The Regional Impacts of Climate Change

Other reports in this collection Adaptation and Vulnerability

Agriculture is an intrinsically adaptive activity. Farming in the region is highly decentralized, technologically well-supported, and market-responsive and routinely deals with variability on a variety of time scales, arising from climatic, biological, and market factors. Operational decisions on the variety of crop and animal options are made annually or more frequently; structural investment decisions on the farm or orchard, and at processing plants, have a currency of a decade or so. Although adjusting production systems to changing climate will not be without cost and will require systematic awareness-raising and information dissemination (Stafford Smith et al., 1994), it is very likely to be a smaller and slower influence than changes arising from markets, prices, and technology. Furthermore, gains in production in some areas may offset or even exceed costs.

Adaptation options include plant breeding and cultivar choice, adjustment of planting times to realign thermal and vernalization requirements, changes in crop sequences, improved soil management, diversification of crops, adoption of sustainable farming methods, monitoring and prediction of seasonal climate and associated crop and pasture/livestock modeling, and regional monitoring and management of drought (Gifford et al., 1996b). Adaptation strategies will need to go hand in hand with mitigation strategies to reduce farm system emissions of greenhouse gases where there may be significant opportunities to act as a carbon sink (Ash et al., 1996) or reduce methane emissions (Howden et al., 1994).

In rangeland agriculture, more flexible management responses to enable adjustment to fluctuating forage supplies would be required if there were changes in the frequency or intensity of extreme events (McKeon et al., 1993). The resulting land-use change may have considerable regional socioeconomic impacts-as well as raising issues relating to sustainable use of land and water resources. Approaches to soil erosion control, pest animal management, weed control, and tree-clearing may have to be adjusted as climate changes. Seasonal to interannual climate prediction, particularly of rainfall in the ENSO-affected agricultural areas, is an adaptation option that offers increasing potential to manage climate variability.

Existing trends of diversification and specialization also provide a basis for the development of adaptation strategies (Stafford Smith et al., 1994). Many potential adaptation options already will exist in particular farming systems or particular localities, but their widespread use may require further research and coordination at different scales, from land managers to governments (McKeon et al., 1993). Adaptations involving changes to crop types, farming systems, and adjacent ecosystems may change vulnerability to biological risks; such risks also may be minimized by the introduction of less vulnerable species or increased diversification in farming systems.

The existing diversity of uses of Aboriginal land will provide resilience in coping with change, though some traditional management approaches such as the use of fire and harvesting of native foods may need to be modified. There will be a need to develop awareness of climate change among Aboriginal managers, and to learn from the traditional Aboriginal management, which has survived past climatic changes (Stafford Smith et al., 1994).

Recent policy changes by the region's governments have shifted a greater part of the responsibility for agricultural risk management to farmers and the private sector. This shift was effected partly to cut the cost and overheads of government payouts to farming communities during droughts and other weather-related disasters and partly to promote more economically and environmentally rational decisions in land use and farm investment; the goal was to encourage decisions that properly account for the long-run risks involved. Although this approach is sound in principle and should improve outcomes over the medium term, there probably will be many individual farmers who will be unable to appraise, cost, or insure against a widespread very extreme event, an increased frequency of extreme events, or the generally uncertain effects of climate change. These risks inevitably become shared by the whole community and so remain a responsibility for community cooperation and government leadership. Few farmers in the region make use of commercial crop insurance.

The capacity of the region's agricultural industry to adapt to climate change will depend on the magnitude of change and hence the time frame. Over the next few decades-when the warming will be relatively small and the rainfall perhaps little changed-adaptation techniques are likely to be sufficient to cope without great consequences, and vulnerability will be small. However, as the time horizon extends and the climate changes become larger, there is likely to be a trend toward reduced production and increasing aridity in many areas (mainly in Australia). The greatest vulnerability appears to lie in the context of this long-term outlook, in the uncertainty of possible changes in rainfall associated with synoptic weather patterns and the ENSO phenomenon, and in possible external market responses and biological risks.

The forestry industry has some degree of vulnerability to climate change but may also gain from productivity increases. Greater attention to forest management-particularly with respect to seedling establishment, soils, fire risk, and disease-may be a required adaptation. In exotic production forestry, the multidecadal crop cycle is still sufficiently short to allow some adaptation through choice of species and of areas for planting.

The principal adaptation option for all categories of fisheries is integrated management through international and national mechanisms as appropriate and including consideration of habitat and all life-cycle stages. The greatest vulnerability is expected for freshwater fisheries generally-owing to direct temperature and hydrological effects and limited adaptation possibilities in the confines of rivers and lakes-and for fisheries dependent on estuaries and mangroves that may become subject to sea-level rise, flooding, and pollution by organisms, chemicals, and sediment from runoff (IPCC 1996, WG II, Chapter 16).

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