Agriculture and Forestry

A significant proportion of exports from Australia are agricultural and forestry products- production of which is sensitive to any changes in climate, water availability, carbon dioxide fertilisation, and pests and diseases. Returns from these commodities could be affected by a projected increase in agricultural production in mid- to high-latitude Northern Hemisphere countries and resulting impacts on commodity prices and world trade. Climate change will be only one factor affecting Australian agriculture, but it may exacerbate an already difficult situation, particularly in regard to the availability of water for irrigation.

Agricultural activities are particularly vulnerable to projected regional reductions in rainfall in the south-west and possibly other parts of southern Australia, and are especially threatened by general warming that will increase potential evaporation and water demand. Drought frequency and severity, and consequent stresses on agriculture, are likely to increase in many agricultural regions of Australia. This would be exacerbated by any tendency toward a more El Niño-like average state. Enhanced plant growth and water-use efficiency resulting from carbon dioxide increases may provide initial benefits that offset any negative impacts from climate change, although the balance is expected to become negative with warmings in excess of 2-4 °C and associated rainfall decreases. Thus by the mid to late 21st century net effects on agriculture are likely to be negative.