as expressing the opinion of Horticulture Australia Ltd or any authority of the Australian Government. The Company and the Australian Government accept no responsibility for any of the opinions or the accuracy of the information contained in this report and readers should rely upon their own enquiries in making decisions concerning their own interests.

ISBN 0 7341 2609 3 Published and distributed by: Horticulture Australia Ltd Level 7 179 Elizabeth Street Sydney NSW 2000 Telephone: (02) 8295 2300 Fax: (02) 8295 2399 © Copyright 2011

Potential implications of climate change and climate policies for the Australian avocado industry AV09003 Jane Muller David Putland Peter Deuter Simon Newett

December 2010 Growcom 68 Anderson St Fortitude Valley PO Box 202 Fortitude Valley QLD 4006 Tel: 07 3620 3844 | Fax: 07 3620 3880 www.growcom.com.au

Potential implications of climate change and climate policies for the Australian avocado industry. Final report for HAL project #AV09003. 24 December 2010 Jane Muller & David Putland Growcom 68 Anderson St Fortitude Valley QLD 4006 [email protected] [email protected] Peter Deuter & Simon Newett Agri-Science Queensland [email protected] [email protected]

Climate change and the Australian avocado industry

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Contents Executive summary ................................................................................................... 5 Acknowledgements ................................................................................................... 6 1.0 Introduction ........................................................................................................ 7 1.1 Background to the project............................................................................... 7 1.2 Overview of the report .................................................................................... 7 1.3 Background to avocado production in Australia .............................................. 8 1.4 Background to the avocado crop .................................................................... 9 2.0 Climate requirements for avocado production ................................................... 11 2.1 Temperature................................................................................................. 11 2.2 Rainfall ......................................................................................................... 17 2.3 Relative humidity .......................................................................................... 19 2.4 Atmospheric carbon dioxide ......................................................................... 19 2.5 Solar radiation .............................................................................................. 21 2.6 Key climate requirements for avocado production ........................................ 21 3.0 Projected climate changes for Australian avocado production regions ............. 23 3.1 The link between carbon emissions and climate change .............................. 23 3.2 Australian climate changes in the past 100 years ......................................... 24 3.3 Climate projections for Australian avocado production regions ..................... 25 3.4 Key findings.................................................................................................. 41 4.0 Critical climate issues and shifting opportunities for avocado regions and varieties................................................................................................................... 43 4.1 Key findings.................................................................................................. 46 5.0 Climate management and adaptation options for avocado producers............... 48 5.1 Literature review of management options to address key climate risks......... 48 5.2 Summary of management strategies to address climate change .................. 58 5.3 Key findings.................................................................................................. 66 6.0 The carbon emissions impact of avocado production ....................................... 67 6.1 The concept of carbon footprints .................................................................. 67 6.2 Methodology for calculating emissions from avocado production.................. 68 6.3 Results ......................................................................................................... 70 6.4 How carbon footprints can be used in the avocado industry ......................... 76 6.5 Further development of carbon footprinting tools .......................................... 77 6.6 Key findings.................................................................................................. 78 7.0 Carbon labeling ................................................................................................ 79 7.1 International trends....................................................................................... 79 7.2 Australian trends........................................................................................... 80 7.3 Assessing the potential costs and benefits of carbon labeling....................... 81 7.4 Key findings.................................................................................................. 81 8.0 Carbon markets and emissions trading ............................................................ 82 8.1 Options for addressing carbon emissions ..................................................... 82 8.2 The proposed Carbon Pollution Reduction Scheme ..................................... 84 8.3 Agricultural offsets and the carbon market.................................................... 90 8.4 The role of agriculture in emissions trading and carbon markets .................. 93 8.5 Developments in emissions policy following the 2010 federal election.......... 94 8.6 Key findings.................................................................................................. 97 9.0 Potential implications of carbon emissions trading and carbon markets for the Australian avocado industry .................................................................................... 99 9.1 Financial and business impacts .................................................................... 99 9.2 Impact of baseline data, emissions estimation methods and monitoring frameworks.........................................................................................................101 9.3 The relative competitiveness of agricultural and forestry industries .............102 9.4 Emerging business opportunities and requirements from carbon offsets .....102


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9.5 Key findings.................................................................................................104 10.0 Conclusions and critical industry issues.........................................................105 11.0 References....................................................................................................108


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Executive summary This project aims to determine the potential impacts of climate change on the avocado industry, identify specific management strategies that can be employed in different production regions, and summarise key matters arising from climate policies that are relevant to the avocado industry. A thorough review of the existing literature explored the effects of a number of climate variables on avocado production. The review identified significant variation in climatic requirements among the numerous varieties, and also highlighted the lack of research on the ‘Shepard’ variety which is widely grown in the hotter northern regions. Through this project, regional climate projections have been prepared and presented to illustrate the potential level of climate vulnerability across major avocado production regions. While these projections provide a handy estimate of potential climate risk, the results must be interpreted with a degree of caution considering the limitations of the available data and the availability of a range of adaptation strategies that may mitigate the risk. The projections show that the amount of climate change and level of associated risk is likely to vary considerably among the regions. For example, north Queensland and some areas in southeast Queensland are likely to face the greatest challenges. In contrast, some regions appear to be relatively secure, particularly coastal New South Wales and southwest Western Australia. In addition, some areas may become more favourable to avocado production, including coastal Tasmania and higher altitude inland areas in New South Wales. The climate projections do not suggest an imminent industry crisis. Over the next several decades, growers in some regions may encounter challenging conditions more frequently than at present, and these conditions may require adaptation measures to be employed. In the longer term (40-70 years), these challenges are likely to become more acute. A review of the literature regarding management strategies identified a number of options that growers can implement to help mitigate or manage these projected climate changes. Overall, these management options should increase the industry’s adaptive capacity and provide a level of resilience to climate change. Table 5 provides a detailed list of possible adaptation strategies and management responses that may be appropriate for particular climate threats. In brief, the list of options includes site selection, the selection of suitable varieties and rootstocks, orchard layout, canopy management, pest and disease management, mulching and irrigation. Four avocado growers participated in a carbon footprinting exercise for this project. These footprint results provide preliminary data that may be useful for communicating the industry’s relatively minor contribution to greenhouse emissions. The footprinting process provides growers with an initial step to explore potential marketing opportunities or possibilities in the emerging carbon markets. This report provides a detailed review of a range of climate policies that may impact on the avocado industry. Unfortunately, the dynamic state of policy development hinders any firm conclusions at this point. We anticipate that important policy details will become clear, if not finalised, by the end of 2011.


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The opportunities for agricultural industries to participate in the carbon market are unclear given that the eligibility of the many potential abatement activities is yet to be determined. The opportunities for avocado growers, in particular, appear to be very limited. Further details are required on the range of eligible abatement activities, the likely compliance costs of participation in the carbon market, and the expected carbon price. This report concludes with a series of recommendations for further work that should be supported by the avocado industry. These recommendations include: • Additional detailed modelling of critical climate thresholds at particular growth stages, including both temperature envelopes and changes to rainfall patterns. • Research on the ‘Shepard’ variety which may gain in prominence under altered climatic conditions. • The development of new varieties and rootstocks that are better suited to future climate conditions. • Collate information on management practices that could be applied to simultaneously achieve productivity, sustainability, adaptability and abatement.

Acknowledgements Growcom wishes to thank the avocado growers who volunteered for the trial of the carbon footprint calculator for their valuable contributions to this project. The project team appreciated the time the growers made available, the efforts made to prepare for our visit and gather together the data required for the calculator, the information and perspectives shared during our discussions, and their hospitality. Thanks also to Antony Allen, Executive Officer, Avocados Australia Ltd for his valuable advice and for providing industry information and statistics.


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1.0 Introduction 1.1 Background to the project Climate change is an issue of significant national and international concern. This project, Climate change and climate policy implications for the Australian avocado industry (AV09003), aims to: •

Identify projected future temperature and rainfall changes in Australia’s avocado growing regions.

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Investigate the impacts of projected climate changes on avocado production.

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Identify management strategies that may assist the avocado industry to adapt to climate variability and climate change.

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Identify any production regions that may be at risk from climate change, along with new areas that may become suitable for production.

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Assess greenhouse gas emissions from avocado orchards.

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Review implications and opportunities for the avocado industry arising from government climate change policies and market based initiatives, including emissions trading, carbon offsets and carbon labelling.

The project is funded by Horticulture Australia Limited (HAL) and Avocados Australia Limited (AAL) and is being delivered by Growcom and Agri-Science Queensland. Growcom is the peak body for the horticulture industry in Queensland, providing representation, leadership and smart solutions for horticulture businesses (www.growcom.com.au). Agri-Science Queensland is a unit within the Queensland Government Department of Employment, Economic Development and Innovation. Agri-Science Queensland invests in and conducts world-class science and assists with the application of science outcomes and innovations by agri-businesses (www.dpi.qld.gov.au/4791_17999.htm).

1.2 Overview of the report In section two of this report, the climatic requirements of avocado crops are outlined, based on a review of scientific literature. The review explored the effects of temperature, rainfall, atmospheric carbon dioxide levels, solar radiation and relative humidity on key phenological events, plant physiology, yields, fruit quality and the incidence of pests and diseases. Through the review, we have sought to identify any critical climatic requirements, optimal conditions and climate thresholds. In section three, brief background information regarding the link between greenhouse gas concentrations and climate change is provided, along with a summary of key changes that have been recorded in Australia’s climate over the last ten years.


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Climate projections for Australia’s avocado production regions are presented for the years 2020, 2050 and 2080, based on customized climate modelling and mapping. An assessment of the potential impacts on the avocado industry of the projected climate changes is presented in section four. Section five includes a review of the management strategies that may be available to avocado growers to manage climate variability and adapt to climate change. The strategies were identified through a review of scientific and management literature. In section six, the results of the application of a carbon footprint calculator on four case study farms are presented along with a brief discussion on the possible application of carbon footprint information within the industry. Section seven provides a brief overview of national and international trends in displaying carbon emissions information on product labels. Emissions trading schemes and carbon markets are described in section eight, including details on the Carbon Pollution Reduction Scheme (CPRS) that was proposed by the former Rudd Labor Government. This section also outlines the potential role of agricultural industries in emissions trading. Finally, it outlines progress in international arrangements to address climate change and in discussions regarding carbon pricing options in Australia. Section nine provides an analysis of implications and possible business impacts for avocado producers arising from the potential introduction of emissions trading, based on economic analyses of the proposed CPRS. The conclusions chapter, section ten, draws the various analyses together to assess the overall implications for the avocado industry and suggest useful areas for continuing investigation.

1.3 Background to avocado production in Australia The Australian avocado industry comprises 1100 growers across the country and produces 46,500 tonnes of avocados each year worth $AUD180 million at the farm gate and $430 million at retail level (Avocados Australia Ltd). Key growing areas are North, Central and Southeast Queensland, Northern and Central New South Wales, the Sunraysia or Tristate area (South Australia, Victoria and South Western New South Wales) and Western Australia. Around 5 488 hectares are under production. While avocados have been grown in Australia since the nineteenth century, the commercial industry was established as recently as the 1960s. The size of the industry has doubled in the last 10 years (Antony Allen, pers. comm.) and 34% of trees are under 6 years old (Allen 2009). Around 78% of national production is grown in Queensland, where the major production regions are Bundaberg-Childers, Atherton Tablelands, Toowoomba and the Sunshine Coast. New South Wales and Western Australia each produce around 10% of the national production (Antony Allen, pers. comm.). A diversity of varieties is grown, generally grouped as ‘Hass’ or greenskins. Around 79% of national production is ‘Hass’, around 15% is ‘Shepard’ (grown predominantly


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in the warmer regions of Queensland) and the remainder is a mix including ‘Sharwil’, ‘Wurtz’, ‘Reed’, ‘Bacon’ and ‘Fuerte’.

Figure 1. Avocado varieties by proportion of production (source: Avocados Australia website).

Fifty-two percent of avocados are purchased through supermarkets with another 29% purchased through independent grocers. Climate change has been identified as a critical industry issue along with food security, modernization of the horticultural award wages system, the global financial and economic crisis and biosecurity (Allen 2009).

1.4 Background to the avocado crop Avocados have been commercialized relatively recently. While a significant body of research is developing for the crop, the scientific literatures is somewhat limited compared to more established crops such as apples. This has made assessment of the climatic factors critical to successful avocado production more of a challenge, and it should be noted that there is virtually no peer-reviewed scientific literature regarding one of Australia’s key varieties, ‘Shepard’. The avocado, Persea americana Miller, is a tropical and sub-tropical evergreen tree producing a large oily fruit. The varieties of avocado that are grown commercially around the world are from three distinct ecological races or botanical varieties: • P. americana var. drymifolia (Mexican), • P. americana var. americana (West Indian) and • P. americana var. guatemalensis (Guatemalan). The Mexican and Guatemalan ecotypes originated in subtropical/tropical highland environments and the West Indian ecotypes originated in tropical lowland Climate change and the Australian avocado industry

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environments. Each geographical ecotype has distinctive adaptations and horticultural and botanical features (Perez-Jimenez 2008) which influences their adaptability to environmental conditions. Avocados are grown commercially in many countries around the world, in three distinct climatic zones: • Cool, semi-arid with winter dominant rainfall, e.g. California, Israel, Chile. • Humid, sub-tropical with summer dominant rainfall, e.g. Australia , Mexico, South Africa. • Tropical / semi-tropical with summer rainfall, e.g. Brazil, Florida, Indonesia. Successful avocado production requires a warm climate and protection from frost. After grafting, avocado trees begin to crop after three years, peaking around eight to nine years of age. A production span, however, can last up to 20 years. Depending on the production region, avocado fruit takes between six and 15 months to grow to maturity. For a short period in cooler regions, trees carry last season’s mature fruit and next season’s recently set immature fruit. Avocado fruit does not ripen until it is mature and removed from the tree. Avocado has a unique flowering behaviour known as complementary, synchronous, dichogamy (Schaffer and Whiley 2002). Group A varieties, such as ‘Hass’, ‘Pinkerton’, ‘Reed’, ‘Rincon’ and ‘Wurtz’, open as female in the morning of the first day and male in the afternoon of the second day. Group B varieties, such as ‘Fuerte’, ‘Bacon’, ‘Edranol’, ‘Ettinger’ and ‘Kona Sharwil’, open as female in the afternoon of the first day and male in the morning of the second day.


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2.0 Climate requirements for avocado production Avocados are known to be highly sensitive to both climatic and edaphic factors (Wolstenholme 2002). Climatic conditions affect avocado physiology, phenology, productivity and yields, fruit quality and the incidence of pests and diseases. To explore these effects and to identify optimal and threshold conditions, the scientific literature has been reviewed to identify the influence of temperature, rainfall, relative humidity, atmospheric carbon dioxide (CO2) levels and solar radiation. Regarding pests and diseases, the most serious threat to avocado production is the soil-borne fungal disease Phytophthora root rot (known in Mexico as “la tristeza del aguacate” or “sadness of the avocado”) which is caused by Phytophthora cinnamomi Rands. Other problems common in avocados include anthracnose, stem end rots, and fruit damage caused by fruit borers, fruit spotting bugs and thrips. There are a broad range of other pest and disease issues that can affect avocado, including other fungal root rots, cankers, verticillium wilt, cercospora (or black) spot, scab, sooty blotch, bacterial blast, bacterial soft rot, and sun blotch. Most pest and disease problems are influenced by temperature, rainfall and humidity.

2.1 Temperature The preferred average annual temperature range for group A varieties is 6.5°C to 19°C and for group B varieties is 10°C to 20°C (Praloran in Whiley et al. 2002). A number of authors suggest that average daily temperatures between 20°C to 25°C provide optimal conditions for general growth, root growth, flowering and fruit set for most varieties (Lahav and Trochoulias 1982; Sedgley and Annells 1981). Lahav and Trochoulias (1982) found a day/night temperature range of 25/18°C resulted in optimal root growth and dry matter accumulation in ‘Fuerte’, while the range was 21/14°C for ‘Hass’. Optimum photosynthetic rate for the variety ‘Edranol’ has been found to occur at a temperature range of 19-24°C (Bower et al. in Bower and Cutting 1988), although this is not a commercial variety in Australia. Maximum net photosynthetic rates for ‘Fuerte’ occurred between 28-31°C (Scholefield et al. in Schaffer and Whiley 2003). Temperature has a major influence on the avocado’s reproductive biology and is the key factor triggering the change from vegetative growth to the reproductive stage (Gazit and Degani 2002). During anthesis, temperature can severely disrupt the dichogamy, though Group A trees are generally more tolerant of both cooler and warmer temperatures (Schaffer and Whiley 2002). For example, Lahav and Trochoulias (1982) found that ‘Hass’ was less adversely effected by temperature extremes. Flowering, pollination and fruit set have been found to be the most critically temperature sensitive stages for avocado. While avocado flowering and pollination can be affected by low temperatures, high temperatures are more detrimental. High temperatures accompanied by low relative humidity are particularly damaging (Wolstenholme 2002). Research suggests that each avocado variety probably has its own specific temperature optima and thresholds.


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A six to eight week period of cool weather is required for the initiation, development and growth of inflorescences. During the flower development phase (from bud break to the point of flowering), night temperature of 5-10˚C stop vegetative and shoot growth and promote good flowering. Night temperature should not exceed 15˚C. Day temperature should not exceed 25˚C, though 20˚C preferred. (Vock et al. 2001) Buttrose and Alexander (1978a) report that effective temperatures for flower initiation in ‘Fuerte’ were 20°C during the day and between 5 and 10°C at night. For ‘Hass’, 23/18°C day/night is likely to be the critical point for flowering (Gazit and Degani 2002). Loupassaki and Vasilakakis (1995) found that optimum in vitro germination of ‘Fuerte’ pollen occurred at 25°C. These authors also reported results suggesting the optimum temperature for avocado pollen germination was between 25°C and 29°C. Gazit and Degani (2002) note that while the typical flowering season extends for approximately 2 months, it will be shorter in warmer weather and longer in cooler weather.

2.1.1 Effect of low temperatures Flowering can be adversely affected by low night temperatures. Overnight temperatures around 10-12°C appear to be a threshold below which problems with pollination and fruit set start to emerge for many varieties (Lomas 1988; Zamet 1990); low temperatures have been found to reduce the number of flowers that open with a female stage (particularly in group B varieties), delay or retard the pollination process and slow pollen tube growth (Argaman 1983; Gafni 1984; Sedgley and Annells 1981; Sedgley and Grant 1982/1983). Group B varieties are less productive under cool conditions than group A. Low temperatures also reduce the activity of pollinating insects (Bergh 1967; Peterson 1955). A temperature regime of 17/10°C day/night was found to restrict root growth and dry matter accumulation in both ‘Hass’ and ‘Fuerte’ (Lahav and Trochoulias 1982). A number of studies investigating the effect of temperature on avocado yields have also confirmed 10°C as a threshold for yield decline (Bower and Cutting 1988; Lobell et al. 2007; Zamet 1990). Some studies, however, have shown that minimum temperatures may be less important than the diurnal temperature range, which influences the period of time both male and female flowers are open concurrently (Sedgley and Grant 1982/1983). Gafni (1984) found that low night temperatures of 5°C for 3-4 nights did not decrease fruit set in ‘Ettinger’ and ‘Fuerte’, and even cold minimums which commenced immediately after pollination and continued through the fertilisation process caused no damage. He concluded that regular low night minimums during most of the fruitset season are not a limiting factor of avocado fertility. Others have suggested that low temperatures may be more detrimental when they are sustained over a prolonged period such as a week or more (Argaman 1983; Zamet 1990). Other experiments suggest that the absence of high temperature is more important than low temperatures (Buttrose and Alexander 1978b).

2.1.2 Effect of high temperatures While there is some variation in the evidence presented in the literature regarding low temperature thresholds, there is strong agreement regarding the negative effects of


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high temperature – both high day or maximum temperatures and high night minimum temperatures. Researchers report that high day or maximum temperatures have a negative effect on root growth (Lahav and Trochoulias 1982), shorten the flowering period (Sedgley et al. 1985); cause abnormalities in flowers (Sedgley et al. 1985), cause pollination or fruit set failure or pollen tube burst (Argaman 1983; Gafni 1984; Sedgley and Annells 1981), and fruit abscission (Sedgley et al. 1985). Upper temperature thresholds appear to be 33°C for flowering and 35-37°C during fruit set. Photosynthesis has also been found to be irreversibly damaged by 35-37°C temperatures (Schaffer and Whiley 2003). These high temperature thresholds are also reflected in research on yields (Bower and Cutting 1988; Buttrose and Alexander 1978b; Lobell et al. 2007; Zamet 1990). Growers who participated in the carbon footprinting component of this project also confirmed these temperature thresholds from their experience. Lahav and Trochoulias (1982) found the 30-37°C range reduced root growth and dry matter accumulation by 60-70% compared with optimal temperature ranges for ‘Hass’ and ‘Fuerte’. At 33°C, fruit abscission occurred in ‘Hass’ and ‘Fuerte’ varieties (Sedgley and Annells 1981) and daytime maximums of 35°C during flowering and fruit set caused all fruit to drop 10 days after pollination (Sedgley and Annells in Lomas 1988). ‘Hass’ could withstand short periods of temperatures above 30°C (Sedgley and Annells 1981). Gafni (1984) found that a day/night range of 32/22°C for three weeks from the day of pollination caused significant decline in fruit set of ‘Fuerte’ and that for all varieties 24 days exposure to 20-22°C minimums and 38-39°C maximums damaged pollination and fruit set. Mature pollen was affected by several hours exposure to 34°C. Argaman (1983) also found that a temperature regime of 32-35°C day and 21-23°C night temperature lasting one week caused damage to ovules and especially to the pollen of ‘Fuerte’. Pollen tubes rarely penetrated the ovary or reached the embryo sac. On the other hand, pollen from the ‘Ettinger’ variety was unaffected by temperatures almost as high. Sedgley et al. (1985) note that during flowering, a high night temperature and a high average diurnal temperature may be more significant than the daily maximum temperature. Studies of Californian crop yields also showed that night minimum temperatures in excess of 12°C during flowering and fruit set were detrimental to avocado yields (Lobell et al. 2007). High temperatures during fruit maturation, however, may assist post harvest fruit quality, as exposure to high temperatures on the tree can improve tolerance to low temperatures during storage (Ferguson et al. 1999). High temperatures impact on the rate of photosynthesis: 32.2°C has been identified as the threshold for closure of the stomata in avocados (Liu in Hofshi 1998). A two year trial on the impact of harvesting avocados in high temperatures (McCarthy 2009) tested the effect of high temperatures on softness, skin colour, body rots, vascular browning, diffuse discolouration and stem end rots. High temperatures at harvest (over 30°C) and delays in placing fruit into cool storage did impact on these quality parameters, but most impacts were minor. Body rot was found to be the most


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significant impact; the incidence increased by 0.17 with each 1˚C increase in temperature (based on a two hour delay in cooling). Woolf and Ferguson (2000) discuss the effects of high flesh temperatures in fruit in the field on post harvest quality. High flesh temperatures (up to 15°C above the air temperature) can be recorded in the exposed side of fruits. In avocado, this can prolong ripening time by around 1.5 days but may improve fruit quality. ‘Hass’ and Fuerte fruits exposed to direct sunlight were found to be firmer than shaded fruits because sun exposure affected cell wall enzyme activity (Woolfe et al. 1999 in Moretti et al. 2009). McCarthy (2009) also found, in Western Australia, that the pulp of fruit exposed to direct sunlight was consistently 5-8˚C higher than the ambient air temperature. ‘Hass’ fruits have been found to be 17% smaller when grown in warm coastal environments compared to cool highland environments (Schaffer and Whiley 2002), so higher temperatures during fruit development may negatively affect fruit size. Research by Heath and Arpaia (2007) confirmed the effect of high temperatures on lowering carbon accumulation which led to smaller fruit and lower overall yields in California. Research by Cutting (1993) suggests that the tendency of the ‘Hass’ variety to produce smaller fruits in warmer environments may be related to concentrations of zeatin and dihydrozeatin type cytokinins in the seed and testa which were greater in fruit from cooler areas than warmer areas. While the relationship between cytokinin concentrations and testa health is still to be determined, it does appear to influence cell division throughout the life of the avocado fruit. Moretti et al. (2009) review research showing how the postharvest quality of fresh fruit and vegetable crops can be directly and indirectly affected by high temperatures and exposure to elevated levels of carbon dioxide. The review notes that temperature increase can affect photosynthesis (through modulation of enzyme activity and electron transport chains), altering sugars, organic acids, flavanoids, firmness and antioxidant activity. Above certain temperature thresholds, many enzymes lose their function, potentially changing plant tissue tolerance to heat stresses. Dry matter content (a harvest indicator used for avocado) directly correlates with oil content. ‘Hass’ avocados grown under higher temperatures (45˚C compared to 30˚C) had a higher moisture content and a reduced oil composition (Woolfe et al 1999 in Moretti et al. 2009).

