A new approach to detection of anthropogenic temperature changes in the Australian region

A new method has been applied for detecting a human influence on regional temperature changes in Australia over the last 50 years, including the whole of Australia, the southern half of Australia and the southeastern sector of Australia. There was a strong relationship between interannual variations of rainfall and temperature in different regions in Australia. The rainfall-related component of the temperature variations was removed using linear regression and the residual temperature variations were much smaller for maximum and mean temperature, and diurnal temperature range. Model simulations of regional temperature and rainfall variations agreed reasonably well with observations. Trends in the residual variations of maximum, mean and minimum temperature over the last 50 years could not be explained by natural climate variations in all the regions considered and were consistent with the response to increasing greenhouse gases and sulphate aerosols in the climate models. This new approach has been able to enhance the signal-to-noise ratio for anthropogenic temperature change signals in the Australian region and to show that there is a clear anthropogenic warming signal in observed regional temperature trends, even for regions as small as the southeastern sector of Australia.