Extreme heat may render societies unviable by 2090 if climate change isn't addressed, a leading Australian scientist says.
Searing Australian heatwaves will feel cool by 2090 if greenhouse gas emissions aren't reduced, a leading climate scientist says.
A new report reveals Australia's hottest year on record would not have happened without climate change.
The country experienced its hottest day, month, season and calendar year in 2013, registering a mean temperature 1.2C above the 1961-90 average.
The Climate Council says recent studies show those heat events would have occurred only once every 12,300 years without greenhouse gas emissions from human activities.
Professor Will Steffen says life will be tough by 2090 if emissions aren't reduced to stabilise the climate.
"What you consider an extreme heat event now would be a normal summer by the middle of the century," the author of Quantifying the Impact of Climate Change on Extreme Heat in Australia told reporters on Saturday.
"By 2090, when my grandkids are around, that's going to be a cool summer."
"You don't want to live in that world.
"There's even questions in the research community about whether societies will be viable in that world."
Based on analyses of data and model outputs, the report says climate change triples the odds that heatwaves of the 2012-13 Australian summer will happen as frequently as they do.
It also doubles the chances of them being as intense.
Mr Steffen found record hot days have doubled in Australia the last 50 years, and that during the past decade heat weather records were set three times more often than cold ones.
The report also claims heatwaves across Australia are becoming hotter, lasting longer, occurring more often and starting earlier.
Mr Steffen said Australia must harness its rich renewable energy resources, such as solar, and phase out fossil fuels like coal.
Climate Council chief councillor Professor Tim Flannery said one of the key ways to combat the issue was a price on carbon.
"But it's not something that's going to happen overnight, this is going to take years and decades to reduce the pollution to where it needs to be," he said.
HOW AUSTRALIA FEELS THE HEAT, COMPARED TO 1950-80:
* Average intensity of a Melbourne or Sydney heatwave, up 1.5C
* Average intensity of an Adelaide heatwave, up 2.5C
* Average intensity of a Brisbane heatwave, up 1C
* Average intensity of a Perth heatwave, up 1.5C