2.1.3 The impact of temperature on avocado pests and diseases Outbreaks of pests and diseases can occur when changes in climate result in more favourable conditions for their growth, survival and dissemination (reviewed in Aurambout et al. 2006). Phytophthora root rot is undoubtedly the most destructive and important disease of avocado, limiting production in almost every country it is grown (Pegg et al. 2002; Perez-Jimenez 2008). Phytophthora is caused by the oomycete Phytophthora cinnamomi Rands, which destroys the fine feeder roots of avocado, limiting uptake of water and nutrients, in time killing the tree (Pegg et al. 2002). Its survival is strongly determined by clear temperature ranges, though soil moisture levels are also critical. Root rot is more severe and develops more rapidly in soils with poor drainage;


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disease development is optimal in wet soil at temperatures ranging between 21 to 30°C (Pegg et al. 2002). Zentmyer (1981) found in a Californian avocado orchard, maximum infections occurred during summer and autumn where maximum soil temperatures at 10cm depth were 24.5-25.5°C. Little or no infection occurs at or above 33°C or below 13°C (Pegg et al. 2002; Zentmyer 1981). Zentmyer (1981) also notes that the preferred temperature ranges for P. cinnamomi and its avocado host were very similar. Under natural conditions, there are great seasonal variations in P. cinnamomi populations in soils which are correlated with soil temperature and, when temperatures are conducive, with soil-water potential (Perez-Jimenez 2008). Infections occur in the temperature range 15-27°C, though the optimum temperatures are between 22-26°C (Zentmyer 1981). Even when soil temperatures are optimal, however, the pathogen cannot survive outside the host if soil water potential is low (Zentmyer 1980 in Perez-Jimenez 2008), although some propagules such as chlamydospores can survive for many years under these conditions. Research on Australian isolates of P. cinnamomi has found that growth did not occur outside a temperature range of 5-35°C (Shepherd and Pratt 1974). Phillips and Weste (1985) also found for Australian isolates that in vitro growth occurred at temperatures between 10-30°C, with a maximum growth rate at 25-30°C. In international research, Zentmyer et al. (1976) tested 187 P. cinnamomi isolates from 24 countries and 59 hosts. They reported that the optimum temperature range for growth was 21-30°C, with most cultures growing best between 24-27°C. Their results confirmed findings from other authors of in vitro cardinal temperature ranges for growth of P. cinnamomi : minimums between 5-16°C; optimum growth between 20-32°C; and maximum temperatures 30-36°C. Perez-Jiminez (2008) reports no growth at temperatures above 33-34°C and populations are limited when soil temperatures are less than 10°C. She also notes that P. cinnamomi does not survive 2-3 days at 36°C; 1-2 hours at 39°C and 1030minutes at 45°C. Nesbitt et al. (1979) investigated the effect of temperature and soil moisture on the formation of hyphal lysis and sporangi in P. cinnamomi. Hyphal lysis formed most rapidly in soils incubated at 25-27°C. Sporangia were not formed at temperatures below 15°C. Studies of the effectiveness of soil disinfestation using solarisation provide another perspective on temperature thresholds for P. cinnamomi. Soil infested with P. cinnamomi was covered with clear plastic to raise the soil temperature: the research showed that P. cinnamomi was inactivated after 1-2 hours at soil temperatures of 38°C, and that 1-2 hours of 40°C was required to kill all propagules when chlamydospores were present (Gallo et al. 2007). Other studies have investigated the effect of microbial antagonists of P. cinnamomi in organic mulches applied to avocado orchards (You and Sivasithamparam 1995). This research showed that the fungal and bacterial microbes in mulch decreased the infectivity of P. cinnamomi and that increasing temperatures and moisture content in the mulch had a significantly positive influence on their populations. The authors suggested that phytophthora root rot could possibly be limited by monitoring and manipulating the temperature and moisture of organic mulches.


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Denner et al. (1986) studied fungi that cause anthracnose and stem end rot: Colletotrichum gloeosporioides and Dothiorella achieved germination between the temperature range of 10-35°C, but optimal germination occurred at 25-30°C. For initiation of germination, temperatures needed to be between 20-35°C for at least 3 hours. No germination or growth occurred at 5°C or 40°C. Appressoria were produced at temperatures between 10 and 30°C. The optimal temperature for growth was 28°C, while temperatures exceeding 30°C and less than 10°C retarded growth. Denner et al. (1986) concluded that anthracnose infection will not take place at temperatures of 10°C or lower and temperatures lower than 15°C or exceeding 28°C will prevent extensive infection. He notes that further research would be required to assess the effects of soil moisture. A major insect pest in avocado are coreid fruit spotting bugs, Amblypelta nitida and A. lutescens lutescens, which can cause severe damage to fruit, particularly in orchards close to the natural habitat of the insects such as rainforest, wet sclerophyll forests, dry Acacia/Eucalyptus forests and riparian vegetation (Drew 2007; Waite and Martinez-Barrera 2002). Fruit spotting bugs are common in Queensland and New South Wales but are not recognized as a problem in Western Australia or Sunraysia. Surveys of growers have identified that most fruit spotting bug damage occurs between November and February. Bugs have been found to be less active and move shorter distances in cool conditions. In temperatures in excess of 32°C bugs become highly active and fly longer distances, leading to sharp increases in damage in orchards. Growers have noted that damage to orchards is most common in southeast Queensland when there are hot northerly or north-westerly winds and high temperatures, particularly in orchards where there is a rich alternate habitat to the north of the orchard (Drew 2007). Studies show that the avocado fruit borer (Stenoma catenifer) insect pest has a low temperature development threshold of 8°C, and the viability of these insects was greatest in the 18-28°C range (Nava et al. 2005). Temperature can also influence the success of beneficial insects that assist in the biological control of winged insect pests such as fruit borers. Studies of Trichogramma species note a minimum temperature threshold of around 11°C (Maceda et al. 2003). More specific research showed T. pretiosum required a minimum temperature greater than 10.7°C and 151.83 degree days growing in the eggs of the host Mediterranean Flour Moth Anagasta kuehniella (Lepidoptera: Pyralidae) while T. acacioi required a minimum temperature greater than 10.46°C and 155.46 degree days in the same host (Pratissoli et al. 2005). Maceda et al. (2003) tested the effects of 15, 20, 25 and 30°C temperatures: maximum parisitisation of host Anagasta kuehniella (Lepidoptera: Pyralidae) occurred at 25°C; developmental rates for Trichogramma were similar at 20, 25 and 30°C and very slow at 15°C. Ploetz (2009) encourages avocado producers to remain vigilant to the potential of new diseases and problems which may emerge as climate changes drive broader shifts in the behaviours and ranges of pathogens and host species. Laurel Wilt (a disease of tree species in the Laurel family (Lauraceae), caused by a fungus (Raffaelea lauricola) that is introduced into host trees by the Redbay Ambrosia Beetle (Xyleborus glabratus) is suggested as an example of an emerging global threat to avocado production due to climate change.


pg 16

2.2 Rainfall 2.2.1 Effect of rainfall on phenology, yield and quality Wolstenholme (2002) provides a summary of the optimal rainfall conditions for avocado. In subtropical growing areas with summer dominant rainfall, 1000mm per annum is considered the minimum required. Irrigation is necessary in many production regions, for example in the winter dominant rainfall regions, such as Western Australia and during the dry spring in summer dominant rainfall areas. Avocado water needs vary across the phenological growth stages: low water requirements during winter, moderate to high during flowering, high during the midsummer fruit drop period and second aerial growth flush phase, and moderate during the general growing period (Whiley in Wolstenholme 2002). Changes in rainfall could have negative effects on avocado production regions. The key risks are both around reduced rainfall impacting on the availability of irrigation water and the impacts of increased rainfall intensity. Significant reductions in rainfall in production regions could cause water deficit stress or inadequate irrigation supplies. Water stress can occur suddenly, even at relatively low soil water tension, due to the avocado’s shallow root system, causing wilting or abscission of leaves or fruits (Bower and Cutting 1987; Bower et al. 1977). If fruit is not shed, size and quality may be affected (Bower and Cutting 1988). Maintaining optimal water status after fruit set is critical to sustain fruit growth; any setback in fruit growth has been found to be irreversible (Cutting 1984). Vock et al. (2001) note that: • Severe water stress can occur during flowering, because the evaporative surface of the tree increases by up to 90% and flowers are unable to control water loss as they have no stomates. This can have significant impact on yield. • Water stress during early fruit growth can affect fruit size, quality and overall yield. • Water stress during summer can cause ring neck, particularly during hot dry conditions. Experiments with partial and whole root zone drying irrigation treatments also showed that reduced water supply caused fruit abscission due to the dry soil around the roots rather than the water status of leaves or fruit (Neuhaus et al. 2009). Water deficit stress has been found to significantly influence fruit ripening physiology. Avocados are unusual in that they only ripen after fruit have been removed from the tree. The chemical triggers for the ripening process are not well understood, however, long term water stress, particularly in the first three months of fruit development, has an irreversible effect on the ethylene evolution pattern, ripening rates, ripening evenness and fruit quality (Bower and Cutting 1988). Water stress also increased the activity of browning enzymes in ripe fruit after storage (Bower 1988). Increased incidence of intense rainfall events could also pose significant management risks for orchards. Too much rain during flowering can cause flower shedding and reduce crop set (Wolstenholme 2002). Bower and Cutting (1987) Climate change and the Australian avocado industry

pg 17

report that excess water can reduce yield and fruit quality by reducing root oxygen availability and also creating conditions for root rot infection to occur. Low oxygen supply to the roots impacts on the uptake of essential nutrients (Labanauskas et al. 1978). High rainfall at critical stages has also been found to affect fruit set or cause fruit drop (Baxter in Bower and Cutting 1987). If soils are waterlogged for more than 2 days due to excessive rain or surface flooding, there is a high probability of tree death (Schaffer and Whiley 2002). Harvesting can be disrupted by rain and dew. It is recommended that ‘Hass’ fruit should not be picked if it is wet as there is some evidence fruit harvested when wet has an increased incidence of lenticel damage and vascular browning (Duvenhage 1993).

2.2.2 The effect of rainfall on avocado pests and diseases As the growth rates and survivability of many of the key avocado pests and diseases increase under conditions of high soil moisture content, changes in annual total precipitation or seasonal and short term rainfall patterns could have significant implications for avocado production. Phytophthora root rot develops best where there is an excess of water in the soil. The moisture assists pathogen development and is a factor in the formation, dispersal and germination of spores (Perez-Jimenez 2008). Zentmyer (1980) notes that the disease can progress in well-drained soils under frequent rainy conditions or in especially rainy years. Wolstenholme (2002) notes that if rainfall exceeds 1800mm/yr and there are several consecutive months of greater than 300mm per month, the risk of soil water logging and, therefore, root rot is severe. Low soil water suction pressure is the key issue, rather than absolute water content. Sporangia production will be higher in a sandy soil than a clay soil with equal water contents, because clay has a higher water suction pressure (Perez-Jimenez 2008). Rapid drying and rewetting of unmulched soils has also been found to cause large swings in soil salinity which makes the roots more susceptible to P. cinnamomi infection (Downer et al. 2002). High rainfall and high relative humidity can also encourage diseases such as cercospora spot, anthracnose and scab, and insect pests such as thrips and scales (Wolstenholme 2002). For example, high humidity (>80%) and temperatures between 18 and 26°C promote anthracnose infections (Whiley et al. 2002; Wolstenholme 2002). Anthracnose, caused by the fungus Glomerella cingulata (Colletotichum gloeosporioides) can occur in all production regions, especially in wet years but it is most common in eastern Australia where there is high summer rainfall. In south-west Western Australia the critical periods are autumn and spring. The ‘Fuerte’, ‘Rincon’ and ‘Wurtz’ varieties are the most susceptible, while ‘Hass’, ‘Pinkerton’, ‘Sharwil’ are the most tolerant due to higher levels of dienes (antifungal compounds) in the skin (Vock et al. 2001). There are two forms of anthracnose infection. The first follows insect damage and continues to develop causing rotting of the fruit. The second occurs in conditions where free surface water is present on fruit for 48 hours (for example, after rain, dew or irrigation). In this case, spores that land on the fruit surface germinate and


pg 18

penetrate the skin with an infection peg (or appressorium), which remains dormant until the fruit begins to ripen and its dienes (anti-fungal compounds) begin to break down, allowing the infection to develop (Vock et al. 2001). Conidia of C. gloeosporioides can be produced in large numbers on dead leaves and twigs entangled in the canopy of the avocado orchard, which can be washed through the tree in rainy weather. For this reason, Anthracnose infection usually occurs during prolonged warm showery weather (Wolstenholme 2002). Scab is noted as a problem in the humid tropics and subtropics where cool wet conditions are favourable for infection (Ploetz 2009).

2.3 Relative humidity In general, a high relative humidity is beneficial for avocado production as it alleviates physiological stress and supports moderate to high stomatal conductivity and photosynthesis (Wolstenholme 2002). High humidity during and after fruit set is particularly important (Bower and Cutting 1988). The effect of high temperatures is exacerbated if it is accompanied by hot dry winds and low relative humidity (Wolstenholme 2002). Bower et al. (1977) showed that decreasing relative humidity caused a decline in stomatal conductance and decreased photosynthetic responses. Relative humidity in excess of 32% has been reported as optimal during flowering and fruit set (Human in Bower and Cutting 1988). Avocado pollen viability is improved by higher relative humidity (Loupassaki and Vasilakakis 1995). Bower and Cutting (1988) also report that any sharp decreases in relative humidity after fruit set can cause fruit drop. Wolstenholme (2002) also notes that temperatures above 40°C accompanied by wind and very low relative humidity (less than 20%) cause significant abscission of newly set fruit. Humid conditions associated with high rainfall, however, can encourage pest and disease problems including cercospora spot, anthracnose, scab, thrips and scale (Wolstenholme 2002) .

2.4 Atmospheric carbon dioxide The potential effects of increased atmospheric carbon dioxide (CO2) concentration on agricultural productivity have now been the subject of a considerable volume of work (reviewed in Drake et al. 1997; Jablonski et al. 2002). The main effect of increased atmospheric CO2 on plants is increased resource use efficiency (Drake et al. 1997). Exposure to elevated CO2 concentration may lead to increased growth and productivity if the increase in CO2 concentration also leads to elevated temperatures (Ro et al. 2001). For example, water use efficiency often increases as a result of reduced stomatal conductance and transpiration, while lightuse efficiency also increases as a result of increased photosynthetic rates. There are potential negatives to increased atmospheric CO2. For example, there are some indications that weed species may respond to higher CO2 more readily than


pg 19

domesticated crops (eg. Ziska and Bunce 1993), while the greater carbon to nitrogen ratio may lead to reduced nutrient content. Jablonski et al. (2002) conducted an analysis of plant responses to elevated CO2 across 79 species (both crop and wild). This analysis revealed a general pattern of more flowers, more fruits (an average of 28% in crops) and more seeds at higher CO2 concentrations, but lower seed nitrogen concentrations. Another meta-analysis of “free air CO2 enrichment” (FACE) experiments by Ainsworth & Long (2005) revealed a similar suite of effects, but with a lower stimulation of crop yield of 17%. The results of these more recent experiments showing lower than expected responses to increased CO2 cast doubt on earlier projections that rising CO2 will fully offset losses due to climate change (Long et al. 2006). In addition, many of the earlier chamber experiments use enriched conditions of twice the current ambient CO2 concentration which may enhance productivity gains. Current political responses to climate change have a general goal of stabilizing atmospheric concentrations at approx. 450ppm (about 1.2 times current ambient conditions). Responses to enriched CO2 are crop-specific. For example, long-term experiments on citrus have revealed significant increases in growth and yield (Kimball et al. 2007) under conditions of elevated CO2, while the results have been equivocal for other crops. Possible sources of this variation among crops include different cropping systems, physiologies, research methodologies, water availability and nutrient availability (Cure and Acock 1986). Interactions between increased CO2 and higher temperatures further complicate the issue. There appears to be very little research directly addressing the effect of CO2 enrichment on avocado growth and productivity. Under elevated CO2 (600 µmol mol-1), fruit loss occurs more rapidly for the first 25 days after anthesis but then the rate of loss levels off (Whiley 1999). In contrast, although the rate of fruit loss from trees grown at 350 µmol mol-1 CO2 is lower during the first few weeks after anthesis, fruit drop continues to occur for a longer period. As a result, trees grown at 600 µmol mol-1retained more fruit at 40 days after anthesis than did those grown at 350 µmol mol-1. The higher rate of fruit loss during the first 25 days for trees grown at elevated CO2 may be a result of increased partitioning of photoassimilates into vegetative growth during the period of early fruit development. For example, trees grown under elevated CO2 display a greater allocation of dry matter to new leaves, new branches, trunk and roots. While Whiley’s study demonstrated that increased atmospheric CO2 results in increased avocado fruit retention, he was unable to demonstrate an increase in yield under elevated CO2. Furthermore, this work assumes that mean temperatures in tropical and subtropical areas will not increase by more than 1-2˚C (which now seems unlikely; section 3.3), and that water and nutrients are not limiting. Enrichment of atmospheric CO2 increased the accumulation of biomass in several tropical fruit trees, including avocado (reviewed in Schaffer et al. 1999). In avocado, an increase in fruit yield may be indirect and delayed, resulting from increased water and nutrient uptake via increased root mass (Schaffer et al. 1999). In vitro experiments using micro-propagated avocado plants show no change in maximum net photosynthetic rate between ambient and enriched (approx. 2.6 x ambient) CO2 conditions with constant sucrose concentration in the growth medium (de la Vina et al. 1999). However, the ratio of leaf to stem and root fresh weight was greater in plants grown under the enriched conditions. When radiation was not limiting, net


pg 20

photosynthetic rate was greater under enriched conditions (de la Vina et al. 1999). Better shoot growth and higher rates of biomass accumulation under enriched CO2 conditions have also been observed by Witjaksono et al. (1999). This lack of information on avocado responses to enhanced atmospheric CO2 forces us to rely on the general observations of responses across multiple crop species to infer likely impacts on avocado production. Based on this information, the projected increase in atmospheric CO2 is likely to have a positive but relatively small influence on fruit yields. However, in those regions that are expected to experience fairly high temperature increases, the effect of CO2 enrichment is unlikely to counteract the negative impact of higher temperatures.

2.5 Solar radiation There is little information on the critical amount of light required for productive avocado orchards (Wolstenholme 2002). Avocados appear to grow well in areas that receive at least 2000 hours of sunshine annually (Gaillard and Godefroy 1995, cited in Wolstenholme 2002). Production areas in California and Israel receive between 3000 and 3500 hours of sunshine per year, mostly during the summer. Incident light has a major effect on the rate of photosynthesis. For avocados, maximum photosynthetic rate is achieved at an incident light level about 1/3 to 1/2 that of full sunlight (reviewed in Schaffer and Whiley 2002), reflecting the understorey rainforest origin of the species. Direct sunlight can elevate the surface temperature of exposed fruit between 5 and 11°C above ambient temperature (Schroeder and Kay 1961), increasing the risk of fruit damage from elevated temperatures. In fact, some studies have shown surface temperatures as high as 18°C above ambient air temperature (Woolf et al. 1999). The amount of the temperature increase depends on the incident light level, degree of exposure, fruit colour and air temperature. There is little precise information on the likely changes to cloud cover and therefore sunlight hours that may accompany future climate change. It is likely that the southern half of Australia will receive a slight increase in sunlight hours while the north will have little change. Fortunately, the relatively low light requirement of avocados enables a range of management practices that can minimise the impacts of high air temperatures on fruit quality and yield.

2.6 Key climate requirements for avocado production This review suggests that key climate requirements and thresholds for avocado production include: • •

In general, optimal conditions for avocado production are an average daily temperature of between 20-25°C. A frost free climate is preferred, though mature trees can tolerate -4˚ for short periods without damage.


pg 21

• •

•

•

• • •

• •

•

•

•

Trees can tolerate temperatures of 40˚C for short periods. Prolonged exposure to high temperatures causes severe stress and loss of productivity Following the summer growth stage, a 6 to 8 week period of cool weather is required for floral initiation and growth of inflorescences (generally between May and July). During the flower development phase (from bud break to the point of flowering), night temperatures of 5-10˚C stop vegetative/shoot growth and promote good flowering. Night temperature should not exceed 15˚C. Day temperature should not exceed 25˚C, though 20˚C is preferred. During flowering and fruit set, the preferred day/night temperature range for ‘Fuerte’ is 25/18°C and for ‘Hass’ is 21/14°C. Night minimum temperatures of 10°C or lower may be a threshold for negative effects on flowering and pollination for some varieties. A maximum daytime temperature threshold of 33°C or above during flowering and fruit set causes pollination failure and abscission of fruit. High night time minimums can also damage flowering, pollination and fruit set. During the early fruit development period (August to November in eastern production regions), 35-37˚C is the maximum temperature threshold. Relative humidity should generally exceed 32%, particularly during flowering and fruit set. In subtropical growing areas with summer-dominant rainfall, successful avocado production requires at least 1000mm of rainfall per year. In most production regions, adequate water supplies are necessary to provide irrigation during the dry season and or at times of high water demand. Water requirements are highest during flowering and the mid-summer fruit drop period. Water stress and low relative humidity are particularly damaging to fruit development and post harvest fruit quality if they occur during the first three months of fruit development. Heavy or prolonged rain during flowering and fruit set is detrimental to crop set, and intense rain over a number of consecutive days at any time of the year can waterlog soils, increasing the risk of root rot and anthracnose infections. The preferred temperature ranges for key avocado pests and diseases are very similar to that of the avocado. Phytophthora cinnamomi root rot disease development is optimal in wet soils where soil temperatures are 21-30°C. Little or no infection occurs at or above 33°C, or below 13°C. Optimal conditions for anthracnose infection occur within a temperature range of 18-26°C and relative humidity in excess of 80%.


pg 22

3.0 Projected climate changes for Australian avocado production regions 3.1 The link between carbon emissions and climate change The Earth’s climate is regulated, in part, by a finely balanced mix of greenhouse (or “heat trapping”) gases in the atmosphere. There is now strong agreement amongst the majority of international climate scientists that human activities are causing dramatic increases in the volume of greenhouse gases in the atmosphere and this is driving changes in global climates. Significant changes in temperatures and shifts in rainfall patterns have already been observed across the world over the last century and climatic modelling projects an accelerating rate of change into the future. Climate modelling suggests that, over the coming decades, Australia is likely to experience: • Higher average temperatures with more hot days and fewer cold nights • Heavier rainfalls in a shorter wet season • Greater unpredictability and more extreme weather events Climate change is regarded as a critical issue of international significance. There are ongoing efforts to reach international agreement on how to reduce the emissions of greenhouse gases. The Intergovernmental Panel for Climate Change (IPCC) believe that atmospheric greenhouse gas concentrations should be stabilised at 450 parts per million (currently approx. 380 ppm) to slow the rate of climate change and limit average temperature increases to approximately 2˚C. This would require cuts to worldwide emissions of between 50 and 85% by 2050 relative to 2000 (IPCC 2007). There are many greenhouse gases in the Earth’s atmosphere. The international community have agreed that there are six key gases of concern: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydro-flourocarbons (HFCs), perflourocarbons (PFCs) and sulphur hexafluoride (SF6). These gases vary in the degree to which they trap heat in the atmosphere, depending on their radiative properties and life span in the atmosphere – this is known as their global warming potential (GWP). Each gas is weighted according to its effect relative to that of carbon dioxide (CO2) using an internationally accepted scale. This allows all greenhouse gases to be expressed in “tonnes of carbon dioxide equivalents” (or tCO2e) and collectively referred to as “carbon emissions” or “greenhouse gas emissions” (see Table 1). Table 1. The Global Warming Potential (GWP) of the six main greenhouse gases. Gas Formula GWP Carbon dioxide CO2 1 Methane CH4 21 Nitrous oxide* N2O 310 Hydrofluorocarbons HFCs 1,300 Perfluorocarbons PFCs 7390 – 17,700 Sulphur hexafluoride* SF6 22,800


pg 23

International agreements use emissions in the year 1990 as a baseline against which increases or decreases of carbon emissions can be measured and targets set. Human activities that release significant amounts of greenhouse gases include: • power generation (eg. coal or gas-fired power stations) • transport (eg. burning of fuels in motor vehicles) • manufacturing • agriculture Agricultural industries contribute approximately 16% of Australia’s total emissions. The main greenhouses gases emitted from agriculture are nitrous oxide (primarily from nitrogenous fertilisers), carbon dioxide (from burning fuels and crop residues) and methane (from livestock or waterlogged soils). The horticulture industry contributes a very small share of carbon emissions from the agriculture sector. Horticulture generates approximately 1% of the emissions from all of agriculture, which translates to only about 0.2% of total national emissions.

Figure 2. Australia’s greenhouse emissions profile illustrating the relative contributions from each of the major sectors. Agricultural industries have the second largest contribution to national emissions (about 16%) behind stationary energy generation. Modified from the National Greenhouse Gas Inventory 2006, Department of Climate Change.

3.2 Australian climate changes in the past 100 years Howden et al. (2006) provide a useful review of climate changes that have been experienced over the previous 100 years in eight key avocado producing regions in Australia. These changes can be very generally summarized as:


pg 24

• • • • • • •

An increase in mean annual temperature, particularly due to an increase in night minimums and warmer winter-spring temperatures. A decrease in diurnal temperature range. An increase in heat stress days and solar radiation. Declining frost risk, with the date of the last frost becoming earlier. Increasing relative humidity. Some minor decline in mean annual rainfall, though the decline was only statistically significant in the Bundaberg region. An increase in estimated evaporation rates.

Howden et al. (2006) also outline projected climate changes in these regions for 2030, 2050 and 2070. Their findings included that the projected changes were consistent with the trends which have occurred for the previous 100 years.

3.3 Climate projections for Australian avocado production regions National scale climate projections (reported in Webb and Whetton 2010) indicate that: • Lower rainfall along with increased temperatures and evaporation will cause reduced inflows to catchments and less availability of water supply for irrigation while water demands of crops will increase. • The risk of large hail events will double for the NSW coast to 4-6 days / year. • Drier soils and reduced cloud cover may increase frost risks in spite of increasing mean temperatures (as the daily temperature variation has a major influence on frost risk). • The frost risk may stay the same or increase for perennial crops that experience earlier bud burst. • Drought intensity and duration is likely to increase. • The incidence of severe storms is likely to increase. • The overall number of cyclones per season is likely to decrease; however, the proportion of intense cyclones is projected to increase. • The frequency of extreme rain events is expected to increase. For this report, national projections have been refined using the latest available data and modelling. Three methods are presented to assess the potential impacts of projected temperature increases on avocado production: • climate projection maps for avocado production regions, • critical threshold modelling, and • bioclimatic modelling.

