INCREASED AUSTRALIAN WHEAT YIELD DUE TO RECENT CLIMATE TRENDS

The possibility that future climate change may affect agriculture has attracted considerable attention(1,2). As a step towards evaluating su ch influences, the effect of climate trends over the past few decades( 3) needs to be assessed. Here I estimate the contribution of climate t rends in Australia(4,5) to the substantial increase in Australian whea t yields since 1952. Non-climatic influences-such as new cultivars and changes in crop management practices-are removed by detrending the wh eat yield and climate variables and using the residuals to calculate q uantitative relationships between variations in climate and yield. Cli mate trends appear to be responsible for 30-50% of the observed increa se in wheat yields, with increases in minimum temperatures being the d ominant influence. This approach should be applicable in other regions for which sufficient data exist.