Temperatures in Australia could rise by 4.5oC by 2090, according to a keynote address research fellow Steven Crimp has delivered at the University of Western Australia’s Institute of Agriculture Industry Forum 2020. Long-term climate forecasts reveal that for every degree of warming, Western Australian rainfall may decline 4%-7%. The effects of rising temperatures and declining rainfall will make agricultural production globally and in Australia much more challenging.
Departures from the long-term temperature mean have been changing with the frequency of cold month anomalies declining along with the size of those anomalies. Meanwhile, the size and frequency of the warm anomalies is starting to increase. The significant change in Australia’s temperatures has led to a decline in annual rainfall, driven by falls in winter and spring rain. Temperature extremes (above 37oC) have increased and are occurring earlier in the year, while the frequency of extreme cold temperatures is occurring more often and later in the year. Crimp said these extreme temperature events are shrinking the optimal flowering window for broadacre crops, while the changes in rainfall have led to declines in yield. Greenhouse gas emissions would need to be curbed significantly over the coming years to avoid temperatures in Australia being 3oC – 6oC warmer by 2100.