3.3.1 Climate projection maps The following maps provide an easy visual representation of the projected temperature changes for several key avocado regions. As with all analyses based on projected climate data, the results must be interpreted with caution because of the levels of uncertainty and margins for error in the underlying models. However, these results can provide a valuable indication of the level of climate risk that may face each growing region.


pg 25

Projections of rainfall changes have not been mapped as meaningful or accurate analysis of likely rainfall changes is extremely difficult to achieve from current climate modelling. Each page provides data for a single climate variable that may be expected to affect avocado production (eg. maximum summer temperature, maximum spring temperature or minimum winter temperature). Within each page, separate maps illustrate the projected temperatures across the four regions and over four points in time: current, 2020, 2050 and 2080. Data on current climate conditions was extracted from the WorldClim dataset (http://www.worldclim.org/). Data on future climate conditions data was extracted from CSIRO climate models featuring a medium emissions scenario (a2a model). Both datasets provide a spatial resolution of 2.5 arc-minutes (resulting in approximately 5km grid squares). Each colour represents a 5˚C temperature band. Blue dots indicate the locations of avocado farms from the membership database of Avocados Australia. The mapping was performed using DIVA-GIS (version 7.1, http://www.diva-gis.org/). Figure 3 illustrates the projected changes in maximum summer temperatures. Under the scenario presented here, most of the avocado production areas will see little increase in the current temperatures to 2020 (within the same 5˚C band). However, many sites in Queensland and northern NSW may experience temperature increases of 5 to 10˚C by 2080. In contrast, the summer temperature regime in southwest Western Australia appears to be relatively stable to 2080. Figure 4 displays the projected changes in maximum spring temperatures (September) which may be an important determinant of fruit set. For the production areas in Queensland and NSW, this scenario suggests that most orchards may experience an average temperature increase of about 5˚C by 2080. Temperature changes to 2020 appear to be relatively small and variable by location. In Western Australia, the southern area around Manjimup appears to be relatively stable while the area around Perth may experience slightly higher temperature increases. Projected changes in winter minimum temperatures are illustrated in figure 5. The small increases in minimum winter temperatures suggested across most regions may be beneficial for productivity but may not compensate for the negative impacts of higher temperatures in other seasons. Table 2 provides a generalized summary of the projected climate changes for the avocado regions. In summary, for most avocado production regions, substantial temperature changes are unlikely in the current 20 year orchard planning horizon.


pg 26

2020

2050

2080

SW WA

N NSW

SE Queensland

N Queensland

current

200 km

Temperature (˚C).

Figure 3. Projected changes in mean maximum summer temperatures (January) for major avocado production regions. Climate change and the Australian avocado industry

pg 27

2020

2050

2080

SW WA

N NSW

SE Queensland

N Queensland

current

Temperature (˚C)

200 km

Figure 4. Projected changes in mean maximum spring temperatures (September) for major avocado production regions.


pg 28

2020

2050

2080

SW WA

N NSW

SE Queensland

N Queensland

current

Temperature (˚C)

200 km

Figure 5. Projected changes in mean minimum winter temperatures (July) for major avocado production regions. Climate change and the Australian avocado industry

pg 29

Table 2. Regional summary of projected changes in summer maximum, spring maximum and winter minimum temperatures (°C) North Queensland / Atherton Tablelands Current 10-15 Winter mean min Spring mean max Summer mean max

(some areas 5-10) 20-25 (some areas 25-30) 25-30

2020

2050

2080

10-15

10-15

10-15

25-30

25-30

25-30

25-30

30-35 (some areas 25-30)

30-35

Bundaberg/Childers Winter mean min Spring mean max Summer mean max

Current

2020

2050

2080

5-10 (some areas 10-15) 25-30

10-15 (some areas 5-10) 25-30

10-15

10-15

25-30

25-30 (some areas 30-35)

30-35

30-35

25-30 (some areas 30-35) 35-40

Sunshine Coast Current

2020

2050

2080

Winter mean min

5-10

5-10

10-15

Spring mean max

20-25

Summer mean max

25-30

25-30 (some areas 20-25) 25-30

10-15 (some areas 5-10) 25-30 30-35

30-35 (some areas 35-40)


pg 30

25-30

West Moreton Current

2020

2050

2080

Winter mean min

5-10

5-10

10-15

Spring mean max

20-25

Summer mean max

30-35

25-30 (some areas 20-25) 30-35

5-10 (some areas 10-15) 25-30 30-35

25-30 (some areas 30-35) 35-40

North Coast NSW Current

2020

2050

2080

Winter mean min

5-10

5-10

10-15

Spring mean max

20-25

20-25

Summer mean max

25-30

25-30 (some areas 30-35)

5-10 (coastal strip 10-15) 25-30 (some areas 20-25) 30-35 (some areas 25-30)

30-35 (some areas 35-40)

Current

2020

2050

2080

5-10 20-25 25-30

5-10 20-25 25-30 (some areas 30-35)

5-10 25-30 30-35

5-10 25-30 30-35

25-30

Central Coast NSW Winter mean min Spring mean max Summer mean max

South West WA and Perth district Current 5-10 Winter mean min 15-20 Spring mean max Summer mean max

25-30 (SW) 25-35 (Perth)


2020

2050

2080

5-10 15-20 (SW) 20-25 (Perth) 25-30 (SW) 30-35 (Perth)

Coastal strip 10-15 15-20 (SW) 20-25 (Perth) 25-30 (SW) 30-35 (Perth)

10-15 15-20 (S SW) 20-25 (Perth and N SW) 25-30 (SW) 30-35 (Perth)

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3.3.2 Critical threshold modelling The literature review has identified a number of critical temperature thresholds that represent potential limits to successful avocado production. A number of these temperature characteristics can be modelled and mapped to illustrate changes in suitable areas under various climate scenarios, although the potential for this approach is limited by the available climate data. These critical temperature thresholds that are suitable for this approach and for which relevant data is available include: • • •

July minimum temperatures below 15˚C (for flower induction) but above 4˚C (to avoid cold damage). September minimum temperature above 12˚C for effective pollination. Temperatures below 33˚C during flowering and fruiting (October or November depending on the region) to avoid the negative impact of high temperatures on fruit set.

The data for current September minimum temperatures above 12˚C shows a poor fit with the current distribution of Avocado orchards, suggesting either that this factor may not be a good predictor of orchard location or that current practices (local site selection, managed pollination etc.) are quite successful in managing negative impacts. In comparison, combining a July minimum temperature between 4˚C and 15˚C with a November maximum temperature below 33˚C provides a critical temperature envelope that includes most of the current avocado production regions. These temperature thresholds can then be used to explore the impacts of projected climate changes. Figure 6 presents a series of maps that illustrate the projected changes in this critical temperature envelope across the four regions and over four points in time: current, 2020, 2050 and 2080. Similar to the previous section, the data on current climate conditions was extracted from the WorldClim dataset (http://www.worldclim.org/). Future climate conditions data was extracted from CSIRO climate models featuring a medium emissions scenario (a2a model). Both datasets provide a spatial resolution of 2.5 arc-minutes (resulting in approximately 5km grid squares). The dark green colour identifies those areas where all of these temperature conditions are met. Blue dots indicate the locations of avocado farms from the membership database of Avocados Australia. The mapping was performed using Quantum GIS (version 1.6, http://www.qgis.org/). The results of this mapping suggest that the impacts of projected climate change will vary across the regions. For example, increasing temperatures may present challenges to some north Queensland producers by 2050, particularly in coastal areas. In contrast, there may be no change in southwest Western Australia. In southeast Queensland, there may be little change in most areas until 2080. Increased winter minimum temperatures in NSW may lead to an expansion of suitable areas. Climatic conditions in many parts of Tasmania may also become more suitable for avocado production as a result of warmer winter temperatures (figure 7).


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2020

2050

2080

SW WA

N NSW

SE Queensland

N Queensland

current

Figure 6. Projected changes in the critical temperature envelope for major avocado production regions. Dark green indicates those areas that meet all criteria (July min. temp. between 4˚C and 15˚C and November max. temp. below 33˚C).


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current

2050

2020

2080

Figure 7. Projected changes in the critical temperature envelope across Australia. Dark green indicates those areas that meet all criteria (July min. temp. between 4˚C and 15˚C and November max. temp. below 33˚C).

While these maps provide a useful guide to the level of potential climate risk facing these regions, the results should be viewed with a degree of caution. There is a degree of uncertainty in the spatial data and underlying climate models. Other important factors in addition to climate may have important effects, and the process ignores climate adaptation measures that may already be in place or that may be applied in the future. For example, the climate parameters chosen for these maps were derived from literature based on the ‘Hass’ variety, while ‘Shepard’ is the major variety in the north Queensland region.


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3.3.3 Bioclimatic modelling Bioclimatic modelling (a type of environmental niche modelling) is a method of analysing and visualising how the spatial distribution of a species may be influenced by climatic conditions. It is widely used in ecological research but can also be applied to agricultural commodities. This technique uses data on geographic locations (such as species observation records) and numerous layers of climate data to construct a bioclimatic envelope that describes the suite of climatic conditions that are suitable for the given species or crop. Once the bioclimatic envelope has been identified, it is possible to model how the area of suitable conditions may change or move in response to future climate change. The following figures (8-12) are based on simple bioclimatic modelling using only three climate variables – maximum temperature in the warmest month, minimum temperature in the coldest month and annual precipitation. The selection of relevant climate variables to include in the modelling process is critical. Unfortunately, the currently available data do not include some climate variables that may be more relevant for agricultural crops, such as frost days, heat stress days, or temperature data on a sufficiently fine temporal scale to identify minimum or maximum temperatures at particular phenological stages. Similarly, the accuracy of modelling is dependent on the accuracy of the location data. In this analysis, the spatial data represents the locations of members of Avocados Australia (postcodes converted to geographic coordinates) rather then the exact locations of avocado orchards. Importantly, this analysis only considers climatic variables and ignores other key factors that can influence the viability of avocado orchards. It also does not consider adaptation strategies that may enable production to continue at the current locations in the face of future challenging climatic conditions. While these results should not be used to inform industry planning decisions, they do illustrate the potential value of this approach. The modelling can be refined once specific temperature thresholds are identified and more relevant data is available. The modelling was performed using DIVA-GIS (http://www.diva-gis.org/). Current data is based on WorldClim climate data (http://www.worldclim.org/) and future data is based on the CCM3 model (the Community Climate Model from the National Center for Climate Research) using twice current atmospheric CO2 concentration (Govindasamy et al. 2003). Both datasets feature spatial resolution of 2.5 arcminutes (approx. 5km grid squares).


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Figure 8. Avocado orchard locations based on data provided by Avocados Australia (postcodes of members converted to geographic coordinates).


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Figure 9: The results of a simple bioclimatic model of avocado orchard distribution based on current climatic conditions using only 3 climate variables – maximum temperature in the warmest month, minimum temperature in the coldest month and annual precipitation. Suitable areas are shown in green.


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Figure 10. These results illustrate the shift in suitable area based on predicted climate data under a scenario of double current atmospheric CO2 concentration. The results suggest that the growing regions of Sunraysia and the lower Murray may be at risk. The core growing areas along the east coast and southwest corner appear secure.


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Figure 11. This illustrates the potential contraction of areas suitable for avocados following an average temperature rise of 2˚C. Similarly to the case illustrated in figure 10, the major changes are seen in the Sunraysia region and lower Murray. Some regions along the Queensland coast may experience challenging conditions, while some areas in northern Tasmania may become more suitable.


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Figure 12. The potential contraction of areas suitable for avocados following an average temperature rise of 4˚C. Under this scenario, much of the productive areas along the Queensland coast, the Murray and northern section of southwest WA may be at risk. This scenario also suggests an expansion of potentially suitable areas in Tasmania.


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3.4 Key findings There are some consistent patterns in the level of projected climate risk across the different mapping methods and data used. The climate projections for the avocado regions generally show that: • •

•

•

Climate changes are likely to vary considerably among avocado growing regions. Most east coast and southern production regions are likely to experience significantly less than a 5°C increase in summer maximum temperatures by 2020, but may face a 5-10°C increase by 2080. Changes to maximum spring temperatures by 2020 may be small and variable across locations. There may be an average increase of up to 5°C by 2080. Increases in winter minimum temperatures may be small.

Projections indicate temperatures rises over time in most production regions, in some cases within 10 years. Warming in most regions, however, is not expected until 2050 to 2080. For the following summary, the extent of warming is less than 5°C, unless otherwise indicated. •

North Queensland may experience some warming of spring temperatures by 2020. Summer temperatures are projected to rise by 2080; some areas by 2050. Winter temperatures are projected to experience little change.

•

In the Bundaberg/Childers region, winter temperatures may rise by 2050, in some locations by 2020. In spring, some areas may experiences temperature increases by 2080. Key changes are in summer temperatures which may increase by 2020 and increase further by 2080 – a temperature rise of between 5°C and 10°C.

•

For the Sunshine Coast, winter temperatures are not projected to increase until 2080, though some areas may be affected by 2050. Spring temperatures may increase by 2050, with some parts affected by 2020. Summer temperatures are projected to increase by 2050 and may be higher still by 2080.

•

In West Moreton, winter temperatures are not projected to increase until 2080, though some areas may be affected by 2050. Spring temperatures may increase by 2050, with some areas affected by 2020. Summer temperatures are not projected to increase until 2080.

•

For Northern NSW, winter and spring temperatures are not projected to increase until 2080, though some coastal areas may warm by 2050. Summer temperatures may increase by 2050, with some areas affected by 2020.

•

For Central NSW, no changes are projected for winter temperatures. Spring and summer temperatures may increase by 2050. Some areas may experience an increase in summer temperatures by 2020.

•

For the Perth district, winter temperatures may warm by 2080. Spring and summer temperatures are projected to increase by 2020.


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•

In south-west Western Australia, while winter temperatures may warm by 2080, spring and summer temperatures are not projected to change within the period up until 2080.

Using the climate threshold modelling method, production sites in coastal North Queensland may lose climate suitability by 2020. Some inland parts of the Sunshine Coast and the Toowoomba range district of West Moreton may lose climate suitability by 2080. The areas with a suitable climate for avocado production may expand in NSW. South-west Western Australia and Sunraysia appear to retain their suitable climates for the remainder of the projection period and an expanding area of Tasmania may experience a suitable climate. Using the bioclimatic modelling method, under a scenario of double the current concentrations of atmospheric CO2, Sunraysia and the Atherton Tablelands may no longer experience a suitable climate for avocado production. Under a scenario of warming by 2°C Sunraysia, the Atherton Tablelands and the North Queensland production areas may experience challenging climatic conditions, while areas of Tasmania may become more suitable, climatically, for production. Under a scenario of warming by 4°C, most of Queensland’s production areas, Sunraysia and Perth appear to no longer have a suitable climate. The climate of New South Wales may remain suitable and an increased area of Tasmania may become more suitable for avocado production.


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4.0 Critical climate issues and shifting opportunities for avocado regions and varieties The review of the scientific literature (section 2) identified a set of key climatic requirements for successful avocado production. These include: • • • •

•

•

• •

• •

•

In general, optimal conditions for avocado production are an average daily temperature of between 20-25°C. A frost free climate is preferred, though mature trees can tolerate -4˚ for short periods without damage. Trees can tolerate temperatures of 40˚C for short periods. Prolonged exposure to high temperatures causes severe stress and loss of productivity Following the summer growth stage, a 6-8 week period of cool weather is required for floral initiation and growth of inflorescences (generally between May and July). During the flower development phase (from bud break to the point of flowering), night temperature of 5-10˚C stop vegetative/shoot growth and promote good flowering. Night temperature should not exceed 15˚C. Day temperature should not exceed 25˚C, though 20˚C is preferred. During flowering and fruit set, the preferred day/night temperature range for ‘Fuerte’ is 25/18°C and for ‘Hass’ is 21/14°C. Night minimum temperatures of 10°C or lower may be a threshold for negative effects on flowering and pollination for some varieties. A maximum daytime temperature threshold of 33°C or above during flowering and fruit set causes pollination failure and abscission of fruit. During the early fruit development period (August to November in eastern production regions), 35-37˚C is the maximum temperature threshold. In subtropical growing areas with summer-dominant rainfall, successful avocado production requires at least 1000mm of rainfall per year. In most production regions, adequate water supplies are necessary to provide irrigation during the dry season and periods of high water demand. Water requirements are highest during flowering and the mid-summer fruit drop period. Water stress and low relative humidity is particularly damaging to fruit development and post harvest fruit quality if it occurs during the first three months of fruit development. Heavy or prolonged rain during flowering and fruit set is detrimental to crop set, and intense rain over a number of consecutive days at any time of the year can waterlog soils, increasing the risk of root rot and anthracnose infections.

The climate projections for the avocado regions show that: • •

•

•

Climate changes are likely to vary considerably among avocado growing regions. Most east coast and southern production regions are likely to experience significantly less than a 5°C increase in summer maximum temperatures by 2020, but may face a 5-10°C increase by 2080. Changes to maximum spring temperatures by 2020 may be small and variable across locations. There may be an average increase of approximately 5°C by 2080. Increases in winter minimum temperatures may be small.


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One parameter that is critical to avocado production and most sensitive to climate change is the maximum temperature during the flowering and fruit set season. Table 3 outlines the timing of key phenological events across each production region for the main varieties grown. The flowering and fruit set season, from north to south through Australia’s production regions, extends from late winter through to very early summer. To assess the implications for the avocado industry of the projected climate changes, projected spring maximum temperatures in each region (figures 3-7) have been assessed to determine if successful fruit set may be jeopardized by future climate change. The assessment is based on the identified optimum temperature during flowering of 21°C for ‘Hass’ and upper temperature threshold of 33°C, above which there is an increased risk of pollination failure and abscission of fruit. These optima and thresholds were confirmed both in the literature and by growers who participated in the project (section 6). This assessment indicates that: • •

• • •

The Atherton Tablelands and North Queensland region may be at risk of experiencing some high temperature extremes during spring by 2020. The Bundaberg/Childers region may already be at the upper margin of a comfortable spring climate envelope, however, increases in average spring maximum temperatures may not affect the region until 2080. The Sunshine Coast and south-east Queensland may be at risk of experiencing some high spring temperature extremes during spring by 2020. The north and central coasts of New South Wales may be at risk of experiencing some high temperature extremes during spring by 2050. Western Australian production regions may not be affected by increases in average spring temperatures for the projection period.

It is interesting to compare this assessment with the simple bioclimatic modelling presented in Figures 8-12 that shows that with an average annual temperature rise of 2°C, farms in north Queensland and the Bundaberg/Childers area may face climatic challenges. In contrast, the same rise in average temperature may see some more temperate regions (such as northern Tasmania) become more suitable for avocado production. Under a more extreme scenario of a 4°C increase in average temperature, the climates of Queensland, Sunraysia and the Perth district may become unsuitable for avocado production without adaptation. Overall, the mapping and modelling presented in this report suggests that the most significant climate risk appears to be in North Queensland, where challenging climatic conditions may lead to a contraction in the suitable growing area by 2050. In contrast, the effects of climate change appear to be patchy for Bundaberg-Childers, the Sunshine Coast, West Moreton and New South Wales. South-west Western Australia appears to be at low risk of impacts from climate change. The climate threshold and bioclimatic modelling suggest there may be opportunities for industry expansion into suitable areas of Tasmania by 2050. In general, the projections do not suggest a climate crisis for the avocado industry. In most cases, the projected temperatures rises outlined in figures 3 to 5 are within the climate thresholds for key phenological events. Given the planning horizon of 10 to 20 years in the avocado industry, it appears likely that growers would have sufficient time to monitor climate changes and respond in advance.


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Table 3 Timing of key phenological events in production regions (source: Simon Newett in consultation with other extension officers and key reference growers in each production region) Production region & variety

Flowering season

Fruit development (size up / fill out)

Harvest season

Late August to end September Mid-July to midSeptember

September to March

Late March to end May

August to January

Mid January to end March

September to mid-October Mid-August to early October

October to April

Mid April to mid-August

September to February

Early March to end April

Mid-September to mid-October

October to April

Coastal areas: End April to September Maleny / Bellthorpe range: Early August to December

Mid-September to early November

October to June

Toowoomba Range: Early July to end December Gatton area: Early June to end December

September to mid-October

October to June

July to November inclusive

September to mid-November

October to May October to August

Coastal areas: June to October inclusive Comboyne Plateau: September to February

October to midNovember

November to September

October to December inclusive

October to early November

November to August

Early September to midDecember

October to early December

November to November

December to February inclusive

Atherton tablelands •

Hass

•

Shepard

Bundaberg/Childers •

Hass

•

Shepard

Sunshine Coast •

Hass

West Moreton •

Hass

Northern NSW •

Hass

Mid North Coast NSW •

Hass

Lower Murray / Tristate •

Hass

Perth district •

Hass

SW Western Australia •

Hass


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While in most cases, projected winter temperatures seem to present little risk for flowering failure, there does appear to be a higher risk of spring temperature increases having the potential to damage pollination, fruit set or early fruit development. Increased summer temperatures are likely to present a lower risk if growers are able to implement the management strategies outlined in section 5. There are, however, broader considerations that should be taken into account. A simple assessment of the temperature projections can overlook the potential for increased risks of unseasonable spikes in temperature which, if these occur over a number of days during a critical period such as fruit set or early fruit development, could cause significant crop impacts. Further, the literature review has indicated critical climate parameters that have not been able to be addressed in the current project. Detailed climate modelling around these parameters could reveal more immediate or significant threats to avocado production. It is recommended that the full suite of critical climate requirements be further investigated at regional scales by a specialist climate modelling team, possibly focusing on regions identified in this report as most at risk. Critical areas for further investigation include: • •

• •

• •

•

Will existing production regions continue to experience a 6 to 8 week window in May to July of 5-10°C nights and 20°C days to establish good flower set? What is the risk of spring temperatures increasing or spiking erratically causing damage to the flowering process, fruit set or early fruit development? In particular, what is the risk of the production regions experiencing spring temperatures above 33°C degrees. What are the trends for night minimum temperatures and diurnal temperature ranges during flowering seasons? What is the risk of frost occurring in regions that previously were largely frost free or with greater frequency in areas that were previously light frost risk areas. How will rainfall patterns change and what is the risk of intense rainfall events occurring during the flowering period or harvest season? What is the risk of intense rainfall events that deliver more rain than soils can drain away? What is the likelihood of intense rain events extending for more than 48 hours (for example, associated with cyclones)? What is the risk of increased incidence of drought conditions?

4.1 Key findings This review of the critical climate issues for avocado production combined with the projected climate changes does not suggest that the Australia avocado industry is facing a climate crisis. The production areas most at risk within the next 10-20 years, as a result of the potential for excessively high temperatures during the fruit set and early fruit development stages, appear to be the Atherton Tablelands in north Queensland and some areas in southeast Queensland. Over this period, growers in these regions may encounter challenging conditions more frequently than at present. The review has also highlighted that detailed modelling of critical climate parameters might provide clearer insights into specific climate threats to avocado production.


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However, this discussion of potential climate impacts has not yet addressed management practices and strategies that may be employed by growers to mitigate potential climate risks. The following chapter reviews a range of management options that should the industry’s adaptive capacity and provide a level of resilience to climate change.


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5.0 Climate management and adaptation options for avocado producers The scientific and management literature has been reviewed to identify the range of possible management practices that could be employed to respond to projected climate changes. Factors noted by the former Queensland Department of Primary Industries as critical to successful avocado production (Figure 11) have provided a useful structure under which to explore possible climate change adaptation strategies and management responses identified in the literature review. The potential adaptation and management strategies have then been summarized in a table outlining the projected climate changes, the potential impacts and the possible responses.

Figure 13. Avocado business success factors. (Source: Agrilink Avocado Information Kit; Vock et al. 2001)

5.1 Literature review of management options to address key climate risks The review is presented under the headings of the key areas of management for avocado businesses identified by Vock et al. (2001). Where relevant literature was not found for an area of management, the area has been omitted. In some cases


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management ideas canvassed with or suggested by avocado growers have been included.

5.1.1 Selection of sites with adequate soil drainage In order to minimize the risk of soil water logging or experiencing wet soil conditions that allow fungal diseases to thrive, guidelines for depths of freely draining soils are recommended when considering locations for the establishment of orchards (Vock et al. 2001): • • •

Where average annual rainfall is less than 700mm/year, soils should have free drainage to a depth of 1m. Where average annual rainfall is between 700-1500mm/year, soils should have free drainage to a depth of 1.5m. Where rainfall exceeds 1500mm/year, soils should have free drainage to a depth of 2m.

General climate projections for Australia suggest that while average annual rainfall totals may fall, rainfall intensity may increase, so the industry could consider revising soil drainage recommendations to account for extreme, though infrequent, rain events. Currently, there does not appear to be literature addressing this issue, so further research may be useful. Mounding has been identified as an appropriate practice if the depth of well-drained soil is only marginally less than required (Vock et al. 2001). Given the potential for increased incidence of intense rain events, mounding may become increasingly important.

5.1.2 Selection of sites with an appropriate climate When considering locations for the establishment of orchards, a suite of key climate parameters are recommended (Vock et al. 2001): • •

•

Frost free areas. During the flower development period (from bud break to the point of flowering) night temperatures should range between 5˚C to 10˚C and not exceed 15˚C; day temperatures should average around 20˚C and not exceed 25˚C. During the flowering period, night temperatures should not fall below 10˚C, particularly for temperature sensitive varieties such as ‘Shepard’ and ‘Sharwil’.

The use by orchard managers of an information and record management system is recommended (Vock et al. 2001) and the value of such systems in monitoring climatic conditions at the orchard site will become greater over coming years to identify temperature trends during critical phenological stages. Should monitoring indicate an increase in climate risk at the current site, it may be necessary to consider options for spreading climate risks, such as: • •

relocating the business, establishing orchards in multiple locations or


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•

transitioning, if necessary, into alternate crops better suited to the climate trend or projections for the existing site.

5.1.3 Business planning and financial management It is recommended that avocado enterprises prepare a five to ten year business plan and review it annually to ensure it reflects current business objectives. A financial management system should also be in place to ensure the financial position of the business is known at all times (Vock et al. 2001). The business planning and financial management processes can be used to plan options for and build financial capacity to implement strategies for spreading climate risks. Wolstenholme (2001) discusses international trends in the separation of land ownership and land operation with large operating companies (such as Dole or Chiquita) contracting growers in optimal sites and supplying technologies, processing arrangements, brands and marketing in order to extend seasons, regulate supplies, manage risks and control or shift cost-price issues. In light of these trends, it may be worthwhile for the avocado industry to consider the business structures that may be best equipped to optimize production, profits and adaptability in the context of climate variability and change.

5.1.4 Marketing It is recommended that avocado production is planned around a sound understanding of avocado markets (Vock et al. 2001). Individual businesses also collectively contribute to industry-wide marketing campaigns. Monitoring of international shifts in production and changes to importing and exporting patterns and how these are influenced by climate change could become a more important component of assessing opportunities in domestic and international avocado markets. A grower who was involved in the carbon emissions footprint case studies suggested that the industry consider preparing marketing strategies aimed at building consumer acceptance of or demand for smaller (or “lunchbox” sized) fruit in the event that an increasing proportion of small fruit is produced due to increasing temperatures in major ‘Hass’ production regions. Wolstenholme (2001) notes that future business success in avocado production may require an increased emphasis on partnerships and strategic alliances. Marketing cooperatives and other partnership approaches may be an effective strategy to increase a business’s adaptability to climate change.

