Saturday, June 29, 2013

Humans play role in Australia’s “angry” hot summer

University of Melbourne Newsroom: Human influences through global warming are likely to have played a role in Australia's recent “angry” hot summer, the hottest in Australia’s observational record, new research has found.  The research led by the University of Melbourne, has shown that global warming increased the chances of Australians experiencing record hot summers such as the summer of 2013, by more than five times.

Lead author, Dr Sophie Lewis from the University of Melbourne and the ARC Centre of Excellence for Climate Systems Science said the study showed it was possible to say with more than 90 per cent confidence, that human influences on the atmosphere dramatically increased the likelihood of the extreme summer of 2013. “Our research has shown that due to greenhouse gas emissions, these types of extreme summers will become even more frequent and more severe in the future,” she said.

The study Anthropogenic contributions to Australia’s record summer temperatures of 2013 has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union. The study used climate observations and more than 90 climate model simulations of summer temperatures in Australia over the past 100 years.

Professor David Karoly, a co-author on the paper said the observations, coupled with a suite of climate model runs comparing human and natural influences in parallel experiments, indicated we have experienced a very unusual summer at a time when it was not expected. “This extreme summer is not only remarkable for its record-breaking nature but also because it occurred at a time of weak La Niña to neutral conditions, which generally produce cooler summers,” he said. “Importantly, our research shows the natural variability of El Niño Southern Oscillation is unlikely to explain the recent record temperatures.”...

A public clock in Melbourne showing 45°C on 7 February 2009, the day that Melbourne reached its highest ever recorded temperature of 46.4 °C (115.5 °F). Shot by Melburnian, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

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