This time last year, it was announced that Australia had experienced its hottest spring on record.
Well, guess what? It’s happened again. The spring of 2014 was hotter still and is the new record-holder.
Across Australia, the average temperature for September to November 2014 was 1.67C warmer than the long-term average. That made it 0.1C hotter than the previous record spring of 2013, and the hottest since high-quality records began in 1910.
As the Bureau of Meteorology’s special climate statement points out, unusual warmth was seen across almost the entire country. It was the hottest spring on record in South Australia and Western Australia, as well as being one of the eight hottest in every other state and territory.
So did climate change play a role in this record?
Following the record heat of 2013 in Australia, a slew of studies were conducted to investigate whether a human fingerprint could be detected. Five independent investigations into aspects of the 2013 heat all came to the same conclusion: humans were largely to blame.
In one study (see section 9 here), climatologists Sophie Lewis and David Karoly showed that human-induced climate change had increased the risk of an unusually hot spring (like that of 2013) by a factor of at least 30. They did this by comparing model simulations designed to replicate the actual world with modified simulations replicating a world without humans.
Spring 2014 was hotter still and we can be confident that human activity, through greenhouse gas emissions, has loaded the dice in favour of yet more hot weather. In line with Lewis and Karoly’s finding for last year, human activity was very likely a significant factor in the record-breaking spring we have witnessed across Australia in 2014.
Over the coming years we can expect to have more record-breaking hot temperatures in Australia as greenhouse gas concentrations rise further and the human influence on the climate becomes even clearer.