5.1.5 Quality management To address the tendency of the ‘Hass’ variety to produce smaller fruits in warmer environments, Cutting (1993) suggests that exogenous application of cytokinins may assist fruit size in warmer areas. Cutting (1993) also recommends further research into management systems that prolong testa life and influence cytokinin content to naturally enhance fruit size, as the relationship between cytokinin concentrations and testa health is unclear.


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The timing of seed coat senescence may also be a factor in reduced fruit size (Wolstenholme et al. 1998) and could be managed through mulching (see section 5.1.9). A two year trial on the impact of harvesting avocados in high temperatures (McCarthy 2009) found that harvest temperature was not the most important factor influencing post harvest quality, but that a range of management practices should be observed to protect quality when harvesting fruit in temperatures in excess of 30˚C: • • •

Protect picked fruit from sun and wind as newly exposed fruit is highly susceptible to sunburn on hot dry days. Remove field heat from harvested fruit within 24hours. Store fruit at the appropriate temperature for the time it is to be stored.

5.1.6 Use of record keeping and information management systems It is recommended that growers maintain good records and use information management systems (Vock et al. 2001). Software such as AVOMAN provides an avocado orchard management tool, extensive record keeping facilities, information management functions, report generation tools, and customised agronomic advice. The value of operating advanced information management systems will increase in a context of increasing climate variability and climate change as the reports and analysis the system provides may assist growers to identify trends in climate and patterns of responses in the orchard. This level of monitoring and analysis could underpin adaptive management, particularly climate adaptation.

5.1.7 Varieties and rootstocks Rootstock selection may assist in managing elevated atmospheric CO2. Whiley (1999) noted that dwarfing or semi-dwarfing rootstocks are more likely to take advantage of enriched CO2, while rootstocks with increased nutrient uptake or translocation ability may be valuable if elevated CO2 is found to cause nutrient deficiencies. As ‘Shepard’ is better adapted to warmer conditions, and is well accepted by consumers, plantings of this variety may expand into more southern production regions as warming occurs. Given this potential expansion, there is a strong need for research focussed on the specific climatic requirements of ‘Shepard’ to address the paucity of information available for this variety. There is strong scope to identify or develop other alternate varieties better suited to the possible future climate conditions in established production regions. On-going research into rootstocks and varieties seems increasingly important to develop greater industry adaptability and resilience to expected changes in climate. Newett (1999) comments that clonal rootstocks may become more important in the Australian industry in future to achieve improved orchard productivity, quality and uniformity.


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5.1.8 Orchard layout, canopy management and top working Newett (1999) notes that tree thinning, staghorning, limb removal, hedgerowing with mechanical saws (usually to a pyramidal shape) and hedgerowing using plant growth regulators (PGRs) are commonly used to achieve canopy management. Major pruning is done following harvest but before hot weather commences to avoid sunburn. Newett (1999) also notes that the plant growth regulator (PGR) paclobutrazol is used on ‘Hass’ as a strategically timed foliar spray to increase fruit yield or fruit size. As avocado branches are highly susceptible to sunburn, any limbs exposed to the sun after pruning should be protected with whitewash, white plastic paint, or 5:1 mix of talc and bentonite in water (Vock et al. 2001). Work by Heath et al. (2005) investigated tree physiology and responses to environmental stress of ‘Hass’ in order to improve canopy management strategies in California – these could apply to Australian regions with Mediterranean climates and possibly more broadly. The project examined the response of avocado leaves to changes in light and temperature through carbon assimilation and evaporative demand. The research found that temperatures over 85˚F (29.4˚C) inhibit carbon assimilation, increasing CO2 in the leaf tissue, causing the stomata to close. The stomata closes slowly while transpiration continues so there is a high level of water loss and no carbon assimilation which lowers the productivity of the tree and increases the incidence of small fruit. While much research effort has focused on canopy management to optimize light and micro-climate in the orchard and to protect fruit and soils from direct sun exposure, the focus of canopy management is more to maximise productivity and quality. As such it is likely to be a minor consideration in responding to climate change.

5.1.9 Pest and disease management, particularly Phytophthora root rot and anthracnose As P. cinnamomi is now present in most soils, management actions must be taken to minimize the risk of infection and development of root rot. Seven areas of management that assist in guarding against infection have been identified: soil drainage, orchard quarantine, disease free nursery trees, appropriate selection of root stocks, mulching or cover cropping, irrigation and nutrition management and chemical control (Vock et al. 2001). Management practices are noted in these relevant sections. Other management practices noted by Ploetz (2009) include use of solarisation methods to disinfest soils prior to planting, use of raised beds and composts and application of biological as well as chemical controls. Ploetz (2009) also notes that multiple practices used in combination are most effective. Research on rootstocks suggests that for subtropical areas Velvick rootstocks provide some benefit in managing both Phytophthora and anthracnose by reducing the tree’s susceptibility to infection, reducing the severity of infection and making the tree more responsive to fungicide treatments (Vock et al. 2001). Duke 6 and Duke 7 rootstocks increase susceptibility of ‘Hass’ to anthracnose in wetter coastal regions. In contrast, in a ten year trial of ten clonally propagated rootstocks in California, Duke 7 consistently out-performed the other rootstocks in terms of cumulative yield and


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canopy efficiency. It is also the industry standard rootstock for its phytophthora and salinity resistant qualities (Mickelbart et al. 2007). It may, therefore, be an appropriate selection for Australian production regions with similar Mediterranean climates and soils. It is also recommended that the orchard is oriented so that interrows freely drain excess water in heavy rain events (Vock et al. 2001). To manage anthracnose, it is recommended by Vock (Vock et al. 2001) that: • • • • • • •

A program of fungicide sprays is maintained from fruit set to harvest. Good orchard ventilation and rapid drying of foliage is ensured by pruning lower limbs. Infected fruit is removed from the orchard. Dead twigs and branches are pruned out prior to flowering. Appropriate calcium and nitrogen levels are maintained to assist trees to resist infection. Insect pests are controlled as insect damage increases susceptibility. Fruit is handled carefully during harvest to avoid skin damage.

In addition to regular application of copper sprays to manage anthracnose, strobilurins (Amistar) is also recommended to be applied close to harvest and following extended wet periods (Dann et al. 2009). However, it must be used only in a manner consistent with recommended anti-resistance strategies. Avoidance of harvesting wet fruit is also recommended. Monitoring of damage levels from fruit spotting bug is particularly important following hot, windy conditions as this is when outbreaks tend to peak, particularly in known orchard “hotspots” (Drew 2007) . It is recommended that a spraying program is commenced when fruit damage levels reach 2% of sampled fruit and is continued at 14-28 day intervals until mid-April, or completion of harvest, if earlier (Vock et al. 2001). In the context of a warming climate, the need for close monitoring of all pests and disease becomes increasingly critical as biosecurity planning highlights that higher temperatures can allow insects to complete more lifecycles in a year and also allow insects to survive or thrive in locations significantly further south than their current ranges.

5.1.10 Mulching Research on mulching demonstrates that this management strategy can assist in mitigating many potential impacts of climate change. Eighty per cent of the avocado’s white feeder root system is in the top 45cm of soil and mulch (Vock et al. 2001). While mulches can increase the frost hazard and also increase fire hazard in hot dry conditions, the benefits of mulching include: • • •

Improves organic matter content and physical condition of soil (structure, porosity, aeration). Improves weed control. Enhances water penetration, soil water storage and conservation of soil moisture.


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• • • • • •

Regulates soil temperature and insulates soil from sun and wind. Stimulates feeder root development. Enhances micro-organism variety, abundance and activity which improves nutrient recycling, root health. Assists in suppressing problem fungus by supporting the growth of microorganisms that compete with or antagonize P. cinnamomi. Improves soil chemical characteristics: higher organic matter enhances the capacity of the soil to store and release nutrients (cation exchange capacity). Allows roots to bypass complex soil chemistry and access elements such as zinc and phosphorus directly from the mulch that otherwise can be bound in the soil.

It is recommended that trees are mulched at least until they are large enough to generate their own deep leaf litter. Mulch should be applied to a depth of 110 to 150mm and to a width of 75cm from the trunk of young trees and to 50cm beyond the drip line of older trees. Mulch materials should be course textured and freely draining such as wheat or barley straw, sorghum stubble or composted pine bark. It is also recommended to consider cover cropping while trees grow to harvestable age (Vock et al. 2001). Research conducted in a 6 year old ‘Hass’ orchard in South Africa demonstrated the benefits of mulching to address the problem of small fruit size, which is thought to be related to the premature death of the seed coat (Wolstenholme et al. 1998). The research tested the hypothesis that mulching could alleviate stress through enhanced root growth and root health, helping to maintain the functional integrity of the seed coat for as long as possible. The research found that mulching reduced the incidence of pedical ringneck by 47% and reduced seed coat degeneration by 39% (means of 3 seasons). Canopy temperatures were cooler by 0.5˚C to 6˚C in mulched trees. Mulching increased mean fruit mass by 6.6% over the three year trial (and by 12% in both of the first two seasons). There was an overall increase in fruit yield of 22.6% over the three year trial.

5.1.11 Nutrition Maintaining appropriate nutrition is an essential component of maintaining robust and resilient trees. Under most conditions the optimum soil pH for avocado orchards is 5.0-5.5, using the 1:5 soil/water test (Vock et al. 2001). Where soil pH is above 6.5, boron, copper, iron and zinc become less available and P.cinammomi becomes more active. Critical nutrients include: • Nitrogen (N), which is essential for growth and productivity. • Potassium (K), which regulates the water balance, influences water movements and controls the opening and closing of stomata. • Calcium (Ca), which, in high fruit concentrations may suppress development of anthracnose and other diseases, reduce chill injury and increase shelf life. Rootstocks may have a significant effect on calcium concentrations in fruit. • Boron (B), which is deficient in most avocado soils in Australia, particularly the light soils of Western Australia and high rainfall areas of subtropical eastern Australia. Avocados require higher amounts of Boron than other crops. Trees require frequent small applications throughout the year. Boron deficiency retards normal root growth.


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•

Zinc is required for production of enzymes and plant hormones and helps regulate water uptake. Zinc deficiency is common in Australian orchards (Vock et al. 2001).

Critical considerations regarding maintenance of optimum nutrition levels in the context of projected climate changes include: •

•

Monitoring leaf and soil test results closely to check if heavy rain events are rapidly leaching nutrients out of the root zone or if elevated CO2 levels are driving an increased demand for, and draw on, nutrients. Monitoring temperatures as warmer temperatures may alter the timing of key phenological events, driving a need to shift the timing of fertilizer application.

5.1.12 Irrigation Tree stress caused by inadequate water supply results in: • • • • • • • •

Reduced fruit number and size, causing a reduction in yield of up to half that of well watered trees. Premature flowering when temperatures are too cool, causing poor fruit set and miniature cocktail sized fruits. Increased spring and early summer fruit drop. Premature death of seed coat which may reduce fruit size, especially if water stress occurs in first 6-8 weeks after fruit set. “Ringneck” (browning of fruit stalk) leading to smaller, poorer quality fruit and in some cases, may also cause cracks in fruit skin near stem. Reduced uptake of boron and calcium leading to poor fruit shape and internal quality. Increase in stem end rots. More rapid ripening of fruit (Vock et al. 2001).

The impacts on the tree of water stress may be long lasting. Significant water stress has been shown to trigger the development of tyloses (gummy blockages) in the xylem that restrict water movement and thus reduce transpiration. These restrictions appear to be permanent and normal water movement may not resume until new xylem has grown (Turner et al. 2001). To avoid water deficit stress and optimize the available water supplies, Vock et al. (2001) provide the following recommendations: • • • •

Keep the upper root zone moist through irrigation and mulching as 80% of the white feeder roots are found in the top 45cm. Maintain an open loose surface with good mulching to allow water to penetrate; avoid soil compaction. Maintain high organic matter in soils to help retain more water. Design, establish and maintain an optimal irrigation system: o Based on a sound understanding of the infiltration rates of the soils in the orchard. o Based on a reliable supply of good quality water. o Use soil moisture monitoring and irrigation scheduling tools to help identify when to irrigate and how much water to apply. o Delivery system that evenly provides what the trees need.


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Use high output, low pressure under-tree mini sprinklers that minimize misting. o In hotter, drier areas (such as Sunraysia), pulse irrigation techniques can be useful and overhead misting can delay the tree shutting down/closing stomata in dry windy conditions. o Irrigate sandy soils more frequently. Mounding may be useful. Mulching is critical to reduce soil evaporation, regulate soil temperature and inhibit weeds which compete for water resources. Mow interrow grasses/plant cover. Use windbreaks to help reduce water loss from foliage under windy conditions. Consider overhead misters for cooling and humidifying in hot, dry or windy conditions. o

• • • • •

Recommended water requirements for key production regions are presented by Vock et al. (2001) in Table 4. Table 4. Recommended water requirements for Avocado production regions (Source: Agrilink 2001)

Crop water use efficiency benchmarking carried out through the Queensland Rural Water Use Efficiency program confirms these crop requirements. Total crop water


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requirements for mature trees is noted as approximately 11-12 ML/ha. For the Sunshine Coast region of Queensland where there is an average effective rainfall of seven to eight ML/ha the efficient irrigation requirement is three to five ML/ha, allowing for inefficiencies and drainage losses. Critical tensiometer values are noted as 20-30kPa during peak crop requirements. An efficient irrigation system can support best practice yields of 15-25 t/ha on the sunshine coast (Growcom 2002c). For the Lower Burnett, where average effective rainfall is three to five ML/ha, the efficient irrigation requirement is five to seven ML/ha (Growcom 2002b). In the Upper Atherton Tablelands, the efficient irrigation requirement was found to be between 37.5ML/ha (Growcom 2002a). More recent agronomic recommendations, confirmed by grower experience, are that irrigation should be applied at tensiometer values of 12 kPa (Newett, pers. com.). Frequent irrigation or avoidance of water stress was found to be a major factor in determining avocado fruit size, particularly early sizing (Meyer et al. 1992). Aleemullah et al. (2001) confirmed the benefits of careful irrigation scheduling to avoid water deficit stress in avocados in the Mareeba-Dimbulah and Atherton growing regions. Using soil moisture monitoring techniques, successful avocado irrigators maintained a soil moisture reserve of 25-28mm in the active root zone to optimize productivity. Research by Vuthapanich et al (1995) demonstrates the benefit of avoiding water deficit stress in avocado. In an experiment on seven year old ‘Hass’ tress growing in a warm, humid subtropical climate, trees watered when tensiometer readings reached 20 kPA had twice the yield of trees watered at 70kPa. The more frequently watered trees yielded a high number of fruits which ripened more slowly. The value of enlarging the wetted soil volume to encourage root growth and, therefore, the trees’ capacity to take up water in severe climatic conditions of high temperature and low relative humidity was studied by Cantuarias et al (1995). In the experiment, two irrigation treatments were trialed, one applying water via one drip lateral line along the row which wetted 25% of the soil surface and another with five drip lateral lines parallel to the row line which wetted 75% of the soil surface. The treatment with the enlarged wetted soil volume displayed improved root growth, improved water uptake and allowed an increased transpiration rate under conditions of high evaporative demand, preventing canopy water stress (expressed by higher LWP and lower Tc). Sap flow monitoring is being trialed as a technique to assess tree stress in context of both drought and excessively wet conditions (Heath and Arpaia 2007). A good water supply and targeted irrigation practices have been identified as the only way to reduce damage in the orchard in very hot conditions with dry winds. Frequent irrigation, preferably as daily pulses at 2 hour intervals, is recommended. An additional 50% of the normal budgeted amount should be applied the day before an expected heat wave (Lahav and Whiley 2002). In the context of climate change and a potential increase in irrigation demand, growers may need to consider securing additional water supplies beyond current guidelines for irrigation requirements and also enhance their water access security and reliability. The case for increasing water supplies is strengthened by the recommended use of overhead sprinkler systems for evaporative cooling in avocado orchards during


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conditions of extreme heat, high winds and low relative humidity (Lahav and Whiley 2002). In California, an overheard spray system has been used to minimize stomata closure and shutdown of photosynthesis when temperatures reach 30˚C and relative humidity is low The system delivered 650 litres per hectare per minute (about 2 litres per tree per minute) and operated for about five minutes in every 30. Five minutes of this overhead irrigation achieved a cooling of the canopy of 10˚C. (Simon Newett, pers. comm.), (Hofshi 1998). Lahav and Whiley (2002) recommend overhead sprinkling to reduce air temperatures and increase relative humidity. Wetting the canopy also modifies leaf temperature more effectively than soil surface irrigation. Evaporative cooling using micro-sprinkler irrigation has been shown to be an effective tool for reducing fruit temperatures in other fruits also. Research on “Jonagold” apples showed that evaporative cooling reduced maximum fruit surface temperatures by about 8˚C and reduced visible sunburn injury by between 9 and 16% (Parchomchuk and Meheriuk 1996). Cooling did not appear to affect fruit size, colour or firmness. More recent research using “Topred Delicious” and “Mondial Gala” varieties in Spain also showed that micro-sprinkler irrigation reduced fruit and orchard temperatures, and that cooled fruit were larger, firmer and with higher soluble solid concentrations (Iglesias et al. 2002; Iglesias et al. 2005). Micro-sprinkler misting has also been researched in citrus orchards to decrease temperature and increase humidity (Garcia-Delgado et al. 2004). At ambient air temperatures above 36°C, misting can reduce air temperature by up to 5°C within the canopy. Intermittent misting at times of high temperatures increased fruit set and yield without apparent negative effects on fruit quality. Misting was most effective at 30°C, but the effectiveness of this treatment was reduced at higher temperatures (Garcia-Delgado et al. 2004), indicating that this strategy may be useful in a shortterm transitional context. Risks of using overhead sprinklers for evaporative cooling include the cost and quality of water used; the increased potential to spread phytophthora root rot in heavier soils; and potential increased anthracnose infection (Hofshi 1998). Increased risk of sodium and chloride damage to the leaves has also been identified, so overhead irrigation should only be practiced using water of low salinity (Lahav and Whiley 2002). The impacts of excessive water stress can include (Vock et al. 2001): • • • • •

Reduced soil aeration reduces tree vigour. Trees can die if roots are waterlogged for greater than 48 hours. Increased incidence and severity of Phytophthora root rot. Increased risk of nutrient imbalances. Under waterlogged conditions, some nutrient levels can become toxic. Increased leaching of nutrients from root zone (loss of fertiliser and pollution of groundwater).

5.2 Summary of management strategies to address climate change In order to respond to climate variability and climate change, growers should consider a mix of proactive and reactive adaptation strategies. Critical needs are to


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manage the risks of heat stress and put in place measure to prepare for both drought and excessively wet conditions. Overall management strategies that should be considered in a climate change context include: • • • •

•

• • • •

Use of climate and long range weather forecasting services. Increased emphasis on information driven adaptive management and the use of record keeping and information management and analysis systems. Increased emphasis on efficient irrigation systems and tighter irrigation management practices including monitoring, scheduling and maintenance. Increased emphasis on securing irrigation and cooling water supplies. o Accessing additional water entitlements if required (surface, ground water, on-farm storage). o Investing (financially and politically) in water supply security/reliability. o Maximising on-farm water use efficiency. o Minimizing evaporation or seepage from on-farm storage. Strong focus on soil health and structure management and surface protection including high organic matter content, high soil biodiversity and mulching.to address the risks of extreme hot spells, intense or prolonged rain events and prolonged drought events. Optimising free drainage in soils. Ongoing research into appropriate rootstocks and varieties to suit climate conditions. Continued strong emphasis on further developing pesticide, fungicide and integrated pest & disease management techniques. Strong focus on business planning and development of broader business strategies to spread climate risks, such as: o Diversification of property locations to spread climate risks, spread harvest seasons and optimizes investment in packing facilities o Consideration of most effective business structures to optimize adaptability.

A summary of the climate changes that are projected to occur in avocado production regions, the production impacts the changes may cause and the management responses that could be applied to adapt to climate changes are presented in Table 5. This table has been adapted and further developed from analysis presented by Howden et al. (2006).


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Table 5. Summary of possible climate changes, potential production impacts and management strategies that could be considered Projected climate changes Overall warming

Potential impacts on growth, production or quality • Fruit set may occur earlier and time to maturity may reduce • More active insect populations (both pest and beneficial)

Management responses / adaptation strategies • •

• •

Reduced diurnal temperature range

•

Reduced time of overlap between openings of male and female flower parts which may reduce selfpollination and fruit set in single variety plantings

• •

•

•

Higher night temperatures

•

Increased night respiration reducing • carbon allocation to fruit, potentially lowering fruit size and yield (especially •


Earlier harvest Apply harvest and post harvest management practices to manage heat and sunburn if harvesting in high temperatures Adjust marketing plans if harvest times shift significantly Increase emphasis on pest monitoring and proactive pest management strategies using an Integrated Pest Management approach Consider shift in production location Improve chances of pollination by taking measures to ensure adequate bee activity in orchard at flowering Plant pollinator varieties in blocks consisting of single varieties (especially blocks consisting of ‘B’ type flowering varieties such as Shepard and Sharwil) Maximise fruit retention when fruit set is low through strong focus on irrigation, nutrition, pest and mulch management More frequent use of plant growth regulators to improve fruit size Develop marketing strategies for

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Avocado genetics are under-exploited; great diversity exists amongst the three avocado races offering excellent potential for breeding new rootstocks and varieties better adapted to particular conditions and with better yield and quality. Strategies could also include exploiting existing varieties that are, for example, better adapted to warmer conditions (e.g. Shepard and Sharwil), and researching better rootstock/scion combinations.

Projected climate changes

Higher summer day maximum temperatures / increase in summer heat stress days

Potential impacts on growth, production or quality Hass) • Positive effect on flowering and fruit set in cooler or frost prone areas • May increase survival and infectivity of P. cinnamomi and disease may be active for longer periods of the year • Higher volumes of irrigation needed • Increased risk of summer fruit drop • Increased risk of sunburn • Increased tree stress, which may increase susceptibility to pests and disease • May increase incidence of fruit spotting bug, especially when conditions are hot and windy • May reduce period in which mature fruit can be stored on the tree

Management responses / adaptation strategies

•

•

•

•

•

•

•


small / lunchbox-sized Hass Increase emphasis on preventative strategies for fungal disease control

Better irrigation management achieved through more intensive moisture monitoring, more responsive scheduling, and where beneficial the use of different types of irrigation (e.g. pulse irrigation and irrigation directed at cooling the canopy with sprinklers) Consider ways to increase water supply and security (e.g. expansion of on-farm water storage capacity &/or purchase of additional water entitlements) Mulch to help maintain appropriate soil temperature, conserve moisture and improve tree health More effective P. cinnamomi control to ensure a full, healthy leaf canopy to shade fruit from sun exposure Apply sunburn protection products to fruit e.g. Screen DuoTM, bentonite etc Selective harvest of exposed fruit early in harvest season to minimize sunburn (already practiced in WA)

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Potential impacts on growth, production or quality

Management responses / adaptation strategies •

•

• Higher day and night temperatures in autumn and winter and fewer frosts

•

•

May increase pollination and fruit set in areas that are currently considered marginal because of low temperatures If night temperatures are too high in autumn, floral induction may be poor


•

•

Where possible adjust timing of pruning to minimize exposure of fruit to sunburn Increase monitoring for fruit spotting bug, implement integrated and new control measures Shorten the harvest period More frequent use of plant growth regulators to improve the small fruit size expected with high levels of fruitset Where flowering is sparse: • Improve levels of pollination by taking measures to ensure adequate bee activity in orchard at flowering • Plant pollinator varieties in blocks consisting of single varieties (especially blocks consisting of ‘B’ type flowering varieties such as Shepard and Sharwil) • Maximize fruit retention when fruit set is low through strong focus on tree health, irrigation, nutrition, pest and mulch management • Consider shift in production location

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Projected climate changes Increased chance of heat stress conditions in spring

Increased incidence of excessively wet periods, more intense rainfall events

Potential impacts on growth, production or quality • If night temperatures are too high during spring, fruit set may be adversely affected. • Flower desiccation • Pollination failure • Fruitlet abscission

• • • • • • •

Increased risk of P. cinnamomi infection Increased risk of anthracnose and other fruit rots Quality may be affected if there is prolonged rain during harvest Tree / fruit damage Soil water logging Greater susceptibility to fungal diseases and pests Increased opportunity for water harvesting


• •

• •

• • •


A higher level of irrigation management achieved by more intensive moisture monitoring, more responsive scheduling and, where beneficial, the use of different types of irrigation (e.g. pulse irrigation and irrigation directed at cooling the canopy with sprinklers) Consider shift in production location When selecting new orchard locations choose sites that have a greater depth of well drained soil and/or sites where superior drainage can be achieved through measures such as higher row mounding, and surface and subsurface drainage Improve existing drainage in the orchard Regular monitoring of root phosphonate levels and strict implementation of control measures. Increased use of recommended mulching practices Achieve optimal soil conditions e.g. pH 5.5 and high soil calcium levels Monitor soil moisture more closely and improve irrigation and nutrient management, compensating where necessary for nutrients leached by excessive rainfall

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Potential impacts on growth, production or quality

Management responses / adaptation strategies • •

•

• • • Increased incidence of storm and cyclone events

• • •

Tree damage or loss Fruit drop Fruit damage

• •

• Increased incidence of drought conditions and drier spring weather

• • • •

Reduced fruit size (especially in Hass) Increase in fruit drop especially in spring and summer Reduced tree vigour Inadequate moisture in spring may


• •

Use of P. cinnamomi resistant / tolerant rootstocks Well-managed anthracnose control measures including a full program of fungicide sprays and good orchard hygiene Selection and use of rootstocks that produce elevated levels of antifungal compounds and produce fruit with a higher calcium:nitrogen ratio (e.g. Velvick) in order to reduce fruit susceptibility to anthracnose Always apply recommended postharvest fungicide to fruit Use rootstocks better adapted to wet conditions Increase on-farm water storage capacity and maximise harvest of runoff water May require re-location Well designed windbreaks using carefully selected species or artificial materials Adopt canopy management strategies that favour a smaller, more robust tree Be able to supply more irrigation when required Improve micro-management of water with better moisture monitoring and irrigation scheduling

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Potential impacts on growth, production or quality result in lower yields, smaller fruit size and poorer quality (the latter due to impeded uptake of calcium in the critical first 6 weeks after fruit set • Fruit grown under restricted moisture conditions will ripen more rapidly


•

•

•

Increased CO2 levels in the atmosphere

• •

Increase in yield Lower nutrient levels in fruit

•

• •

•


Install more effective and water efficient irrigation systems, e.g. drip irrigation if appropriate, and adopt more effective and efficient irrigation scheduling practices Consider ways to increase water supply and security (e.g. through on-farm water storage &/or purchase of additional water entitlements) Use mulch to help maintain appropriate soil temperature, conserve moisture and improve tree health Where conditions allow it, aim for smaller trees at higher densities as these are more efficient at using water (per tonne of fruit produced) Closer monitoring of plant nutrient levels and more responsive remedial action to maintain optimum levels in tree Select rootstocks with higher levels of nutrient uptake More frequent use of plant growth regulators to improve small fruit size expected with greater fruit set Conduct research to investigate the effect of higher carbon dioxide levels in combination with higher temperatures

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5.3 Key findings A range of management strategies are available to the avocado industry to respond to projected climate changes. Information-driven adaptive management will be essential in the context of climate change, underpinned by a strong emphasis on data collection, use of advanced information management, analysis and reporting systems, and regular reviews of management reports. The best opportunities for on-farm climate adaptation are in managing heat, particularly increased summer temperatures, through use of mulching, precision soil moisture monitoring and irrigation management. Optimising water use efficiency will be important. Projected climate changes will require a very strong focus on optimising free drainage in soils, maintaining soil health and implementing mulching strategies in order to provide protection from high temperatures and extremes in soil moisture. Ongoing investment in the research, development and trialling of alternate varieties and rootstocks has strong potential to support effective adaptation to changing climatic conditions. Projections of general warming over time in many current production areas also give added weight to the urgent need for research with a specific focus on the ‘Shepard’ variety, which is better adapted to warmer and drier conditions. The review of potential management responses to projected climate changes highlights the critical need to secure and probably increase water supplies and reserves for both irrigation and cooling. Changes to rainfall patterns and increased temperatures favouring insect reproduction will drive the need for ongoing efforts in pest monitoring and management. Projected climate changes that are difficult to manage through on-farm practices are those temperature changes that can affect initiation of flowering and pollination. Heavy rainfall during flowering and early fruit set would also be difficult to manage.


