PLEA Network

10 September 2015, The Conversation, Sure, winter felt chilly, but Australia is setting new heat records at 12 times the rate of cold ones. Spring feels like a welcome relief from an Australian winter that felt very cold and very long. Melbourne has just shivered through its coldest winter in 26 years and Canberra hibernated through more cold nights than any winter since 1997. But while it felt cold, it turns out we’ve just become accustomed to unusually warm conditions. My new study online in Geophysical Research Letters (with my colleague Andrew King) shows that Australia has been losing out on cold temperature records over the past 55 years. We investigated the frequency of new hot and cold temperature records for months, seasons and years, for each state and Australia as a whole, from 1910 to 2014. The results were straightforward. Record-breaking hot temperatures have outnumbered new cold records by a factor of 12 to 1 since the beginning of this century. The cause is also clear: global warming. Yet people’s ability to recognise climate extremes is easily affected by our perceptions. Riding my bike around frosty Canberra this winter felt brutally and unusually cold. But in reality it was only a bit colder than recent “warm” winters. Such misperceptions about climate extremes are common. During the record-breaking spring temperatures in Australia in 2013, Prime Minister Tony Abbott said: “…the thing is that at some point in the future, every record will be broken, but that doesn’t prove anything about climate change. It just proves that the longer the period of time, the more possibility of extreme events.” At first pass, this sounds like common sense. But statistically, it’s wrong. In an unchanging climate, new temperature records actually become less likely to occur with time, because each new record would be harder to beat in the absence of anything driving temperatures in a particular direction. Read More here