Scientists forecast that the type of extreme hot weather we have until now regarded as unusual will become a normal pattern in many regions, occurring every year or two.
Heatwaves such as have been experienced across many part of Australia already this year are already hotter, longer, more frequent and occurring earlier in the season.
Over the past 100 years heatwaves have caused more deaths than any other natural hazard.
A Climate Council report just released says this shows that the frequency of record hot days are now more than three times the frequency of record cold days.
The CSIRO and Weather Bureau have found that since 1950 the annual number of record days across Australia has more than doubled and maximum and minimum temperatures have increased by 0.9 per cent.
The south of the country is feeling the impact even more, with hot weather in Adelaide, Melbourne and Canberra having already reached levels predicted under warming scenarios for 2030.
Chief climate councillor Professor Tim Flannery said that climate change had made heatwaves worse over the past 60 years.
“In a stable climate that would not be happening,” Professor Flannery said.
Transport, electricity services, wildlife and the Great Barrier Reef are all affected by heatwaves.
“We see another impact of heatwaves in an extended bushfire season,” Professor Flannery said.
The Climate Council reports comes a day after the United States Secretary of State John Kerry described climate change as a “weapon of mass destructions.”
It also follows the statement by a leading British economist Lord Nicholas Stern that bushfires and floods were a manifestation of the devastation of climate change.
The Climate Council’s latest report, Heatwaves: Hotter, Longer, More Often, which was co-authored by Professor Will Steffen, Professor Lesley Hughes and Dr Sarah Perkins, delivers four key findings.
First, climate change is already increasing the likelihood and severity of heatwaves across Australia.
Second, heatwaves have widespread impacts including increased deaths, reduced workplace productivity, damage to infrastructure such as transport and electricity systems, mortality of heat-sensitive plants and animals, and stress on agricultural systems.
Third, record hot days and heatwaves are expected to increase further in the future.
And finally, limiting future increase in heatwave activity requires urgent and deep cuts to greenhouse-gas emissions.
The report describes heatwaves as a ‘silent killer’ and says they cause the greatest number of deaths of any natural disaster type in Australia, and have significant impacts on infrastructure, agriculture and biodiversity.
The report says the Bureau of Meteorology has dubbed heatwaves “the most under-rated weather hazard in Australia”.
It says that while heatwaves do not result in obvious violent effects on the landscape, unlike many other weather-related disasters such as high-intensity storms and bushfires, their impacts on health, the workplace, infrastructure, agriculture, and the environment are serious, costly and long lasting.
Professor Steffen said the challenge to decarbonise Australia’s future must be met if the country is to minimise the risk of worsening heatwaves and other extreme events for ourselves, our children and grandchildren.
“It’s time to get on with the job,” he added.