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6.0 The carbon emissions impact of avocado production As the agriculture sector has been identified as the second largest source of greenhouse gas emissions in the Australian economy, this project has provided a timely opportunity to conduct a preliminary estimate of the greenhouse gas emissions that are generated by avocado production. The project also provided the opportunity to further field test a greenhouse gas emissions estimating tool prepared for the horticulture industry. Greenhouse gas emissions can be generated on avocado farms and packhouses through activities such as driving tractors and vehicles, running pumps and machinery, operating cool rooms, using electricity and gas, application of fertilizers, waste disposal and composting. Cultivation of soils also generally releases greenhouse gases. Four avocado enterprises participated as case studies for the estimate of the industry’s contribution to greenhouse emissions. The case study farms were located in Childers, Bundaberg and Imbil in Queensland. Field visits were conducted 19-20 August 2010.

6.1 The concept of carbon footprints The measurement of the carbon emissions generated by a certain product or business has come to be known as a “carbon footprint”. The term “carbon footprint” has been used very loosely over recently years by governments, business and the media and so has come to meant different things to different people. While “carbon footprint” is the accepted terminology in widespread use, it is important to remember that it includes other greenhouse gases in addition to carbon dioxide (such as nitrous oxide and methane, as described in section 3), so it is more correctly described as a “greenhouse footprint”. Recently, the National Carbon Offset Standard (NCOS) has been introduced, and this provides a clear definition of carbon footprints and consistent, rigorous methodologies for calculating them (Department of Climate Change 2009). Under this standard, the carbon footprint for a business or activity is defined differently to the footprint for a specific product. The standard provides a specific methodology for determining each kind of footprint. The NCOS requirements for calculating the footprint of a business or organisation (for example, an avocado growing and/or packing enterprise) is reasonably straightforward but will vary with the emissions profile of the business. The recommended methodology for calculating the carbon footprint of a product (for example, a tray of avocados), however, is far more complex and requires a full life cycle assessment of the product in accordance with current international standards (such as ISO14040). Accordingly, in this project carbon footprints have been estimated for the avocado enterprise rather than for the actual avocado product.


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To calculate a carbon footprint for a business, the standard requires that an organisation must count (Department of Climate Change 2009): •

•

•

Direct emissions (scope 1) that occur within the business boundary, such as the burning of fossil fuels in tractors, pumps and machinery or volatilization of excess fertilizers. Indirect emissions (scope 2) from the use of electricity, heating, cooling or steam by the business but where the actual emissions occur outside the boundary of the business. Some indirect (scope 3) emissions that result from the activities of the organisation. For example, scope 3 emissions must include employees business travel, waste disposal and use of paper. Other scope 3 emissions should be considered if they meet other certain criteria, including whether they are believed to be large relative to scope 1 or 2 emissions or are deemed to be critical by key stakeholders. An organisation must document and disclose which scope 3 emissions have been included in its footprint calculations.

For calculating direct scope 1 emissions, the standard recommends the use of emissions factors derived from the National Greenhouse Accounts Factors (Department of Climate Change, 2008). Emissions factors provide simple formulae to convert energy consumed (eg. kWh of electricity or litres of diesel) into a quantity of emissions released. The standard also requires auditing of carbon footprint claims, particularly claims of carbon neutrality, by qualified and registered independent auditors.

6.2 Methodology for calculating emissions from avocado production The greenhouse gas emissions of the case study farms were estimated using a carbon footprint calculator, HortCarbonInfo. This calculator has been developed specifically for the horticulture industry by Peter Deuter of Agri-Science Queensland (formerly the Queensland Department of Primary Industries and Fisheries). The calculator aims to be compliant with the national standard and can be downloaded at no cost through the Growcom or HAL websites. http://www.growcom.com.au/_uploads/204551HortCarbonInfo_climatechange.xls http://www.horticulture.com.au/load_file.asp?f=/librarymanager/libs/162/Carbon%20Calc ulator.XLS In recent years, the calculator has been applied to a number of horticultural farms, largely in the vegetable industry. This project provided the opportunity to test its applicability to orcharding operations. The scope of the carbon footprint calculator is limited to on-farm emissions and, therefore, does not include emissions generated up or downstream in the value chain, other than from electricity generation. For the case study farms, the scope of the footprint was also limited to the orchard operation, and, as far as possible, excluded the emissions associated with avocado packing operations. This boundary was selected to


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ensure consistency of the results as some case study farms packed fruit through an offsite packing facility. The estimate also does not incorporate the carbon that may be sequestered on farm through the growth of orchard, windbreak, native and other trees or vegetation or in soils. Currently, footprint calculating tools do not attempt to account for on-farm carbon sequestration as there are so many factors that influence sequestration rates in soils and vegetation that it is difficult to develop rigorous estimation methods and accurate conversion factors. The estimate of greenhouse gas emissions was calculated based on farm data for one year. The case study farms provided farm records or close estimates from the 2009/2010 financial year for the following categories of data: • • • • • • •

•

Hectares of crop/orchard. Kilowatt hours of electricity used for all farming and packing operations. Litres of petrol, diesel and LPG used for any stationary operations such as pumps or generators. Litres of petrol, diesel and LPG used for vehicles on-farm such as tractors, utes or cherry pickers. Types and tonnes of fertilisers applied for the production of the crop and the nitrogen content of these fertilizers. Types and tonnes of animal manures applied for the production of the crop and the nitrogen content of these manures. Tonnes of waste disposed either on-farm or to municipal waste divided in the categories of paper and cardboard, green waste, concrete/metal/plastic/ glass and co-mingled. Kilograms of hydroflourocarbons used to fully charge any refrigeration systems used on farm.

The data was entered into the HortCarbonInfo Excel spreadsheet. Conversion factors provided by the National Greenhouse Accounts (Department of Climate Change and Energy Efficiency) are embedded in the spreadsheet, and automatically calculate the carbon emissions associated with each farm activity. A calculation of total emissions – the carbon footprint of the farm – was then generated.


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6.3 Results A summary of the carbon footprints for the four case study farms is provided in Table 6. The total emissions varied between about 26 tonnes and about 880 tonnes CO2-e over the 12 month period. In terms of emissions per unit area, the results range between 0.9 and 4.3 tonnes CO2-e/ha/year. The average across the four farms is 2.53 tonnes CO2-e/ha/year. Table 6 Carbon footprints of four sample avocado farms for one 12 month period.

Avocado Farm Carbon Footprint Results (tonnes CO2-e) Electricity Non-transport fuel Transport fuel Fertilizer Waste Refrigeration Total Farm Area (ha) Emissions (t / ha)

Farm 1 98.28 0.32 39.14 17.97 0.01 0.00 155.72 49 3.2

Farm 2 500.50 38.28 183.05 160.58 0.95 0.00 883.36 335 2.6

Farm 3 9.90 21.44 4.60 5.67 0.00 0.00 41.61 47 0.9

Farm 4 15.04 3.37 2.70 4.69 0.04 0.00 25.84 6 4.3

Detailed data from each farm is provided in figures 14-17.


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Figure 14. Detailed HortCarbonInfo results from Farm 1


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Figure 15. Detailed HortCarbonInfo Results from Farm 2


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The results indicate that the greenhouse gas emissions impact of avocado production is very low, between 0.9 and 4.3 tonnes per hectare. It should be noted that two of the case study farms were operating under a regime of limited use of synthetic fertilizers. Accordingly, a higher rate of emissions from nitrogen based fertilizers would be expected from more conventional farms. It should also be noted that the results for Farm 2 include some data from packhouse operations that could not be disaggregated from farm operations at the time of the field visit. From previous carbon footprinting work conducted in horticulture, it can be estimated that the annual emissions could be around 30% higher if the calculation had included the packing operations and cooling facilities. It can be seen that the make up of the carbon footprints for the case study farms is reasonably consistent. For each of the farms, stationary energy is the source of the greatest proportion of emissions, ranging between 61% to 75%. For three of the farms, electricity use is the main generator of these emissions, while for the other the source is diesel for pumps. Transport fuel was the source of 10% to 25% of the total emissions from the farms, while emissions from nitrogen-based fertilisers accounted for 12% to 18%. Emissions generated from waste, in most cases from pruning waste and reject fruit that was either composted on farm or disposed through the municipal waste system, was minimal from all farms. All participating farms indicated that minimal other waste was generated on the farm. The total emissions generated by the farms ranged from 26 to 883 tonnes of CO2 equivalents per year. To assess the significance of these results, it is useful to consider that an emissions level of 1000 tonnes of CO2 equivalents per year was discussed as a possible threshold for an agricultural enterprise to be required to participate in the proposed Carbon Pollution Reduction Scheme (CPRS), when the previous Labor government was deliberating whether or not to include the agricultural sector in the scheme. It is also interesting to compare the results from the four avocado case study farms with footprints determined using HortCarbonInfo in other horticultural enterprises. Table 7 presents results from four vegetable farms, though Farm 1 is not typical of vegetable production in Queensland as it includes a large area of grain crops that are produced in rotation with vegetable crops. Farm 2 is more typical of Queensland production. Table 8 provides results from the carbon footprint calculator applied to four fruit farms. Table 7 Carbon footprints for four Queensland vegetable farms. Vegetable Examples Electricity Non-transport fuel Transport fuel Fertilizer Waste Refrigeration Total

Farm 1 336.90 9.30 215.57 260.59 0.02 0.00 822.38

Farm 2 514.07 1.86 166.70 86.51 0.02 0.00 769.16

Farm 3 465.00 11.01 155.35 75.68 0.05 0.00 707.09


Farm 4 235.47 6.54 81.02 35.04 0.10 0.00 358.17

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Farm Area (ha) Emissions (t / ha)

550.00 1.5

106.00 7.3

95.00 7.4

52.00 6.9

Table 8 Carbon footprints for four Queensland fruit farms Fruit Examples Electricity Non-transport fuel Transport fuel Fertilizer Waste Refrigeration Total Farm Area (ha) Emissions (t / ha)

Farm 1 17.43 26.80 13.10 41.02 0.00 0.00 98.35 36.00 2.7

Farm 2 39.94 6.20 25.65 13.06 0.00 0.00 84.85 36.00 2.4

Farm 3 98.32 4.65 27.05 22.85 0.00 0.00 152.87 40.00 3.8

Farm 4 18.94 0.00 14.10 6.22 0.00 0.00 39.26 16.00 2.5

So compared to the avocado case study results, which ranged from 0.9 to 4.3 tonnes of carbon emissions per hectare, the typical vegetable farms ranged from 6.9 to 7.4 tonnes per hectare. The emissions from the sample fruit farms were lower, ranging from 2.4 to 3.8 tonnes of carbon emissions per hectare. The average carbon emissions per hectare per year of three banana farms estimated through HortCarbonInfo was 6.66 (http://www.horticulture.com.au/areas_of_Investment/Environment/Climate/threats_oppo rtunities_climate_change_banana.asp)

6.4 How carbon footprints can be used in the avocado industry The carbon footprinting process and the case studies conducted through this project could serve a number of purposes in the industry. For individual growers, the carbon footprinting process can be used to help identify areas where production efficiencies, and therefore cost savings, could be achieved. The HortCarbonInfo calculator can be accessed by any grower to generate an estimate of the carbon footprint of the business. The footprints of the four case study farms presented in this report offer growers a basis for comparison. Estimating, recording and monitoring the carbon footprint over time, establishes for a farm business a baseline against which changes can be measured. This information could assist growers to: • Prepare for the possible inclusion of carbon emissions accounting in approved supplier or environmental assurance schemes. • Position their business to explore and exploit any market opportunities that may emerge for low carbon or carbon neutral enterprises. • Develop carbon offsets products to offer on voluntary carbon trading markets. It should be noted that the National Carbon Offsets Standard (NCOS) requires independent auditing of footprint results before they can be used for marketing


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purposes, and full life cycle assessment footprinting must be used for carbon labeling of produce. If the avocado industry was interested in pursuing carbon footprinting for marketing purposes, the HortCarbonInfo calculator (or other customized calculators) would need to be audited and certified under the national standard. The avocado industry could consider promoting widespread use of the calculator amongst growers and encourage industry members to forward their results to Avocados Australia Ltd, enabling results to be aggregated into a larger, industry-wide data set for further analysis. From this data, key areas of emissions across a number of avocado farms could be identified, leading to the development of recommended management practices that could be implemented to reduce or avoid emissions. At an industry-wide scale, the footprint results from the four case study farms provide preliminary data that could be used in general promotion and communication indicating that avocado production appears to have a very low carbon impact. The results could assist the industry in any policy discussions with the federal government, positioning the industry as making a very minor contribution to national agricultural emissions. Other horticultural commodities have explored methods for estimating total industry emissions and average industry emissions per hectare or per million dollars of industry revenue (http://www.horticulture.com.au/areas_of_Investment/Environment/Climate/ threats_opportunities_climate_change_banana.asp). Estimates can be developed based on identifying the average emissions per hectare from a sample of farms using a carbon footprint calculator and then multiplying this figure by the total number of hectares under production in the industry. An alternate method is to use data obtained through the National Greenhouse Accounts. These estimates then allow comparison of the relative performance of various horticultural commodities and, more broadly, other agricultural industries.

6.5 Further development of carbon footprinting tools Ongoing refinements and inclusion of adjusted conversion factors will continue to be made to the HortCarbonInfo calculator. A new web-based carbon footprint calculator suitable for use in the vegetable industry was released in October 2010. The Vegetable Carbon Calculator (http://vegiecarbontool.com) was developed with the support of HAL and Woolworths. This calculator has similar data requirements to HortCarbonInfo and uses the same conversion factors; however, because it is an internet-based tool, it facilitates aggregation and reporting of industry data. Finally, there may be an opportunity to modify a footprinting calculator developed by Growcom for the production nursery industry and funded by the Nursery and Garden Industry Association (NGIA). This tool uses an ‘economic input-output approach’ to provide an estimate of a complete life cycle footprint without the onerous data requirements of a life cycle analysis. The user inputs the dollars spent in each area of the business, and conversion factors are applied to determine the carbon emissions that can be associated with expenditure in each area. The result is an estimate of the carbon


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footprint per unit of production. The growers who participated in this project indicated that they have access to the appropriate data, and Growcom has identified that it would be feasible to adjust this calculator for fruit and vegetable production businesses.

6.6 Key findings The HortCarbonInfo carbon footprint calculator provided an effective and simple means for estimating the carbon emissions of the case study farms. The carbon emissions from avocado production appear to be low (0.9 to 4.3 tonnes of carbon emissions per hectare per year) with the greatest proportion of emissions generated by stationary energy. Inclusion of packhouse data would provide a more accurate picture of carbon emissions associated with avocado production; however, even with packhouse operations included in the carbon footprint estimate, the avocado industry is likely to have a good case to promote itself as a low emissions industry. Carbon footprint estimations can provide useful management information, help identify production efficiencies and cost savings, and improved practices that lead to emissions abatement. Footprinting also facilitates preparedness for potential future market requirements or opportunities. Encouraging more widespread collection of carbon emissions information and collation at an industry level would provide valuable data for use by the industry in national policy development on abatement, pricing, and the development of carbon offsets markets. Pursuing further research to estimate whole of industry emissions would allow comparison of carbon impacts across horticultural commodities and the entire agricultural sector.


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7.0 Carbon labeling The development of carbon footprinting tools and calculators opens up the opportunity to add a new dimension to product marketing in the form of carbon labeling. Carbon product labeling is designed to raise consumer awareness of the emissions associated with the production of certain goods. By providing information on the relative emissions associated with different products, consumers can then use that information in their purchasing decisions. Carbon labeling also helps food producers and manufacturers to communicate their efficiency and low carbon status in an effort to gain market share with increasingly green consumers (Carbon Trust 2008; Edwards-Jones et al. 2009; Hogan and Thorpe 2009). Various eco-labels and environmental assurance certifications exist in the marketplace, so the emergence of carbon labeling raises questions such as: • •

Will political and community interest in climate change issues in Australia lead to consumer demands for carbon labeling for food? Would carbon labeling provide a cost effective contribution to carbon reduction efforts that benefits both producers and consumers?

7.1 International trends In the United Kingdom, carbon labeling has become quite strongly established since it was introduced in 2006, with supermarket chain, Tesco’s, playing a substantial leadership role. By July 2009, 60 companies were involved and around 2500 products displayed carbon labels, including many food products such as fruit juices, smoothies and crisps (Chan 2009). The global leader in carbon labeling is the UK government-backed Carbon Trust Footprinting Company (www.carbonlabel.com). The company has established a standard methodology for carbon footprinting and an on-pack logo, the “carbon reduction label” which shows a stylized black footprint with the product’s carbon emissions per unit written inside. The company has an independent certification arm, the Carbon Trust Footprinting Certification Company.

Figure 18. An example of The Carbon Reduction Label applied to laundry detergent.


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The businesses that choose to participate in the Carbon Reduction Label scheme commit to a comprehensive audit of greenhouse emissions along their supply chains and to further reduce emissions within two years (or lose access to the label). Competing carbon footprinting certification and labeling companies have also emerged such as “Carbon Counted” in Canada and “Climatop” in Switzerland (Hogan and Thorpe 2009). In the United States, Wal-Mart announced in July 2009 the development of a broader environmental and social sustainability labeling program for its products which it hopes will be adopted by other retailers (http://en.wikipedia.org/wiki/ Carbon_emission_label). Japan has also developed a government-approved carbon footprint labeling scheme, with labelled products on the market from April 2009.

7.2 Australian trends Australia’s two major supermarket chains, Coles and Woolworths, have not yet indicated an interest in introducing carbon footprinting or labeling. The Planet Ark company is managing the Carbon Reduction Label in Australia (Planet Ark 27 October 2010) and has announced that it will implement a carbon label on its products on Australian supermarket shelves from 2010, using the Carbon Reduction Label (Planet Ark 2009). The Aldi supermarket chain is the first Australian retailer to introduce the Carbon Reduction Label, which is limited to just one of its products, olive oil (Planet Ark 9 June 2010). While this initiative is a voluntary one, it may trigger other companies to adopt carbon labels in Australia to remain competitive. While Planet Ark claims to have independent research showing that 60% of Australians are more likely to purchase or use a product that displays a carbon reduction label, it seems unlikely that the major retailers will introduce requirements for carbon footprinting or labeling for fresh produce in the short to medium term. If Australian and international food companies or food processors follow the trend in the UK, however, growers may be drawn into farm-level carbon footprinting requirements for supply chain assessments that feed into processed or value added food product labeling. For the purposes of the Carbon Reduction Label, the carbon footprint of a product or service is the total greenhouse gases emitted during its life; this includes all emissions along the supply chain from production to final disposal, including the production of raw materials and transport etc. This Life Cycle Assessment of emissions is more complex and time consuming than the relatively simple process used in HortCarbonInfo and other footprinting tools.


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7.3 Assessing the potential costs and benefits of carbon labeling There are a number of reasons why the benefits of carbon labeling may be uncertain for both producers and consumers (Hogan and Thorpe 2009). Most importantly: •

The effectiveness of a labeling scheme depends on consumer perceptions of the reliability of the information presented and access to verification.

•

The administration and implementation costs may be high for labeling schemes that require complex methodologies and rigorous verification. These costs may be prohibitive for small independent producers.

Australian producers are also already familiar with the frustrations that arise from having to deal with a number of distinct and competing certification or labeling schemes. There is a possibility that this situation will play out again with carbon labeling, with exporting industries facing different labeling schemes with different standards and requirements in different international markets and the possibility that, at some point in the future, the major domestic retailers may introduce their own requirements into their approved supplier programs.

7.4 Key findings While carbon labeling has been introduced or proposed by retailers in the United Kingdom, Europe, Asia and North America, the labels to date have been applied only to processed foods, not fresh produce. Carbon labeling of food products in Australia is currently confined to one retailer and one product. Application of a carbon footprint label to products requires an assessment of the emissions generated throughout the full life cycle of the product. A standard methodology and certification scheme is available through the Carbon Trust, as well as other schemes that have been established. It is unlikely that carbon labeling will be implemented on fresh produce in Australia in the foreseeable future. There is some potential for carbon footprinting to become a requirement for growers supplying to processors and for retailers to incorporate carbon footprinting into approved supplier programs and assurance schemes; this is unlikely to occur in the short term. In order to prepare for these possibilities it may be useful for growers to consider estimating and recording carbon emissions information in their business record keeping system.


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8.0 Carbon markets and emissions trading 8.1 Options for addressing carbon emissions Governments across the world are considering the policy options that may drive significant reductions in carbon emissions. Most options are designed to put a price on greenhouse gas emissions. This addresses the failure of the current economic market to properly include the environmental costs of production (in this case, air pollution) into the price of products and services that generate greenhouse gas emissions. A review of available policy options has been conducted by the Australian Parliamentary Library (Nielson 2010).

8.1.1 Emissions trading schemes (ETS) An Emissions Trading Scheme (ETS) is a market-based approach which encourages businesses to reduce their carbon emissions by establishing a cost of carbon emissions. The major appeal of an ETS is that it offers businesses some flexibility in how they go about managing their emissions. The most common form of an emissions trading scheme is based on the “cap-and-trade” principle. Under this system, the government: • Identifies the business activities in the national economy that cause the majority of carbon emissions. • Introduces a limit (or cap) on the carbon pollution that can be collectively emitted by those businesses. • Issues a number of emissions permits equal to the cap (one permit allows one tonne of carbon emissions) and make a requirement that those businesses must hold permits for the greenhouse gases they emit. • Imposes heavy penalties on businesses that emit more than their permits allow. • Facilitates the establishment of markets that enable businesses to buy and sell emissions permits or emissions offsets. If a business has insufficient permits to cover its emissions, it can: • Reduce emissions. • Buy additional permits (at auction or from other businesses that have reduced their emissions). • Buy offsets for their emissions (e.g. carbon credits from agroforestry). • Any combination of the above. If a business has excess permits, it can sell them on the open market where the price is set by supply and demand. A central permit register must be established by government to underpin the emissions permits market and facilitate trade. The decision on which is the best option for a particular business will be based on the relative costs of reducing the emissions from their activities (which may require investing in new equipment or technology) and the current cost of emission permits or carbon offsets.


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8.1.2 Carbon tax A carbon tax is an environmental tax on emissions of greenhouse gases. By implementing a carbon tax, a government creates a penalty for businesses that emit carbon pollution. This provides an incentive for businesses to reduce their emission levels and for consumers to adjust their consumption. The tax also has the effect of enhancing the competitiveness of low – emission businesses in the economy, such as renewable/clean energy products or power suppliers. In its 2007 submission to the then Prime Minister's task force on emissions trading, the Productivity Commission said a carbon tax could offer an effective transitional step in pricing greenhouse gases and in cutting greenhouse gas emissions, due to its administrative simplicity. In theory, the rate of tax should accurately reflect the cost of the environmental damage caused by the carbon pollution. In practice, however, the rate of tax would more likely be determined by other factors such as a level acceptable in the community, the rate required to change consumer behaviour towards the emissions targets, or government revenue targets. Governments can commit to making a carbon tax revenue-neutral by re-investing the monies raised into other carbon pollution reduction initiatives. Proponents of a carbon tax suggest that it offers an economically efficient way to introduce a price signal into the economy and encourage investment in low emission or carbon reducing options, it can be phased in and stepped up on a transparent scale over time, does not require the generation of offsets that need to be verified, nor the establishment of a complex market system. A disadvantage of a carbon tax is that it cannot guarantee a particular level of emissions. Unlike an ETS which sets an emissions level and allows the market to establish the cost, a carbon tax sets a price and allows businesses to optimise their emissions based on numerous factors.

8.1.3 Direct regulation Regulatory instruments can specify either a technology standard or a performance standard (Nielson 2010). Using a performance standard approach, the government could introduce regulations that make it unlawful to emit carbon pollution in excess of certain levels. The regulations could be applied selectively to certain industries or could be applied across the economy, using a threshold of emissions levels. Establishing the desired emissions levels or “baselines” for individual industries may be problematic. A regulatory approach must be underpinned by emissions measurement and monitoring systems and robust compliance, enforcement and penalty systems. A system based on regulation is likely to be inflexible, administratively complex and expensive.


