More Extremes Of Heat, Wind, Floods, Bushfires To Follow Australia’s Hottest Year

Photo: Chris Hyde/GETTY

A year of records for Australia: the hottest month on record, seven days in a row where the national average exceeded 39 degrees Celsius, an early end to winter, the hottest consecutive 12 months on record, the hottest spring on record.

And the largest anomaly from the monthly mean temperature was September 2013 which was 2.75 degrees Celsius above the overall September mean, the highest anomaly for any month on record.

More record breaking climate is on its way. Consistently higher sea surface temperatures around Australia mean that hotter conditions will continue. It could also mean flooding, high winds, drought and bushfires.

Roger Jones, from Victoria University and a Convening Lead Author (CLA) on the Intergovernmental Panel on Climate Change’s Working Group II Fifth Assessment Report to be released later this year, says Australians should be concerned.

“While the increases in average temperatures may seem to be benign – heat waves are increasing faster than those averages,” Professor Jones says.

“Why heat waves are longer and hotter than anticipated is not yet clear, but they are contributing to greater fire danger and heat stress than projected by climate impact studies, affecting animals, plants and humans.”

Higher sea surface temperatures can also often manifest in greater extremes of rainfall, particularly in northern Australia.

“This vigour was reflected in a number of flooding events around the nation,” Professor Jones says.

“However, in the southern mainland, where I am at the moment, the locals are heralding a return to drought conditions and hoping those conditions do not last.

“High winds during spring and early summer that caused a great deal of crop damage throughout southern Australia were associated with strong frontal systems.

“These are hopefully temporary, but are affecting growers still recovering from recent droughts and floods.

“While many climate extremes cannot be directly attributed to a changing climate, the burden of extremes Australia is experiencing is a product of climate change and requires a coordinated national response.”

The 2013 record high is also remarkable because it occurred not in an El Nino year (where a warm ocean current can push up temperatures), but a normal year.

Professor David Karoly, from the School of Earth Sciences at University of Melbourne, says analysis has been made of the temperature record using simulations with nine different climate models that represent the natural variability of Australian average temperatures.

He says these indicate that greenhouse climate change vastly increased the odds of setting a new temperature record.

“In the model experiments, it is not possible to reach such a temperature record due to natural climate variations alone,” Professor Karoly says.

In simulations with no increases in greenhouse gases, none of the more than 13,000 model years analysed reach the record temperature observed in 2013.

And in simulations for 2006 to 2020 with natural variability and human influences, including increases in greenhouse gases, such records occur approximately once in every ten years.

“Hence, this record could not occur due to natural variability alone and is only possible due to the combination of greenhouse climate change and natural variability on Australian average temperature.”

These indicate that greenhouse climate change vastly increased the odds of setting a new temperature record.

“In the model experiments, it is not possible to reach such a temperature record due to natural climate variations alone,” Professor Karoly says.

Sarah Perkins, a research associate in the ARC Centre of Excellence for Climate System Science at the University of NSW, says the amount of temperature records broken in the last year is extraordinary.

“Studies have already shown that the risk of summers like 2013 occurring have increased by up to five-fold, because of human induced climate change,” she says.

She compares this to the increased risk of cancer from smoking. “Like medical science has proven that tobacco smoke greatly increases the risk of contracting cancer, climate science has proven that higher atmospheric greenhouse gas concentrations increases the risk of more extreme temperatures, more often.”

Professor Ian Lowe, emeritus professor of science, technology and society at Griffith University, and President of the Australian Conservation Foundation, says there is no rational basis for the claim that warming has slowed in recent years.

“The October bushfires in the Blue Mountains and the recent Queensland heatwave are reminders of the threat to Australia if present trends continue,” he says.

“We have a clear responsibility to strengthen measures to reduce local greenhouse gas production, especially the Renewable Energy Target and the Clean Energy Finance Corporation.

“We should also play a responsible role in the global effort to slow climate change by immediately prohibiting new fossil fuel export projects.”

Watch the video from the Bureau of Meterology, explaining Aastralia’s hottest year:

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