CLIMATE CHANGE AND THE AUSTRALIAN HORTICULTURE INDUSTRY

(PREPARED BY DAFF/HAL THROUGH THE CCRSPI PROGRAM). 

Discussions about climate change can be hard to understand and focused on scenarios far into the future. Complex economic models often did not explain actions in terms of what can be done now, through existing business operations and strategies, to help business reduce greenhouse gas emissions (mitigation) and prepare for a future climate conditions (adaptation).  Horticulture Australia Ltd (HAL) and the Climate Change Research Strategy for Primary Industries (CCRSPI) have produced information so that growers will have access to that information regarding:

• Predicted climate change impacts on horticulture.
• Research underway to assist growers to respond to climate change.
• Practical measures to mitigate and adapt to the challenges and opportunities presented by climate change.
• Glossary of commonly used climate change terms.

Climate Change Impacts and Opportunities:

Horticulture is the third largest agricultural industry in Australia with a gross value of production (GVP) of $8.6 billion.  The sector employs one in four agricultural workers and delivers products and services that enhances the lifestyle and quality of life in homes and cities, and play a vital role in delivering national food security.  Australia’s increasingly variable climate poses challenges for horticulture, given the sector’s dependence on natural resources especially water for irrigation.  This makes horticulture inherently vulnerable to the impacts of both short term climate variability and long-term climate change.  In comparison to other agricultural sectors, horticulture has a small environmental impact relating to climate change.  This low level of emissions is due in part to the types of crops grown and the fact that minimal tillage is involved helps to build up and contained carbon in the soil.  While agriculture emissions amount to some 16% of all national industry emissions, “Horticulture” comprises just 1% of this total.

Despite these good credentials the industry is still vulnerable to predict changes to rainfall and temperature that will impact on, plant growth, pest and disease risk, product quality and industry location.  The extent these physical impacts affect horticulture products, and businesses will be further shaped by the:

• Growing global demand for food.
• The impacts of climate change policy.
• Increasing demands for productivity growth.
• Increasing competition natural resources.
• Requirements of ever more efficient and sustainable production practices.

Temperature and rain fall changes present the greatest biophysical impacts on the horticulture sector’s ability to remain profitable and competitive.

By 2030 under the medium climate change omission scenario is, the annual temperature across Australia is expected to have warmed up by about 1.0° C relative to 1990.  Inland areas are likely to experience strong the warming recycled of up to 1.8° C, the coastal areas warming a little less.  Climate modelling experts predict there will be significant variations from region to region, with night-time temperatures increasing faster than daytime temperatures.  This temperature increase is expected to grow further (more than double) by 2070.

Changes in rainfall are expected to vary widely across regions and seasons. By 2030 rainfall is projected to increase by 2-5% across Australia, except in northern Australia where little rain fall change is projected.  Importantly, run-off will also substantially declined, resulting in significant negative impact for water quality and quantity.  By 2070, annual rainfall is estimated to have decreased by about 7.5% across Australia, with the exceptions of the far north where there will be little change in South Western Australia with increases of up to 40% are expected.  Due to the projected changes in rainfall, soil moisture is likely to decline over much of southern Australia.

What does this mean to our horticulture businesses?

As the following snapshots indicate, the combined impact of the predicted changes to rainfall and temperature will affect horticulture commodities and regions in a number of ways.

1. Changes in enterprise structure and location – changes to growing conditions will impact on the suitability of regions and different crops.
2. Changes to crop selection/mix– changes to growing conditions will impact on the suitability and adaptability of current cultivars, including the need to match crop selection with optimum growing times.
3. Changes to irrigation– increased irrigation demand and changed the reliability of irrigation schemes and water availability will impact on growers irrigation scheduling.
4. Impacts on soil management– more intense 10 rainfall events (coupled with warmer temperatures) may result in the increased risk of spread and proliferation of soil borne diseases.
5. Impact on current integrated pest– there is the potential for changes in the distribution of existing pests, diseases and weeds, and an increased threat of incursions into new crops.
6. Increased incidence of physiological disorders and associated impacts of product quality and yields – tip burn, blossom end rot, hail damage and soil erosion could all increase with higher incidences and severity of extreme events.
7. Increased public and political pressure on the use of resources –increased competition, reduced reliability and rising costs will all increase pressures to improve on-farm efficient use of natural resources.
8. Increased economic impacts – there will be in impact of the Australian government’s carbon pollution reduction scheme at the sector is exposed to change compliance costs, input costs and flow on costs from the supply chain that supports it; example, through new requirement product labelling and other regular Tory requirements (both domestically and overseas).

A case study of the vegetable growing industry in the Central Riverina area in 2008 demonstrated both negative and positive impacts of climate change on production.

Negative impacts:

• Higher cost of irrigation under hotter conditions.
• Impact on quality two effects of sunburn and frost.

Positive benefits:

• Earlier maturing crop resulting in a 10 to 15 day jump on competitors into the market.

A summary of climate change impacts on horticulture:

1. Horticulture industry has been, and will continue to be, vulnerable to impacts of climate change and climate variability.
2. Impacts vary between horticulture and other agricultural industries as well as within horticultural communities and their growingThey can even be variability in impacts within a business.  There is a need of further work to be undertaken to better understand and communicate the impacts within the industry.
3. Aside from the physical impacts of climate change, the main challenges of the horticulture sector of the need to respond to both changes in consumer preferences and the impacts of climate change policy decisions (including the introduction of the CPRS).  Policy changes would include new compliance costs and increased input costs without growers necessarily being able to pass on the costs toImproved understanding of these impacts is required to inform research, development and extension (RD&E) responses.
4. The ongoing drought in many key horticultural regions has had an immediate significant impact and will reduce the long term resilience of the horticultureClimate change will continue to impact on water resources into the future.
5. There are still potential opportunities for horticulture in a changing climate, including the potential for an increase in productive capacity due to increased carbon dioxide levels.
6. However the extent and sustainability of these potential benefits are not well understood.