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8.1.4 Incentives An incentives approach would involve the government providing assistance to businesses to reduce carbon emissions and/or support low-emissions products and services to become more competitive. Forms of assistance could include financial incentives, subsidies, tax rebates, funding programs, voluntary agreements and investment in research and development. To be effective, incentives approaches should be underpinned by clear emissions reductions targets and monitoring, reporting and independent evaluation systems.

8.1.5 Do nothing The government could choose to not intervene in any way in the economy to influence the rate of greenhouse gas emissions and instead allow market forces and consumer preferences to respond. The risk of this option is that the market response can be expected to be very slow and the lack of government action would be judged as noncompliance with Australia’s international obligations under the Kyoto Protocol. Nations that have implemented carbon emissions reduction policies would be highly likely to impose border adjustments such as tariffs or other trade barriers on products imported from Australia to account for the different production costs their domestic producers face as a result of higher carbon prices.

8.2 The proposed Carbon Pollution Reduction Scheme Following the 2007 federal election, the Rudd government was believed to have a mandate to progress with the design and implementation of a carbon emissions trading scheme, based on a cap-and-trade approach. The government also had bi-partisan support for this approach. Significant policy development ensued, culminating in the proposed Carbon Pollution Reduction Scheme (CPRS) legislation in 2009. The CPRS legislation, however, failed to win the support of parliament and the Rudd government eventually announced that it would not present the legislation again until after the 2010 election. While the CPRS legislation was never passed, related legislation was enacted to establish a broad framework for greenhouse gas emissions monitoring and management, including the Renewable Energy Target and the National Carbon Offset Standard. As further detailed below, the 2010 election resulted in a minority Labor Government with a commitment to introduce some kind of carbon pricing mechanism, though not necessarily an emissions trading scheme.


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Although the CPRS has been shelved, this report retains the detailed review of the proposed CPRS and the assessment of its possible implications for the avocado industry as this is the best indication of what a final emissions trading scheme in Australia may look like. All of the available economic modelling and impact assessments are based on the proposed arrangements under the CPRS. Much of the analysis should be transferable to reviewing emerging policies or redesigned schemes. Furthermore, it is likely that the supporting and complimentary legislation (such as the Renewal Energy Target, the Agricultural Offsets Scheme and the National Carbon Offset Standard) will remain largely unchanged. An overview of each component of the proposed CPRS, as outlined in the 2008 White Paper (Australian Government 2008) and the proposed legislation, is therefore, presented below.

8.2.1 International targets, frameworks and rules To optimise its effectiveness, any national scheme for carbon emissions trading should be consistent with international frameworks. The proposed CPRS aimed to achieve this. The United Nations Framework Convention on Climate Change (UNFCCC) provides the basis for a coordinated international response to climate change. Under the convention, a regular series of Conferences of the Parties (COP) provide a forum for international negotiations regarding emissions targets, recognised abatement technologies and actions, accounting rules, and financial assistance for developing countries. Prior to the Conference of the Parties (COP15) in Copenhagen, Denmark, in December 2009, there was general optimism that the negotiations would lead to legally binding emissions targets and refined accounting rules. These are essential to maintain international solidarity for climate action and for individual countries to achieve real progress in the formulation of domestic policies. The Copenhagen negotiations, however, failed to finalise key details for binding targets and methodologies. This failure took the momentum from domestic policy development in many countries, including Australia. COP16, held in Cancun, Mexico, in November-December 2010, also resulted in little real progress in many areas. However, the renewed positivity and energy in the negotiations have restored faith in the UNFCCC process and could lead to more vigorous domestic policy development. The Kyoto Protocol is a treaty created under the UNFCCC which came into force in 2005. It provides the structure under which national governments make binding commitments to carbon emission reduction targets and it also sets out common rules for emissions accounting, abatement and trading. According to the treaty, developed countries must have fulfilled their emissions reduction commitments by the end of the first commitment period (2008–2012). By ensuring our national trading scheme complies with international rules, emissions abatement in Australia can be recognised by the international community and our trading scheme can link to international markets. Increasing the effective size of the market through these international linkages should reduce the cost of permits for Australian


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businesses. International consistency across national schemes should also help to limit distortion in global trade. The Kyoto rules, however, are extensive, complex and imposed significant constraints on the design of the CPRS, some of which would have disadvantaged the agriculture sector. Relevant issues for agriculture include: • Carbon accounting rules – One concern for the agriculture sector is that the Kyoto accounting rules recognise greenhouse gas emissions from livestock and fertilisers but not the carbon sequestration that occurs as crops and pastures grow – this means that the carbon emissions attributed to Australian agriculture are effectively gross rather than net emissions. These rules are currently due for discussion and re-negotiation. • Carbon offsets – must meet the international principles of additionality, permanence, verifiability and measurability, independent audit and registration (described in section 8.3).

8.2.2 National Accounting System One of the first requirements that flow from Australia’s commitments under the Kyoto Protocol is one of monitoring and reporting national carbon emissions. A range of mechanisms are being put in place by the Australian Government to do this. Usually, emissions are estimated rather than actually measured, again following internationally agreed rules. The National Greenhouse Gas Inventory, managed by the Australian Government Department of Climate Change, is the central process for compiling data on carbon emissions. Data is drawn from a range of sources, including the National Greenhouse and Energy Reporting System (NGERS), the Australian Greenhouse Emissions Information System (AGEIS) and the National Carbon Accounting System (NCAS). This data is then presented annually in the National Greenhouse Accounts, which is the key mechanism for domestic and international reporting. All components of the measuring and reporting system conform to international guidelines. Australian businesses that meet certain emissions or energy production thresholds are now required by law to report data on their emissions to NGERS. No horticultural enterprise would be large enough to trigger a requirement to report to the system; however, the government encourages voluntary reporting and will trial voluntary agricultural reporting in 2011. Agricultural and horticultural emissions are estimated through the National Carbon Accounting System (NCAS). NCAS accounts for emissions from agriculture and other land-based industries using an integrated system that combines land cover data (collected via satellite), with other data on land management practices, climate and soil. It then applies greenhouse gas accounting tools and ecosystem modelling to estimate emissions. The National Carbon Accounting Toolbox (NCAT) is a free software tool derived from NCAS that allows land managers to estimate changes in emissions resulting from land management actions, such as soil cultivation, fire management and fertiliser application.


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8.2.3 Emissions target Supported by improved data on national emissions, the Australian Government sets and, over time, re-assesses targets for reducing emissions. The current national target, as outlined in the Kyoto Protocol, is to limit emissions in the 2008-2012 period to an average of an 8% increase in carbon emissions from 1990 levels. It is expected that Australia will achieve this target. The long-term national target is to reduce carbon pollution by 60% of 2000 levels by 2050. The current short term target is a 5% reduction of carbon pollution below 2000 levels by 2020. Should other major economies make significant commitments in subsequent international climate negotiations, the Australian Government would raise its short term reduction target to 15-25%. The flexibility in targets is based on the recognition that variation in national targets may lead to market and trade inequalities which may place Australian exporting industries at a competitive disadvantage.

8.2.4 Coverage and thresholds Coverage refers to the sectors of the economy that will be required by law to participate in an emissions trading scheme. The CPRS proposed to include the stationary energy (eg. electricity generators), transport, fugitive emissions, industrial processes and waste sectors. Any business in a covered sector that emits more than 25 000 tonnes of carbon dioxide equivalents per year would have been required to participate in the scheme. Those businesses that meet the participation threshold would have their emissions monitored, reported and audited and would have been required to surrender one permit for each tonne of emissions they produced. Around 1000 business enterprises were to be included in the scheme when it commenced in 2011. Together, these businesses are responsible for around 75% of Australia’s total emissions.

8.2.5 Exclusion of agriculture The agriculture sector is responsible for about 16% of Australia’s carbon emissions - the second largest contributor in the economy behind stationary energy (figure 1). In early stages of the CPRS design process, the Government indicated that it was exploring options for including agriculture in the CPRS. However, the Government announced in November 2009 that agricultural businesses would be excluded from the CPRS indefinitely (Australian Government 2009). It was determined that the large number of small agricultural enterprises and difficulties in accurately accounting for agricultural emissions made inclusion of the sector unworkable.


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The government emphasised, however, that significant emissions reductions will need to be achieved in the agriculture sector if Australia is to meet its long-term national emissions targets. Accordingly, the Australian Government is considering alternate strategies for driving these reductions and has identified an agricultural offsets scheme as one option. The government announced in 2009 that it would commissions a review by the Productivity Commission in 2015 to assess whether the Australian agricultural sector is at World’s best practice mitigation and examine potential measures to achieve further emissions reductions in the sector. While these potential measures have not been identified, it is reasonable to assume that the choices will include the list of policy options identified earlier in this report (such as a carbon tax specifically for agriculture, regulations and/or incentives).

8.2.6 Cap The national emissions target becomes a practical reality when the government sets a cap that limits the total emissions that will be permitted per year from the businesses covered by the scheme. The scheme cap determines the number of permits (Australian Emissions Units) that the Government would issue each year. To provide businesses with some information on likely future caps to assist planning, guidance was to be provided through the announcement of ‘gateways’ or ranges within which future scheme caps would lie up to 10 years in advance.

8.2.7 Permits and permit trading Under the CPRS process, businesses covered by the scheme could emit carbon pollution at any level, so long as they had sufficient permits for their emissions. Businesses covered by the CPRS would have been required to surrender a permit for every tonne of carbon emissions that they produced in that year. Each year, the Australian Government would issue permits equal to the cap – so if the cap for a particular year was 100 million tonnes of carbon dioxide equivalent (CO2-e), then 100 million emissions units (permits) would be issued for that year. Under the proposed CPRS, firms would have competed to purchase the number of permits that they required through an auction process. A small proportion of permits were to be administratively allocated as a form of transitional assistance to some businesses (particularly those that are emissions intensive and exposed to international trade competition). It was proposed that in the first year of operation of the CPRS (originally 2011), the price of permits would be set at $10 each. The price of permits were also to be capped for the first five years of the scheme’s operation, starting at $40/tonne cap, rising at 5% in real terms per year until after the 2015/2016 compliance year. In subsequent years, the auction process would allow the market to establish the price for permits.


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After the permits auction had distributed the available permits amongst the covered businesses, a secondary trading market would operate. Businesses that could not (or chose to not) limit their emissions to a level covered by the permits they acquired in the auction could seek to buy permits from other businesses in the scheme through the trading market. Participants in the Australian CPRS would have been able to purchase and surrender Kyoto-compliant permits from other international emissions trading schemes. However, CPRS permits could not be sold into international trading schemes. Permits could also be banked for future use, adding further flexibility for participating businesses.

8.2.8 Offsets Carbon offsets are another means for businesses to account for their emissions or profit in the carbon market. Offsets can be traded in the secondary carbon market. Under the proposed CPRS, there were to be two forms of offsets – those recognised as contributing to Australia’s emissions abatement commitments under Kyoto and those that did not. A business covered under the CPRS could use only Kyoto-compliant offsets. These offsets could be generated only by businesses that were not covered by the CPRS. The other forms of offsets will be discussed further below. Tradable Kyoto-compliant carbon offsets are certified by government as an activity that reduces greenhouse gas emissions or enhances the removal of greenhouse gases from the atmosphere, relative to a business-as-usual baseline. A recognised offset becomes a credit and can be used in the same way as a permit in the CPRS. An offset credit would have the same value or price as a CPRS permit. In theory, covered businesses would be able to use credits to offset their emissions from the commencement of the scheme. Calford et al. (2010) notes that “The critical difference between Kyoto compliant CPRS offsets and non-CPRS offsets will be the prices at which they can be sold. Kyoto compliant CPRS offsets, by definition, will be worth the same as a CPRS permit. The value of non-CPRS offsets will be determined by the relative supply and demand in the voluntary offsets market. It is likely that, at least initially, the voluntary market will be relatively small. Unless an international market is found, domestic demand may not be sufficient to induce significant investments in generating non-CPRS offsets.”

8.2.9 Agricultural offsets Because the agriculture sector was to be excluded from the CPRS, there may have been opportunities for agricultural enterprises to gain credit for works or practices implemented on-farm to reduce their emissions. These credits could then be sold on the CPRS carbon trading market or the voluntary carbon market. Abatement of emissions from livestock, manure, fertiliser use, burning of savannas, burning of agricultural residues and avoided deforestation could be eligible for carbon credits.


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The availability of offsets credits, however, will be conditional on the development of internationally-acceptable methodologies for determining the emission reduction achieved by an activity and defining the baseline scenario against which a reduction can be measured. Australia will need to develop these methodologies domestically because current international methods cannot be applied in the Australian context. Further details on potential abatement activities and methodologies will be discussed in section 8.3.

8.3 Agricultural offsets and the carbon market International efforts to reduce greenhouse gas emissions have lead to the development of carbon markets. In Australia, a voluntary market already operates for the trade of carbon offsets, driven by companies who seek to position themselves or their products as carbon friendly or even carbon neutral. If an emissions trading scheme is introduced, a new regulated carbon market will develop specifically for the trade of carbon permits and Kyotocompliant carbon offsets credits. The voluntary and regulated markets are usually quite distinct, and it is important to understand the differing opportunities that each market may offer agricultural enterprises.

8.3.1 The National Carbon Offset Standard The voluntary carbon market brings together businesses that are seeking to voluntarily reduce or offset their greenhouse gas emissions with businesses who can supply verifiable greenhouse emissions reductions or carbon sequestration. Up until recently, the voluntary carbon market operated with little or no regulatory oversight. This has impacted on the capacity of the market to maintain credibility amongst market participants (buyers and sellers of carbon credits), consumers and the general public. Reduced credibility has a negative impact on demand and the price of offsets in the market. To address this, and to ensure the voluntary market increasingly operates in a manner that complements the objectives of any potential emissions trading scheme, the Australian Government has developed a regulatory framework to guide and monitor the operation of the voluntary market. The Australian National Carbon Offset Standard (NCOS) was released in November 2009 (Department of Climate Change 2009) and came into effect in July 2010. The standard is voluntary and provides guidelines for: • eligible carbon offsets for the voluntary carbon market, • how to rigorously calculate the carbon footprint of an organisation or product, Climate change and the Australian avocado industry

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•

•

transparent recording of the carbon footprint, measures taken to reduce emissions and the amount reduced, and the carbon offsets that have been used; and auditing carbon footprints and carbon offsets claims.

The standard has been developed to ensure the voluntary carbon offset market operates properly, and that carbon offsets sold in the market provide legitimate emissions reductions or carbon sequestration. It is hoped that this will ensure that consumers can have confidence in carbon offsets and products that claim to be carbon neutral. The standard will be further strengthened by an administrative framework and regulations that will be released over the next year or so, which will include the definition of specific processes and reporting requirements. At present, the standard actually provides little guidance on the kinds of projects or practices that could generate offsets. Emissions sources currently not counted toward Australia’s obligations under the Kyoto Protocol target and, therefore, eligible for the generation of domestic voluntary market offsets under the Standard are (Department of Climate Change 2009): • • •

Forest management, in forests established before 1990; Revegetation (establishment of woody biomass that does not meet forest criteria); and Cropland and grazing land management (net greenhouse gas emissions from soil, crops and vegetation), which can include bio-sequestration through soil carbon and biochar.

It should be noted that these categories of potential carbon credits may change as a result of international negotiations that redefine emissions abatements that can be counted towards Kyoto targets. Also, there is still substantial work to be done to develop robust methodologies to account for and verify these forms of carbon credits. A number of established criteria will be applied to determine whether a methodology or project is eligible under the Standard. These include: • •

•

•

Additional – The offset must not be achieved through “business-as-usual” activities or to meet a regulatory requirement. Permanent – The abatement activity, strategy or project must permanently reduce the emission of greenhouse gas. The party providing the offset may be required to hold insurance against unintended events that could cause the carbon reduction to be reversed (such as fire). Measurable and verifiable – Methodologies used to quantify the amount of emissions reductions generated must be robust and based on a defensible scientific method. Emissions abatement is generally calculated by subtracting the actual emissions from an estimate of baseline or business-as-usual emissions. The estimate or modelling methodology used must be internationally acceptable. Transparent – Stakeholders must be able to examine relevant information, including methodologies, data sources, monitoring arrangements and assumptions.


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• •

Independent audit – The relevant information must be audited by an independent and qualified third party. Registration – The generated offset units must be registered and tracked in a registry.

The significance of the additionality requirement should not be underestimated. Using a strict definition of additionality, it is difficult to identify an on-farm action that would be classed as additional. For example, if improving soil carbon is known to improve productivity, then this action could be considered to be a part of efficient farm management and not necessarily a result of the carbon market. An important implication of the additionality requirement that directly affects avocado growers is that the carbon sequestered in growing orchard trees is not an eligible carbon offset. The voluntary carbon market has been operating in Australia and internationally for some years. There are many companies offering brokering services for carbon offset products based on carbon sequestration from various soil and forest management practices. The nature of the offset market is likely to change significantly over time. “In 2012, for example, the agricultural offset market is likely to be small, chiefly due to issues surrounding the development of robust methodologies for agriculture …In the longer run, many of these problems will have been addressed, and technology will also have improved. Therefore, it is reasonable to expect that the uptake of mitigation technology induced by the proposed offsets schemes will be significant in the long run.” (Calford et al. 2010)

8.3.2 The Carbon Farming Initiative The Carbon Farming Initiative (CFI) aims to give farmers and landholders easy access to both the voluntary and international regulated carbon markets. The CFI brings agricultural offset opportunities into one regulatory framework, regardless of whether the generated offsets are fully compliant with Kyoto regulations or not. The CFI was a 2010 election commitment of the Gillard Government and is currently in the consultation stage. Much of the detail is similar to the agricultural offsets scheme that accompanied the final version of the shelved CPRS. As proposed, the CFI will include a number of components, including: • • •

A carbon crediting mechanism. Funding to fast-track the development of eligible methodologies. Information and tools.

The CFI is designed to complement the NCOS and potential offset projects must meet the same eligibility criteria required by the NCOS (additional, permanent, measurable, transparent etc.). The list of potentially eligible abatement activities include: • •

Reforestation and revegetation. Reduced methane emissions from livestock.


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• • • • • •

Reduced emissions from fertiliser. Manure management. Sequestration in agricultural soils. Savanna fire management. Avoided deforestation. Burning of crop residues.

However, further work is required to determine the eligibility of these abatement activities and projects. Detailed methodologies will need to be developed and submitted for approval by a Domestic Offsets Integrity Committee. Until these methodologies are finalised and approved, it is difficult to assess the full range of available opportunities. For horticultural producers, it would appear that abatement from improved fertiliser management offers the best opportunity, though most horticultural enterprises are likely to be too small in scale to generate sufficient emissions reductions. Improved fertiliser management activities that could be recognised include: • • •

improved timing of fertiliser application to match plant requirements improved fertiliser quality (slow release or coated forms) improved placement of nitrogen fertiliser.

Although the additionality criteria is still required, a more relaxed or flexible interpretation may be applied in the CFI, opening possibilities for a greater range of activities and projects. The government has committed $50M for detailed research and on-farm testing of emissions reduction activities that can lead to the development of agricultural carbon offsets eligible to be recognised as carbon credits under the NCOS and CFI (Australian Government 2009). As the Carbon Farming Initiative is still in the consultation stage and further refinements are expected, we recommend that the avocado industry monitors the development of this scheme as it may result in important opportunities for avocado growers.

8.4 The role of agriculture in emissions trading and carbon markets With the release of the Carbon Farming Initiative, the Australian Government has identified a very clear role for agriculture: to remain outside of any emissions trading scheme and pursue on-farm emissions abatement and/or carbon sequestration that can be sold into either the regulated or voluntary carbon markets. At this point, the opportunities for agricultural industries to participate in this initiative are unclear given that the eligibility of the many potential abatement activities is yet to be determined. The opportunities for horticultural enterprises, in particular, appear to be very limited. For example, the intensive use of relatively small areas of land results in little under-utilised land being available for forestry and revegetation projects. The


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current lack of rigorous estimation methods for emissions reductions from fertiliser management and soil carbon sequestration also limit opportunities in the near future. A remaining obstacle to participation in the CFI concerns the cost-effectiveness of the eligible abatement activities. In addition to the establishment costs of initiating an abatement project (planting trees, new equipment etc.), there will be significant compliance costs associated with project approval, measurement, verification and auditing. The ratio of the total project cost to the potential value of the generated offsets is impossible to calculate at this time. Further detail is required on the range of eligible abatement activities, the likely compliance costs of participation in the CFI, and of course, the expected carbon price. Given these uncertainties, we recommend that the avocado industry should: • • •

monitor the development of eligible abatement methodologies. monitor the development of the regulatory frameworks for the NCOS and CFI that will set the requirements for monitoring, verification and auditing. once these details are finalised, conduct detailed analyses of the cost effectiveness of the abatement activities relevant to the avocado industry.

There is also a role for agricultural industry bodies and research agencies to investigate options to contribute to the development of more accurate accounting methodologies that would improve the measurement of net agricultural emissions. In the same vein, there is substantial room to explore options for more direct reporting of net emissions. This would also facilitate an improved standing to influence international standards of accounting and reporting – and seek to shift these to be more favourable to Australian agriculture (both in terms of assessing agriculture’s contribution to greenhouse emissions and also the sector’s opportunities to generate credits and offsets).

8.5 Developments in emissions policy following the 2010 federal election With the renewed interest at the federal government level in tackling greenhouse gas emissions through some form of carbon pricing mechanism and ongoing developments in voluntary carbon markets, there is value in the avocado industry maintaining a watching brief on developments in this area.

8.5.1 Australian regulatory trends The process of developing and implementing policies and economic reforms to reduce greenhouse gas emissions in Australia has been fraught. After the Rudd Government shelved the proposed CPRS legislation indefinitely in mid2010, both major political parties went to the August 2010 federal election with policies rejecting or delaying emissions pricing.


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The election, however, resulted in a hung parliament. Frustration in the electorate regarding the lack of progress by the two major political parties on delivering effective responses to climate change and emissions reduction was cited as a major reason for the result. The Labor Party has now formed a minority government with the support of three independent members and a member from the Australian Greens Party (which will also hold the balance of power in the Senate from July 2011). Development of policies and strategies regarding greenhouse gas emissions will now begin afresh under a new Minister for Climate Change and Energy Efficiency, Greg Combet. To progress the development of emissions abatement and carbon pricing policy options, the government has: • •

•

•

Formed a multi-party climate change parliamentary committee and defined its structure, authority and terms of reference. Commissioned an update of the Garnaut review to take into account developments of the past two years. The update will also seek input from an expert group on the status of real and implicit carbon pricing in China and other developed countries. A public forum for scientists and economists on the social impacts of climate change and climate change mitigation is also proposed. Established a roundtable each for business and non-government organizations (NGOs) to discuss carbon pricing matters and provide input to the development of government policy. Announced that a Climate Change Commission will be established.

The multi-party climate change committee is made up of the Prime Minister, Deputy Prime Minister and the Minister for Climate Change and Energy Efficiency along with two members of the Australian Greens Party and two representatives from the independent members of parliament. The Coalition has declined the offer of two places on the committee. The committee is supported by four independent expert advisers - Professor Ross Garnaut, Professor Will Steffen, Mr Rod Sims and Ms Patricia Faulkner. The committee will consider mechanisms for introducing a carbon price including a broad based emissions trading scheme, a broad based carbon levy, a hybrid of both, and economy wide and sector based approaches. It will also consider issues such as coverage, international linkages, implementation issues, assistance measures for households and businesses and review provisions. The committee is also intended to play a role in establishing community consensus for action on climate change. The committee will report to Cabinet through Minister Combet with a range of possible policy positions. The roundtables will meet monthly, or as required, until the end of 2011. The business roundtable is co-chaired by the Deputy Prime Minister and Treasurer, Wayne Swan, and the Minister for Climate Change and Energy Efficiency. The Minister for Resources and Energy, Martin Ferguson, is also a member. The National Farmers Federation has a representative on this roundtable.


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The NGO roundtable is co-chaired by the Minister for Climate Change and Energy Efficiency, Greg Combet, and the Minister for Sustainability, Environment, Water, Population and Communities, Tony Burke. The Minister for Agriculture, Fisheries and Forestry, Joe Ludwig, is also a member. The Citizens’ Assembly, proposed by the Labor Party during the election campaign, will not proceed as the climate change committee believes there are adequate alternate mechanisms now in place. Deliberations will be influenced by: • • •

Minister Combet and Prime Minister Gillard’s view that significant consultation, negotiation and consensus building is required. The need to incorporate the views and policies of the Australian Greens Party and the independent members. The rapid pace of international investment in the “low carbon economy” driven by corporate initiatives and government incentives, even in the absence of a new international treaty on climate change.

It is likely that the government will aim to identify some kind of mechanism that can be implemented by 2013 to place a price on carbon emissions. The minister has identified this issue as one of his top three priorities and a majority of members of the House of Representatives support the introduction of a carbon price. Options that are currently being canvassed include: • • • • •

A carbon tax, possibly as an interim measure or possibly as an ongoing element in a mix of measures. An emissions trading scheme (ETS) that covers only the energy sector, in order to stimulate critical investment in low emission or renewable energy supplies. A modified CPRS. An alternate, simplified, broad-based ETS. Land use initiatives and agricultural carbon offsets scheme are likely to feature in the policy mix.

Any substantial indication of the approach that may be implemented is unlikely before mid-2011, and it will take considerably longer for sufficient detail to emerge to allow a thorough analysis of the implications. It is likely that the initial mechanism that is implemented will be an interim measure or a step in a staged approach towards a more comprehensive system. There appears to be stronger support for a market-based approach for the longer-term, comprehensive scheme than for a tax or regulatory-based approach. Minister Combet has indicated that the detailed work that went into designing the CPRS will inform the development of alternate mechanisms. Should the new government opt for an ETS, it is likely that it would include higher emissions reductions targets and less compensation to emitting industries than the CPRS, due to the influence of the Australian Greens Party. At this stage, it is not possible to speculate on which sectors of the economy may be covered under a new scheme, and the debate on the inclusion or exclusion of the agriculture sector may need to be revisited in the context of any proposed new arrangements.


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Options for a carbon tax are even less clear. At this point, the tax rate and the included sectors are unknown, although there is speculation that a tax rate of $20-25 might apply to emissions from electricity generation and liquid fuels. As with an emissions trading scheme, this will inevitably result in increased input costs for avocado growers but it is currently impossible to estimate the scale of those impacts. A possible approach may be to introduce an interim carbon tax that is phased out in favour of an emissions trading scheme after several years, or a hybrid approach where difference sectors are subject to different policies.

