Assessing dangerous climate change impacts on Australia�s wheat industry

Atmospheric carbon dioxide (CO2) concentrations and global and regional climates are already changing as a result of human activities. More change seems likely. Historical climate variations, particularly in rainfall, have had significant impacts on the Australian cropping industries and consequently we would anticipate additional impacts from future climate change. However, the magnitude of these changes is highly uncertain at regional levels especially for rainfall. To deal with this uncertainty a systematic assessment approach is described here that separates the effects of changed temperatures, rainfall and CO2 concentration on regional and national wheat yields, including the effects of management adaptations in response to the above changes. This allows addressing questions such as ‘Are there beneficial effects of moderate warming?’ ‘If so, at what point does further warming become negative?’ and ‘What is the benefit of management adaptation to climate changes?’ Furthermore, the approach allows recombination of the components in a risk assessment approach to investigate questions such as ‘What level of CO2 increase is required to offset deleterious changes in rainfall and temperature ?’ or ‘What is the probability of reductions in the value of the wheat industry ?’