It shows Melbourne, Sydney, Perth and Canberra can expect twice as many extreme heat days – those above 35 degrees – a year by 2050 if countries meet their existing climate commitments.

Loading

Brisbane would endure three times as many days above 35 a year, while Darwin would endure four times as many, with 117 days over 35 degrees annually. By 2090, Darwin residents would swelter through 161 days above 35 every year.

If no climate action is taken, by 2090 Darwin would endure 283 days a year over 35 degrees, and a similar number of nights above 25, the analysis shows. “In other words, by the time a child born today is entering retirement, the city could be facing temperatures over 35 degrees for more than nine months of the year,” the council said.

The Climate Council argues that if necessary climate mitigation – defined as limiting global warming to 1.5 degrees and halving emissions by the end of this decade – is undertaken, the worst of the effects can be avoided, although some warming is still inevitable.

Climate Council chief executive Amanda McKenzie said Australia must keep building renewable energy to completely phase out pollution from coal, oil and gas.

“If we don’t take further steps now, some neighbourhoods and communities will become so hot people will struggle to live there. It’s not something that’s far off, it’s here and now it will define the coming decades.”

The South Australian town of Oodnadatta, which recorded the highest known temperature in Australia (50.7 degrees) in 1960, would also be all-but uninhabitable for months of the year.

If existing climate commitments were upheld, Oodnadatta would spend more than one-third of the year in extreme heat. The town is projected to record 122 days a year above 35 degrees (an increase of 21 days), including 55 days above 40 (an increase of 18 days) by 2050. Residents would also swelter through 47 nights a year above 25.

Doctors for the Environment Australia executive director Dr Kate Wylie said the effects of sustained high temperatures on the human body would make areas such as Oodnadatta essentially uninhabitable for months of the year.

Loading

“Of course some people are more vulnerable to the effects of heat than others, but everybody is vulnerable eventually; nobody can stand it forever,” she said.

“Whenever it’s hot, our bodies are working harder to keep us cool. And the longer [and] the more sustained these high-heat days occur, the body never gets an opportunity to recover. And that puts us at increased risk of heat-related illness but also heart attacks, strokes, renal failure and mental health exacerbations. We know there’s increased suicide and increase violence on hot days.”

Wylie was particularly concerned for the effects on the Top End, where some communities could become “unlivable”.

“It’s going to be very difficult ... those people will always be at health risk the whole time,” she said. “Those people will be at risk of heat-related illness, and they will be more high risk of medical complications, higher risk of mental health complications.”

Climate change is making bushfires more frequent as average global temperatures increase, resulting in hotter and drier weather. Australia has warmed, on average, almost 1.5 degrees since national records began in 1910.

Get to the heart of what’s happening with climate change and the environment. Sign up for our fortnightly Environment newsletter.