4 October 2017

Melbourne and Sydney should prepare for 50-degree Celsius days

Posted by llipuma

This map shows peak land surface temperatures between February 7 and 14, 2017, a period when some of the most extreme heating occurred in Australia’s summer of 2016-2017. A new study finds Melbourne and Sydney should prepare for 50-degree Celsius (122-degree Fahrenheit) summer days under the Paris Agreement global warming limit of 2 degrees Celsius (4 degrees Fahrenheit).
Credit: NASA Earth Observatory.

By Will Wright

A new study warns that Melbourne and Sydney should prepare for 50-degree Celsius (122-degree Fahrenheit) summer days under the Paris Agreement global warming limit of 2 degrees Celsius (4 degrees Fahrenheit).

The new study, published in Geophysical Research Letters, a journal of the American Geophysical Union, assessed the potential magnitude of future extreme temperatures in Australia under Paris targets of an increase in global temperatures of 1.5 and 2 degrees Celsius (3 and 4 degrees Fahrenheit) above pre-industrial levels.

“Major Australian cities, such as Sydney and Melbourne, may experience unprecedented temperatures of 50 degrees Celsius under 2 degrees of global warming,” said Sophie Lewis, a climate researcher at the Australian National University in Canberra, Australia and lead author of the new study. “The increase in Australian summer temperatures indicates that other major cities should also be prepared for unprecedented future extreme heat. Our climate modeling has projected daily temperatures of up to 3.8 degrees Celsius [7 degrees Fahrenheit] above existing records in Victoria and New South Wales, despite the ambitious Paris efforts to curb warming.”

Lewis said immediate climate action internationally could prevent record extreme seasons year after year.

“Urgent action on climate change is critical – the severity of possible future temperature extremes simulated by climate models in this study poses serious challenges for our preparedness for future climate change in Australia,” she said.

Lewis said the record hot Australian summer of 2012 to 2013 was made more likely due to human-caused greenhouse warming, and such an event was expected to occur more frequently under future warming.

“One of the hottest years on record globally in 2015 could be an average year by 2025,” she said.

Andrew King, a climate researcher at the University of Melbourne and co-author of the new study, said the research team used a combination of observations and modeling to assess how the magnitude of record-breaking events may change in the future.

“Previous scientific studies have focused on how current temperature extremes have been impacted by climate change, or on how the frequency of these current extremes will change in the future,” King said. “This study takes a different approach and examines how the severity of future temperature extremes might change in the future.”

— Will Wright is a senior media communications officer at the Australian National University. This post originally appeared as a press release on the ANU website.