8.5.2 International trends Despite high expectations, the 2009 Copenhagen conference (COP15) failed to make significant progress towards a new international agreement to replace the Kyoto framework. The most recent UNFCCC conference (COP16 in Cancun) also made little real progress in setting firm emissions targets or developing an international framework for emissions reductions. The Cancun conference, however, did result in a new agreement on the process, and this positive outcome has restored confidence in the UNFCCC negotiation process. Some commentators suggested that a lack of progress in Cancun would have jeopardised the United Nations facilitated approach and led to alternative processes being established. Alternatives include regional multi-lateral agreements which operate in the absence of any global framework or an alternative international process facilitated through the World Trade Organisation. An international treaty is not likely to take shape until the end of 2011 at the earliest (COP17 in South Africa). In spite of slow progress towards international agreements on emissions reductions targets, significant initiatives are being pursued by individual national governments such as China, Japan and New Zealand. Significant shifts in corporate investment are also occurring as businesses recognise the opportunities in the emerging low emissions economy. This policy development and investment should accelerate given the renewed confidence in the UN process following Cancun.

8.6 Key findings In this section, we have summarised the evolution of policies and mechanisms governing emissions mitigation and carbon trading. In addition, we have attempted to provide some insights into possible developments in domestic policies that may have an impact on the avocado industry. One clear conclusion is that the development of domestic climate policy in Australia is still in a state of flux. While policy development has been renewed following the 2010 federal election, important details on the broader policy mechanisms are still clouded in


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uncertainty. What will be the emissions mitigation target? Will the preferred mechanism to achieve emissions reductions be a tax, an emissions trading scheme, a combination of both, neither or something else altogether? Which sectors will be captured by the policy mechanism? One area where there has been some significant development is the attempt to provide some regulation and structure to the carbon market. The National Carbon Offset Standard and the Carbon Farming Initiative provide some important guidance on how agricultural industries may participate in the carbon market. However, more details are required before we can fully evaluate the potential opportunities. For example, the industry requires more information on the range of eligible abatement methodologies and the likely costs related to participation. Only then will the industry be able to analyse the true cost-effectiveness of carbon offset projects. The avocado industry should maintain an active watching brief on the Australian political debate and be prepared to participate in policy and technical discussions as they progress. While there currently appear to be few genuine opportunities for avocado producers within carbon offsets initiatives, the industry may benefit from maintaining an interest and involvement with the development of carbon offsets rules and methodologies, particularly around soil carbon management. In preparation for potential future opportunities, it would be useful for the avocado industry to build a more extensive database of carbon footprints for avocado orchards and pack houses. The industry could do this by promoting the widespread use of the HortCarbonInfo calculator and encourage growers to submit their results to a central database, managed, for example, by Avocados Australia Ltd. This would provide the industry organization with credible information on the estimated carbon emissions impact of avocado production for use in public and policy discussions. There would also be value in the industry maintaining a watching brief on carbon labelling. While it seems unlikely to be introduced on a stand-alone basis in supermarkets, some components of emissions reporting or energy efficiency requirements may filter into existing certification and quality assurance schemes.


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9.0 Potential implications of carbon emissions trading and carbon markets for the Australian avocado industry While the Carbon Pollution Reduction Scheme (CPRS) will not be implemented in its originally proposed form, it is expected that a carbon pricing mechanism of some sort will be introduced into the Australian economy by the Gillard government. Current discussions of taxes or alternate emissions trading arrangements indicate that the financial penalty for emitting greenhouse gases would probably commence at an initial cost of around $25 per tonne of CO2 equivalents, increasing over time. This is fairly consistent with the price structure that had been proposed under the CPRS. This section presents an analysis of the potential implications of carbon emissions trading, and in particular, the proposed CPRS, for the Australian avocado industry. While most of the economic research that is reviewed is largely based on the parameters of the previously proposed CPRS arrangements, the review should still provide the avocado industry with a reasonable indication of the implications of introducing a carbon price. The implications of emissions trading are explored under a number of themes, including financial and business impacts, implications of emissions estimation methods, the likely influence of emissions trading on the mix of rural land uses and the relative competitiveness of rural industries, and the business implications arising from carbon offsets. As new models for carbon pricing are developed and debated in the coming year or so, new economic impact assessments will need to be conducted. As few of the reports completed to date adequately assessed the impacts for horticultural industries, there is an opportunity for the industry to strongly advocate for more effective inclusion of horticultural industry data and case studies in subsequent studies.

9.1 Financial and business impacts A number of reports have attempted to assess the potential economic impacts of the CPRS on the agriculture and forestry sectors. Very little research has yet been conducted to adequately investigate impacts for the horticultural sector. All but one of these economic impact assessments were also conducted prior to the government’s announcement of the agricultural carbon offsets scheme. Due to the exclusion of the agriculture sector from the CPRS, there will be no direct costs associated with participation in the scheme; no agricultural or horticultural enterprise will be required to purchase carbon emissions permits. The introduction of the CPRS, however, will drive increases in input costs for all agricultural enterprises, particularly fuel, electricity, fertilisers, chemicals and freight (Ford et al. 2009; Jiang et al. 2009; Tulloh et al. 2009). In a review of the on-farm


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impacts of the CPRS prepared for the Rural Industries Research and Development Corporation (RIRDC), Jiang et al. (2009) concluded that a permit price of $25 per tonne would increase fertiliser and chemical costs by about 3%, and freight costs by about 2%. The National Greenhouse Accounts contain information on the emissions that result from various activities, including the generation of electricity and burning of liquid fuels. Using this information, it is possible to calculate general ‘rules of thumb’ for estimating the cost impact on other farm inputs resulting from a price on emissions. For example, for each $10 per tonne increase in the cost of emissions: • •

the cost of electricity will increase by about 1 cent per kWh, and the cost of petrol will increase by about 2.5 cents per litre.

In all reports to date, the economic impacts on horticultural enterprises were less significant than for all other agricultural industries (Jiang et al. 2009; Keogh and Thompson 2008; Tulloh et al. 2009). The available modelling suggests that the introduction of the CPRS could have a relatively small financial impact on horticultural enterprises. Jiang et al. (2009) found that farm cash income could fall by around 1% for horticulture at a carbon price of $25/tCO2-e; modelling also suggested that for a tropical fruits enterprise in 2020 compared to business as usual the CPRS could lead to a 0.59% decrease in production, a 0.47% decrease in gross value of product and a 1.54% decrease in farm income. Modelling reported by Tulloh et al. (2009) suggested wheat and other crops could face total on-farm input cost increases of 1.3% in 2015. Slightly more significant impacts have been suggested by Keogh and Thompson (2008). Modelling of impacts for 2030 assuming a $20/t permit price in 2010 increasing at 6% per annum suggest a 2% decline in farm cash margins for the citrus enterprise case study and a 3.2% decline for a vegetable enterprise. Keogh and Thompson’s (2008) analysis suggests that “larger-scale farms and farms which are able to achieve higher rates of productivity growth are likely to be better able to absorb the impact of ETS policies”. Overall, the available data suggests that as an uncovered sector, horticultural enterprises may not experience major financial impacts from the introduction of the CPRS. The most recent investigation of the effects of the CPRS on agricultural industries was completed by the Australian Bureau of Agricultural and Resource Economics (Calford et al. 2010). This report is based on the most recent policy details of the CPRS, including the agricultural offsets scheme, and presents a much more optimistic outlook for agricultural industries. The report concludes that the inclusion of the agricultural offsets scheme should have a positive net effect on agricultural industries through increasing productivity and decreasing net production costs. It is likely that the scheme will offer greater benefits to the industries that are currently emissions intensive (such as meat and dairy), as those industries have more scope to reduce emissions and generate offsets. Of course, the conclusions also come with some important caveats; many of the potential actions for generating offsets require rigorous methodologies to be developed before they can be exploited. Furthermore, the conclusions are dependent on Climate change and the Australian avocado industry

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assumptions of domestic and international policy settings and future carbon prices, all of which may vary.

9.2 Impact of baseline data, emissions estimation methods and monitoring frameworks The agriculture sector has been highlighted as the second largest source of the nation’s total greenhouse emissions and the Australian Government has emphasised its expectation that the agriculture sector should make a significant contribution to efforts to achieve long term emissions reductions targets. Accordingly, all agricultural industries, including horticulture, will be under significant government and public scrutiny regarding their efforts to reduce emissions and contribute to carbon sequestration. Yet the systems in place to estimate emissions from agricultural land uses and monitor changes in them should be a matter of some concern for the agricultural sector. “Current international greenhouse accounting rules mean that Australia’s greenhouse emission inventory recognises gross greenhouse emissions from livestock and fertilisers, but does not recognise the sequestration that occurs as crops and pasture plants grow. The result is that the greenhouse emissions attributed to Australian agriculture are effectively gross rather than net emissions” (Keogh and Thompson 2008). As outlined earlier, the National Carbon Accounting System is used to estimate agricultural emissions and this is coordinated by the Australian Government Department of Climate Change. It may be in the agriculture sector’s interests to consider options for the development of improved emissions estimation methodologies and for playing a more direct role in monitoring and reporting its emissions. Agricultural industry organisations might also consider putting greater effort into influencing the development of international carbon accounting rules. Keogh & Thompson (2008) argue that it will be critical to “ensure that the methods used to estimate agricultural greenhouse emissions are robust, and appropriate for Australian conditions. Small changes in emission estimation methodologies can result in substantial changes in net emissions, especially for larger-scale farm businesses, and this could in future have a very significant financial impact on that business”. While this comment was made in the context of the debate around including or excluding the agriculture sector from the CPRS, it is also relevant in the context of agricultural enterprises seeking to participate in carbon offsets markets. The accuracy of emissions estimations methodologies and their capacity to operate at finer scales also has implications for the potential for horticultural enterprises to pursue projects aimed at generating carbon credits. This will be discussed further below. There may be value in the avocado industry investigating any potential benefits in participating in the trial of voluntary agricultural reporting to the National Greenhouse and Energy Reporting System (NGERS).


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9.3 The relative competitiveness of agricultural and forestry industries Some analyses have attempted to assess how the introduction of the CPRS and an agricultural offsets scheme could influence the mix of land uses in rural Australia by affecting the relative competitiveness of agricultural and forestry industries. Economic modelling of this issue, however, is very difficult due to the range of factors that need to be considered so few firm conclusions can be drawn at this time. In their analysis, Calford et al. (2010) suggest that over time, the most emissions intensive industries (such as red meat and dairy) will have the greatest opportunities to generate carbon offsets, which perversely could increase their share of agricultural production at the expense of agricultural industries with lower emissions. Keogh & Thompson (2008) note that under medium or high emissions price scenarios, the combination of high demand for carbon sink forests and declining farm profitability may drive substantial conversion of grazing land to forestry plantations or environmental plantings. However, Calford et al. (2010) suggest that the opportunities to develop carbon offsets in both agriculture and forestry would limit land use change out of agriculture. It seems unlikely that the dynamics between broadacre agriculture and the forestry sector would pose significant influence on the area of land dedicated to horticulture. As a general rule, the revenues generated per hectare by horticulture on suitable land compared to broadacre and forestry industries mean that horticultural land would only be a risk of conversion if the value of carbon offset credits skyrocketed. A strong growth in carbon offsets forests, however, could restrict the availability of suitable land for horticultural expansion.

9.4 Emerging business opportunities and requirements from carbon offsets While the announcement of an agricultural offsets scheme may appear to offer opportunities for agricultural and horticultural enterprises to generate new income from carbon credits, the finer detail suggests the opportunities may be extremely limited. This is due to: • Poor baseline information on the existing carbon emissions from horticultural production. • Limited available information about the kinds of activities or projects that could be implemented on horticultural enterprises to reduce emissions or sequester carbon. • The need to custom-build internationally acceptable methodologies for measuring the change in carbon emissions from the implementation of abatement or sequestration activities. • The anticipated cost of measuring, monitoring, reporting, verifying, and possibly insuring emissions abatement or sequestration to create recognised carbon credits.


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•

• • •

The limited scale on which carbon credits could be generated by individual horticultural enterprises, and therefore the need to broker a bundling of efforts across many enterprises (which adds cost and further administrative complexity). The requirement for “additionality” which effectively excludes offsets resulting from activities that may be considered “business as usual”. The “permanence” requirements which may impact on the long term operation of the enterprise. The low price of carbon emissions permits (and therefore carbon offsets credits), at least in the first five years of the operation of the CPRS.

There is significant uncertainty regarding the options for generating carbon credits in the agriculture sector. While emissions abatement from improved fertilizer management has been identified as an opportunity, Calford et al. (2010) note that, “Many of these technologies and practices are not likely to be implemented on a large scale in Australia because they are too costly, or apply only to small-scale activities or may not be judged to be ‘additional’; in the sense that their uptake is not induced by the policy”. Increasing carbon sequestration by increasing soil carbon is generally considered to offer the most promise for agriculture. However, there is a high degree of uncertainty surrounding the ‘potential’ volume of soil sequestration available in Australia and on the ability to realise that potential (Sanderman et al. 2010). Furthermore, it is difficult to ensure the permanence of soil carbon sequestration (Calford et al. 2010). Generating, verifying and trading carbon credits is likely to be costly. “It is tempting to assume that an agricultural offsets scheme would involve significantly lower measurement and administration costs than including agriculture directly in the CPRS. However, both methodologies involve significant measurement and administration costs. A methodology will be needed for measuring the baseline for each type of project that is allowed to generate offsets, and emissions from all projects will need to be monitored” (Calford et al. 2010). It is essential that avocado growers understand that carbon credits cannot be generated simply from the growth of trees in the orchard. To be recognized, an activity must be additional to the business as usual case. The avocado industry will need to consider the value of pursuing research into on-farm emissions reductions options and their measurement through the $50M research and development funding boost. From a policy and advocacy perspective, the avocado industry may need to be proactive in communicating the low potential for its growers to generate carbon credits, given that the Australian Government has positioned the agricultural offsets scheme as both a means for agriculture to defray the financial impacts of the CPRS and contribute towards national emissions reductions targets. At an individual business level, growers should be aware that over the coming years, there may be an increasing value in monitoring and recording carbon emissions. In the short term, this data may assist with internal assessment of issues and management needs such as energy or fertiliser efficiency opportunities. In the longer term, the data may provide useful baseline information to investigate any opportunities around


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generating carbon credits and also to be well positioned to respond to any future government or market requirements for carbon reporting or labelling.

9.5 Key findings Climate policy in Australia is still in the early stages of development. At the time this report was completed, there was no clear indication of whether the likely policy would involve an emissions trading scheme, a carbon tax or some other mechanism to apply a price to carbon emissions. However, any new policy that features a carbon price will result in higher farm input costs (eg. fuel, electricity, chemicals and fertiliser). Unfortunately, without more detail on the mechanism and carbon price, it is impossible to calculate the precise effects on input costs and farm profitability. Modelling of impacts of the proposed CPRS on farm income suggested that the cost increases would be relatively small for horticultural businesses (perhaps in the range of 2-3% at $25 per tonne), especially when compared to other agricultural industries. In some cases, growers may be able to minimise these costs by increasing attention on energy, fertiliser and production efficiency. The Carbon Farming Initiative will allow growers to participate in carbon markets, possibly negating the increased input costs or even providing new profitable business opportunities. However, there is insufficient detail on potential eligible activities and the projected costs to assess the cost-effectiveness of any activities that may be available to avocado growers. The avocado industry should monitor further developments in climate policy and the Carbon Farming Initiative and investigate new opportunities as they arise.


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10.0 Conclusions and critical industry issues Through this project, a broad range of matters related to climate change have been assessed, including: • • • • •

critical climate parameters for avocado production, climate change projections for avocado production regions, management strategies that could be applied to mitigate against or adapt to climate changes, the carbon emissions impact of avocado production, and developments in the areas of carbon emissions trading, carbon offsets and carbon labelling, and their implications for the industry.

A number of climate thresholds and optima have been identified from the literature for successful avocado production, largely for the ‘Hass’ variety. Unfortunately, for many commercial Australian avocado varieties there has been insufficient research from which to assess critical climate parameters. This is particularly the case for the ‘Shepard’ variety. Based on the climate mapping and modelling that has been done for this project and the review of other climate change reports, it is clear that warming will occur in all Australian avocado production regions at least to some extent by 2080. South-west Western Australia and New South Wales appear to be facing the lowest risk of experiencing climate changes that could impact on avocado production. The Atherton Tablelands, coastal North Queensland and areas within southeast Queensland appear to be the production regions most at risk of damaging climate change. Projected increases in spring or summer temperatures may impact on flowering, pollination, early fruit development or fruit maturation in some areas by 2020. The climate of parts of Tasmania is projected to become more suitable for avocado production, suggesting that there may be opportunities for industry expansion in these areas if soil conditions are also appropriate. The review of possible management strategies that could be applied to respond to climate change suggests that increased temperatures and rainfall intensity could be managed reasonably effectively through practices such as improving soil drainage capacity, irrigation, evaporative cooling and mulching. Information-driven adaptive management has also been highlighted as an essential element in monitoring and adapting to climate change. The strong genetic diversity of the avocado species should also provide opportunities for the industry to identify and develop alternate rootstocks or varieties that may be better suited to future climatic conditions in current production regions. Climatic conditions may increasingly favour the ‘Shepard’ variety, lending further weight to the need for targeted research into this variety to determine its optimum temperature range, the best pollinator varieties and other critical issues. While these findings appear generally positive for the avocado industry, a number of matters have been identified through the review of climatic needs that require further analysis. Changes in winter or spring temperature regimes and rainfall patterns have the potential to cause significant disruption to critical phenological stages, including floral initiation, flowering, pollination and fruit set, and early fruit development. There are


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limited on-farm management practices that are available to address these issues. Projected changes to night minimum temperatures and to diurnal temperature ranges in winter and spring need to be assessed at finer regional scales, which was beyond the scope of the existing project. It is strongly recommended that further detailed modelling be undertaken by specialist climate scientists to assess critical climate parameters for specific varieties in key production regions. It may be useful to prioritise those regions identified through this project as most at risk. An assessment of the carbon emissions impact of four case study farms has been conducted and indicates that the emissions from the avocado industry are likely to be very small. Currently, there is no regulatory requirement for avocado growers to estimate, record or report their carbon emissions. The value of carbon footprinting, instead, lies in the identification of possible production efficiencies and cost savings, and in developing credible information that can support industry promotion of its low emissions status. Investment in the measurement of actual carbon emissions and sequestration in horticultural operations would be valuable. The review of trends in carbon labelling suggests that this area has been slow to develop in Australia. The industry, however, should be aware of the potential for carbon accounting to become incorporated into approved supplier or quality assurance schemes so it may be useful to widely communicate to growers the availability of carbon footprinting calculations tools. While there has been significant development of frameworks for carbon offsets and trading, there currently appears to be few genuine opportunities for avocado producers within carbon offsets initiatives. The industry may benefit from maintaining an interest and involvement with the development of carbon offsets rules and methodologies, particularly around soil carbon management. During the course of this project, it became apparent that further research, development and extension work will be required to maximise the adaptive capacity of the Australian avocado industry. Some recommendations include: •

•

• •

•

Trial the use of AVOMAN to track changes from year to year of key phenological events and to identify any adjustments that are occurring in phenological events driven by changes to climate. Commission additional detailed modelling of critical climate thresholds at particular growth stages, including both temperature envelopes and changes to rainfall patterns. Targeted research on the ‘Shepard’ variety which may grow in importance under altered climatic conditions. The development of new varieties and rootstocks that are better suited to future climate conditions should be a high priority. Should West Indian varieties be found to be better adapted to future conditions, marketing strategies may also be needed to facilitate consumer acceptance of fruits with novel characteristics. It may be useful for the industry to collate information on management practices that could be applied to reduce carbon emissions, especially with respect to soil health, fertiliser application and energy efficiency within current farming systems.


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• •

•

Emphasis should be on identifying practices which simultaneously achieve productivity, sustainability, adaptability and abatement. Closely monitor developments in climate policies and offset methodologies. The horticulture industry as a whole should invest in improved methods of measuring, rather than merely estimating, emissions and sequestration in horticulture. Engage with policy makers and the media to improve the position of horticulture in the emerging policy framework and trading mechanisms.


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11.0 References Ainsworth E. & Long S. (2005) What have we learned from 15 years of free air CO2 enrichment (FACE)? A meta analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytologist 165, 351-72. Aleemullah M., Clark D., Panitz M. & Geddes R. (2001) Benchmarking best irrigation management practices in avocado. In: Australian & New Zealand Avocado Growers Conference 2001, Bundaberg, Queensland, Australia. Allen A. (2009) State of the industry: Australia. In: 4th Australian and New Zealand Avocado Growers Conference (ANZAGC09), Cairns, Australia. Argaman E. (1983) Effect of temperature and pollen source on fertilization, fruit-set and abscission in avocado (Persea americana Mill.). The Hebrew University of Jerusalem, Israel. Aurambout J.-P., Finlay K., Luck J. & Sposito V. (2006) The impacts of climate change on plant biosecurity. Victorian Government Department of Primary Industries, Werribee, Victoria. Australian Government. (2008) Carbon Pollution Reduction Scheme: Australia's Low Pollution Future. White Paper. p. 435. Australian Government, Canberra. Australian Government. (2009) Details of proposed CPRS changes 24 November 2009. p. 18. Australian Government, Canberra. Bergh B. O. (1967) Reasons for low yields of avocados. California Avocado Society 1967 Yearbook 51, 161-72. Bower J. P. (1988) Pre- and Postharvest measures for long term storage of avocados. South African Avocado Growers’ Association Yearbook 1988 11, 68-72. Bower J. P. & Cutting J. G. (1988) Avocado fruit development and ripening physiology. Horticultural reviews 10, 229-71. Bower J. P. & Cutting J. G. M. (1987) Some factors affecting post-harvest quality in avocado fruit. In: Proceedings of the World Avocado Congress I pp. 143-6, South Africa. Bower J. P., Wolstenholme B. N. & de Jager J. M. (1977) Incoming solar radiation and internal water status as stress factors in avocado, Persea Americana (mill.) cv Edranol. In: South African Avocado Growers’ Association Proceedings of the Technical Committee pp. 35-40, South Africa. Buttrose M. S. & Alexander D. M. (1978a) PROMOTION OF FLORAL INITIATION IN FUERTE AVOCADO BY LOW-TEMPERATURE AND SHORT DAYLENGTH. Scientia Horticulturae 8, 213-7. Buttrose M. S. & Alexander D. M. (1978b) Promotion of floral initiation in Fuerte avocado by low temperature and short daylength. Sci. Hortic. 8, 213-7.


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Calford E., Gurney A., Heyhoe E. & Ahammad H. (2010) The effects of an emissions offsets scheme on Australian agriculture. In: Issues insights p. 26. ABARE, Canberra. Cantuarias T., Tomer E. & Cohen Y. (1995) Improving avocado tree water status under severe climatic conditions by increasing wetted soil volume In: World Avocado Congress III pp. 196 - 204, Israel Carbon Trust. (2008) Product carbon footprinting: the new business opportunity. Experience from leading companies. p. 32. The Carbon Trust. Chan Y. (2009) Australia to launch carbon labels in 2010: UK Carbon Trust takes labelling scheme Down Under. In: Business Green.com. Cure J. D. & Acock B. (1986) Crop responses to carbon dioxide doubling: a literature survey. Agric. For. Meteorol. 38, 127-45. Cutting J. G. M. (1993) The cytokinin complex as related to small fruit in "Hass" avocado. South African Avocado Growers’ Association Yearbook 1993, 20-1. Dann L., Coates L., Smith L., Pegg K. G., Dean J. & Cooke T. (2009) Impacts of fruit disease management on quality. In: 4th Australian and New Zealand Avocado Growers Conference (ANZAGC09), Cairns, Australia. de la Vina G., Pliego-Alfaro F., Driscoll S. P., Mitchell V. J., Parry M. A. & Lawlor D. W. (1999) Effects of CO2 and sugars on photosynthesis and composition of avocado leaves grown in vitro. Plant Physiol. Biochem. 37, 587-95. Denner F. D. N., Kotze J. M. & Putterill J. F. (1986) The effect of temperature on spore germination, growth and appressorium formation of Colletotrichum gloeosporioides and Dothiorella aromatica. South African Avocado Growers' Association Research Report 9, 19-22. Department of Climate Change. (2009) National Carbon Offset Standard. Australian Government, Canberra. Downer J., Faber B. & Menge J. (2002) Factors affecting root rot control in mulched avocado orchards. HortTechnology 12, 601-5. Drake B. G., GonzalezMeler M. A. & Long S. P. (1997) More efficient plants: A consequence of rising atmospheric CO2? Annual Review of Plant Physiology and Plant Molecular Biology 48, 609-39. Drew H. (2007) Improving the management of spotting bugs in avocados. Horticulture Australia Ltd. Duvenhage J. A. (1993) The influence of wet picking on post harvest diseases and disorders of avocado fruit. South African Avocado Growers’ Association Yearbook, 77-9. Edwards-Jones G., Plassmann K., York E. H., Hounsome B., Jones D. L. & Mila i Canals L. (2009) Vulnerability of exporting nations to the development of a carbon label in the United Kingdom. Environmental Science & Policy 12, 479-90.


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Ferguson I., Volz R. & Woolf A. (1999) Preharvest factors affecting physiological disorders of fruit. Postharvest Biol. Technol. 15, 255-62. Ford M., Gurney A., Tulloh C., McInnis T., Mi R. & Ahammad H. (2009) Agriculture and the Carbon Pollution Reduction Scheme (CPRS): economic issues and implications. In: Issues insights p. 30. Australian Bureau of Agricultural and Resource Economics (ABARE), Canberra. Gafni E. (1984) Effect of extreme temperature regimes and different pollinizers on the fertilization and fruit set processes in avocado. The Hebrew University of Jerusalem, Israel. Gallo L., Siverio F. & Rodriguez-Perez A. M. (2007) Thermal sensitivity of Phytophthora cinnamomi and long-term effectiveness of soil solarisation to control avocado root rot. Ann. Appl. Biol. 150, 65-73. Garcia-Delgado M. A., Zermeno-Gonzalez A., Lee-Rodriguez V., Castro-Meza B. I., Briones-Encinia F. & Aguirre-Bortoni M. D. J. (2004) Effect of misting on air temperature and humidity and its relationship with fruit set and yield of navel orange. Agrociencia 38, 643-51. Gazit S. & Degani C. (2002) Reproductive biology. In: The Avocado: Botany, Production and Uses (eds A. W. Whiley, B. Schaffer and B. N. Wolstenholme) pp. 101-34. CABI Publishing, Oxon. Growcom. (2002a) Benchmark - irrigating avocados in North Queensland. Water for Profit fact sheet. Growcom, Brisbane. Growcom. (2002b) Benchmark - irrigating avocados in the Lower Burnett. Water for Profit fact sheet. Growcom, Brisbane. Growcom. (2002c) Benchmark - irrigating avocados on the Sunshine Coast. Water for Profit fact sheet. Growcom, Brisbane. Heath R. L. & Arpaia M. (2005) Avocado tree physiology – understanding the basis of productivity. Continuing project: year 4 of 5. In: California Avocado Research Symposium pp. 87-119, University of California, Riverside. Heath R. L. & Arpaia M. (2007) Assimilation productivity from canopy to fruit as determined by avocado tree physiology. 2007 Production Research Report - California Avocado Commission, 17. Hofshi R. (1998) Dreaming in reality. California Avocado Society 1998 Yearbook 82, 137-54. Hogan L. & Thorpe S. (2009) Issues in food miles and carbon labelling. In: ABARE research report p. 48. ABARE, Canberra. Howden M., Newett S. & Deuter P. (2006) Climate change-risks and opportunities for the avocado industry. In: New Zealand and Australia Avocado Grower’s Conference pp. 119, Tauranga.


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Iglesias I., Salvia J., Torguet L. & Cabus C. (2002) Orchard cooling with overtree microsprinkler irrigation to improve fruit colour and quality of 'Topred Delicious' apples. Scientia Horticulturae 93, 39-51. Iglesias I., Salvia J., Torguet L. & Montserrat R. (2005) The evaporative cooling effects of overtree microsprinkler irrigation on 'Mondial Gala' apples. Scientia Horticulturae 103, 267-87. IPCC. (2007) Climate change 2007 synthesis report summary for policymakers. Intergovernmental Panel on Climate Change. Jablonski L. M., Wang X. Z. & Curtis P. S. (2002) Plant reproduction under elevated CO2 conditions: a meta-analysis of reports on 79 crop and wild species. New Phytologist 156, 9-26. Jiang T., Hanslow K. & Pearce D. (2009) On farm impacts of an Australian ETS: An Ecconomic Analysis. Rural Industries Research and Development Corporation (RIRDC), Canberra. Keogh M. & Thompson A. (2008) Preliminary modelling of the farm-level impacts of the Australian greenhouse emissions trading scheme. p. 28. Australian Farm Institute, Sydney. Kimball B. A., Idso S. B., Johnson S. & Rillig M. C. (2007) Seventeen years of carbon dioxide enrichment of sour orange trees: final results. Global Change Biology 13, 217183. Labanauskas C. K., Stolzy L. & Zentmyer G. A. (1978) Rootstock, soil oxygen, and soil moisture effects on growth and concentration of nutrients in avocado plants. California Avocado Society Yearbook 62, 118-25. Lahav E. & Trochoulias T. (1982) The effect of temperature on growth and dry-matter production of avocado plants. Aust. J. Agric. Res. 33, 549-58. Lahav E. & Whiley A. W. (2002) Irrigation and mineral nutrition. In: The Avocado: botany, production and uses (eds A. W. Whiley, B. Schaffer and B. N. Wolstenholme). CABI publishing, Oxon. Lobell D. B., Cahill K. N. & Field C. B. (2007) Historical effects of temperature and precipitation on California crop yields. Clim. Change 81, 187-203. Lomas J. (1988) An agrometeorological model for assessing the effect of heat stress during the flowering and early fruit set on Avocado yields. J. Amer. Soc. Hort. Sci. 113, 172-6. Long S. P., Ainsworth E. A., Leakey A. D. B., Nosberger J. & Ort D. R. (2006) Food for thought: lower-than-expected crop yield stimulation with rising CO2 concentrations. Science 312, 1918.


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Loupassaki M. & Vasilakakis M. (1995) The effect of temperature and relative humidity on the in vitro germination of the pollen of avocado In: The World Avocado Congress III pp. 42-5, Israel. Maceda A., Hohmann C. L. & dos Santos H. R. (2003) Temperature effects on Trichogramma pretiosum Riley and Trichogrammatoidea annulata de Santis. Brazilian Archives of Biology and Technology 46, 27-32. McCarthy A. (2009) Harvesting Hass during high temperature. In: 4th Australian and New Zealand Avocado Growers Conference (ANZAGC09) Cairns, Australia. Meyer J., Arpaia M., Yates M., Takele E., Bender G., Witney G., Embleton T., Strohman R. & Stottlemyer D. (1992) Irrigation management and fertilisation management avocados. In: 1992 Summary of Avocado Research (ed A. R. A. Committee) pp. 6-10. University of California, Riverside. Mickelbart M., Bender G., Witney G., Adams C. & Arpaia M. (2007) Effects of clonal rootstocks on 'Hass' avocado yield components, alternate bearing, and nutrition. Journal of Horticultural Science & Biotechnology 82, 460-6. Moretti C., Mattos L., Calbo A. & Sargent S. (2009) Climate changes and potential impacts on postharvest quality of fruit and vegetable crops: A review. Food Research International. Nava D. E., Haddad M. D. & Parra J. R. P. (2005) Temperature requirements, estimate of the generations number of Stenoma catenifer and verification of the model in the field. Pesquisa Agropecuaria Brasileira 40, 961-7. Nesbitt H. J., Malajczuk N. & Glenn A. R. (1979) Effect of soil moisture and temperature on the survival of phytophthora cinnamomi rands in soil. Soil Biology and Biochemistry 11, 137-40. Neuhaus A., Turner D. W., Colmer T. D. & Blight A. (2009) Drying half of the root-zone from mid fruit growth to maturity in 'Hass' avocado (Persea americana Mill.) trees for one season reduced fruit production in two years. Scientia Horticulturae 120, 437-42. Newett S. (1999) Current status of canopy management in Australia. Session 3: Canopy management. In: Avocado Brainstorming (eds M. Arpaia and R. Hofshi) pp. 56-9. Hofshi Foundation, University of California, Riverside. Nielson L. (2010) Emissions control: your policy choices. In: Parliamentary Library Background Note p. 24. Parliamentary Library, Parliament of Australia, Canberra. Parchomchuk P. & Meheriuk M. (1996) Orchard cooling with pulsed overtree irrigation to prevent solar injury and improve fruit quality of 'Jonagold' apples. Hortscience 31, 802-4. Pegg K. G., Coates L., Korsten L. & Harding R. M. (2002) Foliar, Fruit and Soilborne Diseases. In: The Avocado: Botany, Production and Uses (eds A.W.Whiley, B. Schaffer and B. N. Wolstenholme) pp. 299-338. CABI Publishing, Oxon.


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Perez-Jimenez R. M. (2008) Significant avocado diseases caused by fungi and oomycetes. The European Journal of Plant Science and Biotechnology 2 (1), 1-24. Peterson P. A. (1955) Avocado flower pollination and fruit set. California Avocado Society 1955 Yearbook 39, 163-9. Phillips D. & Weste G. (1985) Growth rates of four Australian isolates of Phytophthora cinnamomi in relation to temperature. Transactions of the British Mycological Society 84, 183-5. Planet Ark. (9 June 2010) ALDI first to join Carbon Reduction Label Program in Australia. In: Media release. Planet Ark. (27 October 2010) Australians can now start to track carbon footprints of products. In: Media Release. Planet Ark. Planet Ark. (2009) Carbon Reduction Label launches in Australia Ploetz R. (2009) Status, impact and management of the major diseases of avocado. In: 4th Australian and New Zealand Avocado Growers Conference (ANZAGC09), Cairns, Australia. Pratissoli D., Zanuncio J. C., Vianna U. R., Andrade J. S., Pinon T. B. M. & Andrade G. S. (2005) Thermal requirements of Trichogramma pretiosum and T. acacioi (Hym.: Trichogrammatidae), parasitoids of the avocado defoliator Nipteria panacea (Lep.: Geometridae), in eggs of two alternative hosts. Brazilian Archives of Biology and Technology 48, 523-9. Ro H. M., Kim P. G., Lee I. B., Yiem M. S. & Woo S. Y. (2001) Photosynthetic characteristics and growth responses of dwarf apple (Malus domestica Borkh. cv. Fuji) saplings after 3 years of exposure to elevated atmospheric carbon dioxide concentration and temperature. Trees-Structure and Function 15, 195-203. Sanderman J., Farquharson R. & Baldock J. (2010) Soil carbon sequestration potential: A review for Australian agriculture. p. 89. CSIRO Land and Water. Schaffer B. & Whiley A. W. (2002) Environmental physiology. In: The Avocado: Botany, Production and Uses (eds A. W. Whiley, B. Schaffer and B. N. Wolstenholme) pp. 13560. CABI Publishing, Oxon. Schaffer B. & Whiley A. W. (2003) Environmental regulation of photosynthesis in avocado trees - a mini review. In: World Avocado Congress V pp. 335-42, Mexico. Schaffer B., Whiley A. W. & Searle C. (1999) Atmospheric CO2 enrichment, root restriction, photosynthesis, and dry-matter partitioning in subtropical and tropical fruits. Hortscience 34, 1033-7. Schroeder C. A. & Kay E. (1961) Temperature conditions and tolerance of avoado fruit tissue. California Avocado Society Yearbook 45, 87-92.


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Sedgley M. & Annells C. M. (1981) Flowering and fruit-set response to temperature in the avocado cultivar Hass. Scientia Horticulturae 14, 27-33. Sedgley M. & Grant W. J. R. (1982/1983) Effect of low temperatures during flowering om floral cycle and pollen tube growth in nine avocado cultivars. Scientia Horticulturae 18, 207-13. Sedgley M., Scholefield P. & Alexander D. M. (1985) Inhibition of flowering of Mexicanand Guatemalan- type avocados under tropical conditions. Scientia Horticulturae 25, 2130. Shepherd C. J. & Pratt B. H. (1974) Temperature-growth relations and genetic diversity of A2 mating-type isolates of Phytophthora cinnamomi in Australia. Australian Journal of Botany 22, 231-49. Tulloh C., Ahammad H., Mi R. & Ford M. (2009) Effects of the Carbon Pollution Reduction Scheme on the economic value of farm production. In: Issues insights p. 18. Australian Bureau of Agricultural Research and Economics (ABARE), Canberra. Turner D., Neuhaus A., Colmer T., Blight A. & Whiley A. W. (2001) Turning water into oil -physiology and efficiency. In: Australian and New Zealand Avocado Growers Conference 2001, Bundaberg. Vock N., Newett S., Whiley A. W., Dirou J., Hofman P., Ireland G., Kernot I., Ledger S., McCarthy A., Miller J., Pinese B., Pegg K. G., Searle C. & Waite G. (2001) Agrilink Horticulture Series. In: Avocado Information Kit (ed N. Vock). The State of Queensland Department of Primary Industries, Brisbane. Vuthapanich S., Hofman P., Whiley A. W., Klieber A. & Simons D. (1995) Effects of irrigation and foliar Cultar on fruit yield and quality of 'Hass' avocado fruit. In: World Avocado Congress 3 pp. 311-5, Israel. Waite G. K. & Martinez-Barrera R. (2002) Insect and mite pests. In: The Avocado: Botany, Production and Uses (eds A. W. Whiley, B. Schaffer and B. N. Wolstenholme). CABI Publishing, Oxon. Webb L. & Whetton P. H. (2010) Horticulture. In: Adapting agriculture to climate change preparing Australian agriculture, forestry and fisheries for the future (eds C. Stokes and M. Howden). CSIRO Publishing, Collingwood VIC. Whiley A. (1999) Investigation of potential productivity benefits to tropical and subtropical tree fruit and nut crops from elevated CO2 levels: report for RIRDC project DAQ-156A. Whiley A. W., Schaffer B. & Wolstenholme B. N. (2002) The Avocado: Botany, Production and Uses. CABI Publishing, Oxon. Witjaksono, Schaffer B. A., Colls A. M., Litz R. E. & Moon P. A. (1999) Avocado shoot culture, plantlet development and net CO2 assimilation in an ambient and CO2 enhanced environment. In Vitro Cell. Dev. Biol.-Plant 35, 238-44.


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Climate change factsheets for the Australian avocado industry AV09003 David Putland Jane Muller Growcom

December 2010 Growcom 68 Anderson St Fortitude Valley PO Box 202 Fortitude Valley QLD 4006 Tel: 07 3620 3844 | Fax: 07 3620 3880 www.growcom.com.au

AV09003. Climate change factsheets for the Australian avocado industry. This document contains proposed content for two climate change factsheets for the avocado industry. These factsheets were developed for project AV09003: Climate change and climate policies for the Australia avocado industry. These factsheet are currently labelled "draft" as we expect to make further refinements in response to feedback from Avocados Australia and to suit the particular layout requirements of the final documents.

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Factsheet #1: Carbon footprinting for avocado growers. A carbon footprint is a measure of the greenhouse gas emissions caused by a certain product or activity. While the term is commonly used, it is loosely defined and can mean different things to different people. This factsheet will clarify the role of carbon footprinting for avocado growers, and show you how you can easily calculate the carbon footprint of your farm.

What is included in a carbon footprint? While “carbon footprint” is the accepted term in widespread use, it is important to remember that it includes a number of other greenhouse gases in addition to carbon dioxide (CO2). There are actually six main gases that contribute to the greenhouse effect, but they vary in the strength of their effects (called “global warming potential”). For example, nitrous oxide (a by-product of fertiliser use) has about 300 times the warming potential of carbon dioxide. Because of this variation among the different gases, the amounts of each gas must be weighted according to their warming potential and then combined into a single measurement. The unit used to measure a carbon footprint is tonnes of carbon dioxide equivalent (or t CO2-e). Table 1: A summary of the major agricultural greenhouse gases. Greenhouse gas Carbon dioxide (CO2) Nitrous oxide (N2O) Methane (CH4)

Global warming potential 1 310 21

Source Mainly from fossil fuel use Excess fertiliser Mainly livestock, waste and waterlogged soils.

The rules for calculating a carbon footprint are governed by the Australian National Carbon Offset Standard (NCOS). Under this standard, there are different rules for calculating the footprint for a product or for a business. The recommended rules for calculating the footprint of a product (for example, a tray of avocados) are complicated and probably require the assistance of a specialist consultant. Fortunately, the rules for calculating the footprint of a business (such as an avocado orchard and/or packing enterprise) are far more straightforward. In this case, the calculations need to include: • •

Direct emissions that occur on-site (also called “scope 1” emissions) such as burning fuel in a tractor or the emissions from excess fertiliser. Indirect emissions (“scope 2”) that occur elsewhere but are still associated with the business (e.g. the emissions released by generating the electricity that is consumed on the farm).

The National Greenhouse Accounts factors calculated by the Department of Climate Change and Energy Efficiency provide simple formulae to convert energy consumed (eg. kWh of electricity or litres of diesel) into a quantity of emissions released.

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Measuring the carbon footprint of your farm? You can calculate the carbon footprint of your farm quite easily provided you have access to the required information and data. HortCarbonInfo is a simple carbon footprint calculator created specifically for horticulture by Peter Deuter (Agri-Science Queensland). It is an Excel™ spreadsheet into which you can enter your information. For a complete footprint, you will need data over a 12 month period that includes: • • • • • • •

•

Hectares of crop/orchard. Kilowatt-hours of electricity used for all farming operations. Litres of petrol, diesel and LPG used for any stationary operations such as pumps or generators. Litres of petrol, diesel and LPG used for vehicles on-farm such as tractors, utes or cherry pickers. Types and tonnes of fertilisers applied for the production of the crop and the nitrogen content of these fertilisers. Types and tonnes of animal manures applied for the production of the crop and the nitrogen content of these manures. Tonnes of waste disposed either on-farm or to municipal waste divided in the categories of paper and cardboard, green waste, concrete/metal/plastic/ glass and co-mingled. Kilograms of hydroflourocarbons used to fully charge any refrigeration systems used on farm.

This tool performs all of the necessary conversions and calculations for you, and then produces your farm’s total carbon footprint. You can use HortCarbonInfo to identify the areas where you can improve your footprint and compare results across years. You can get a copy of HortCarbonInfo from here:

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Figure 1. The data input page of the HortCarbonInfo carbon footprint calculator.

Reducing your carbon footprint. The horticulture industry already has very low emissions in comparison to other agricultural sectors. However, there is scope to further reduce these emissions and lessen the impact of horticulture on future climate change. Reducing your carbon footprint is directly linked to other beneficial farm management practices that improve soil health and increase production efficiency. On-farm nitrous oxide (N2O) emissions are a major problem for horticulture. The greatest emissions of N2O result from a combination of: • Excess nitrates in the soil from the application of nitrogen fertilisers. • Anaerobic conditions, such as waterlogged or compacted soils. In short, N2O emissions represent wasted fertiliser and wasted money. Emissions of N2O can be reduced through: • Improved fertiliser use efficiency. • Reduced water logging. • Reduced compaction (eg. by reducing farm traffic).

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• • •

Maintaining continuous plant cover. Building soil organic matter. Avoiding burning of crop waste.

Many of these management practices for reducing emissions have additional benefits in other areas, such as increasing yields, improving water use efficiency and reducing hazardous runoff. Many of these practices are already widely used in the industry because of these additional benefits, but the financial investment required limits the rate of adoption in the absence of suitable incentives. Indirect emissions resulting from energy use are often the major contributor to the carbon footprint of an avocado farm. You can reduce indirect emissions improving energy and fuel efficiency use, not just within your own business, but your suppliers and contractors as well. Some typical steps include: • • • • • •

Reducing electricity consumption through more efficient refrigeration, variable speed pumps etc. Reducing liquid fuel use with more efficient machinery and pumps, reduced on-farm traffic, and streamlined workflows. Reducing waste (recycling). Adding renewable energy sources such as on-farm generation of electricity using solar, small scale wind generators and biofuels. Selecting suppliers based on their carbon footprints. More efficient distribution and product handling.

It is not necessary to race out and buy the latest pump technology tomorrow, but energy efficiency should be a primary consideration in future equipment purchases or planning activities. Many of the steps that can be used to reduce a farm’s footprint will also result in reduced input costs. A small carbon footprint can be used as an indicator of production efficiency. Finally, consumer preferences are likely to drive demand for more environmentally-friendly products. A smaller carbon footprint may provide a distinct marketing advantage over other agricultural sectors and imported produce.

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Factsheet #2: Adapting to a changing climate. This factsheet outlines some of the potential impacts of climate change and how avocado growers can adapt to the changing conditions. The most recent report from the Intergovernmental Panel on Climate Change (IPCC - an international panel that assesses the scientific, technical and socio-economic information relevant to climate change) contained modelling results suggesting that we can expect the average global temperature to rise between 1 and 6°C by the end of this century. Of course, the temperature change will not be uniform and some areas will experience greater increases than others. In fact, Australian annual average temperatures have already increased by about 0.8°C since 1910. In addition to simple temperature rises, there have been other observed changes such as decreases in snow cover, glacier melt, reductions in sea ice, and clear changes in the timing of flowering and fruiting in plants.

Potential impacts on avocado production. As growers, you are already familiar with the challenges posed by a highly variable climate. Climate variability will continue as always, but against a background of gradual climate change, the hot and dry seasons are likely to become more common and more extreme in the future. Over the next decade or two, the changes will be relatively small and you will be able to employ the same strategies you use now to deal with current variability. However, the cumulative effect over time of these gradual changes may eventually stretch or exceed current approaches. Although there is no need to panic about the impacts of a changing climate, it is certainly worth planning ahead to consider a range of contingency plans that could be employed if or when the need arises. A recent analysis of the projected climate changes across the main Australian avocado growing regions indicates that the impacts will vary among production regions. For example, Figure 1 outlines projected changes over the next 70 years in a critical temperature envelope for the Hass variety. While these maps provide a quick estimate of potential climate risk across Australia, the results should be viewed with a degree of caution. There is some uncertainty in the spatial data and underlying climate models. Other important factors in addition to climate may have important effects, and the process ignores climate adaptation measures that may already be in place or that may be applied in the future (eg. different varieties; see Table 1 for more information). For example, while these analyses suggest that Queensland growing regions may face challenging conditions by about 2050, the widespread use of the Shepard variety which is suited to hotter and drier conditions may prolong successful production in those regions.

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current

2050

2020

2080

Figure 1. Projected changes in an estimated critical temperature envelope across Australia. Dark green indicates those areas that meet all temperature criteria.

A number of general trends emerge from climate models. The increase in average temperatures will occur mostly through more hot days and fewer cool nights. Rainfall events are likely to be heavier but concentrated into a shorter wet season. There are also likely to be more frequent and extreme weather events (cyclones, droughts etc.).

Adapting to a changing climate. One thing that is clear from these recent analyses is that the Australian avocado industry is not facing imminent ruin. The changes are likely to manifest over several decades and there are several management responses that can be used to mitigate any negative effects. Table 1 provides a quick summary of some of these on-farm management options. In addition, the development and use of new rootstocks and varieties that are better adapted to particular conditions, and with better yield and quality, has excellent potential to combat projected climate impacts.

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Table 1. A summary of potential management responses to projected climatic changes. Projected climate changes Overall warming

Management responses / adaptation strategies • • • •

Reduced diurnal temperature range

• • • •

Higher night temperatures Higher summer day maximum temperatures

• • • •

• • • • • • • Higher day and night temperatures in autumn and winter and fewer frosts

• • •

Increased chance of heat stress conditions in spring

•

Increased incidence of excessively wet periods, more intense rainfall events

•

AV09003 factsheets

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Earlier harvest Apply practices to manage heat and sunburn if harvesting in high temperatures Adjust marketing plans if harvest times shift significantly Proactive pest management strategies using an Integrated Pest Management approach Consider shift in production location Improve chances of pollination by ensuring adequate bee activity in an orchard at flowering Plant pollinator varieties in blocks consisting of single varieties Maximise fruit retention through a strong focus on irrigation, nutrition, pest and mulch management Increase use of plant growth regulators to improve fruit size Develop marketing strategies for small / lunchbox-sized Hass Increase emphasis on preventative disease control strategies Better irrigation management through more intensive moisture monitoring, more responsive scheduling, and the use of different types of irrigation (e.g. pulse irrigation and irrigation directed at cooling the canopy with sprinklers) Increase water supply and security (e.g. expansion of on-farm water storage capacity) Mulch to help maintain appropriate soil temperature and conserve moisture More effective control of Phythophthora cinnamomi Apply sunburn protection products to fruit Selectively harvest exposed fruit early in season Where possible adjust timing of pruning to minimise exposure of fruit to sunburn Increase monitoring for fruit spotting bug, implement integrated and new control measures Shorten the harvest period More frequent use of plant growth regulators to improve the small fruit size Where flowering is sparse: • Ensure adequate bee activity in orchard at flowering • Plant pollinator varieties in blocks consisting of single varieties • Maximise fruit retention through strong focus on tree health, irrigation, nutrition, pest and mulch management A higher level of irrigation management through more intensive moisture monitoring, more responsive scheduling, and the use of different types of irrigation (e.g. pulse irrigation and irrigation directed at cooling the canopy with sprinklers) When selecting new orchard locations, choose sites that have a greater depth of well drained soil and/or sites where superior drainage can be achieved (e.g. through higher row mounding, and surface and sub-surface drainage) Improve existing drainage in the orchard Increase use of recommended mulching practices

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• • • • • Increased incidence of storm and cyclone events

• • •

Increased incidence of drought conditions and drier spring weather

• • • • • •

Increased carbon dioxide levels in the atmosphere

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Monitor soil moisture more closely and improve irrigation and nutrient management, compensating where necessary for nutrients leached by excessive rainfall Use of Phythophthora resistant / tolerant rootstocks Increase anthracnose control measures Always apply recommended postharvest fungicide to fruit Use rootstocks better adapted to wet conditions Increase on-farm water storage capacity and maximise harvest of runoff water May require re-location Well-designed windbreaks using carefully selected species or artificial materials Adopt canopy management strategies that favour a smaller, more robust tree Be able to supply more irrigation when required Improve micro-management of water with better moisture monitoring and irrigation scheduling Install more effective and water efficient irrigation systems Consider ways to increase water supply and security Use mulch to help maintain appropriate soil temperature and conserve moisture Aim for smaller trees at higher densities as these are more efficient at using water (per tonne of fruit produced) Closer monitoring of plant nutrient levels and more responsive remedial action to maintain optimum levels in tree Select rootstocks with higher levels of nutrient uptake More frequent use of plant growth regulators to improve small fruit size expected with higher levels of fruitset Conduct research to investigate the effect of higher carbon dioxide levels in combination with higher temperatures

Adapting to climate policies. Although climate policies (eg. emissions trading or a carbon tax) in Australia are still in the early stages of development, any new policy is likely to result in higher farm input costs (eg. fuel, electricity and fertiliser). These costs can be minimised by focussing attention on energy and production efficiency, which has the added benefit of reducing your farm’s carbon footprint.

What can you do? The most important thing is to be aware of the risks and to start thinking about how they can be avoided if necessary. For example, are more tolerant varieties available and is it feasible to switch? Can you increase the security of irrigation water supply, either by increasing efficiency or storage capacity? Is there a cost-effective way to keep your crops cool to avoid damage from higher temperatures? In the worst case scenario, your current crops may no longer be viable or profitable; are there any other more adaptable or drought-tolerant crops that may be suitable for your area and form the basis of a profitable business?

AV09003 factsheets

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David Putland Jane Muller Growcom 68 Anderson St PO Box 202 Fortitude Valley QLD 4006 (07) 3620 3844 [email protected] [email protected]

AV09003 factsheets

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Grant Receipient:

Activity Project Title: Agreement Number:

Growcom Australia Climate change and climate policy implications for the Australian avocado industry AV09003

Reporting Date Range

01/12/2009-31/12/2010

Funds Managed by HAL 101

$

30,172.20


$

10,057.40


$

10,057.40

Income

$

50,287.00

Salary Climate Change Office

$

69,750.00

Communication

$

290.70

Travel and Accommodation

$

761.82

Project Management

$

7,417.33

Total Expenditure

$

78,219.85

Expenditure

-$27,932.85

Funds still to received on approval of MS190