A "shocking" warning that heatwave deaths in Sydney could skyrocket by more than 400 per cent has brought the issue of urban heat back into sharp focus, particularly in the city's west.

The dire prediction comes from the Australian government's first-ever National Climate Risk Assessment , released on Monday, which modelled the impact of climate change under three different warming scenarios.

Heatwaves already cause more deaths in Australia than all other extreme events combined.

Even under the best-case scenario — 1.5 degrees Celsius of global warming — the assessment warns heat-related deaths in Sydney would double.

Under 3C of warming, it predicts heat-related deaths in Sydney could rise by 444 per cent.

The Climate Change Authority said the world is on track to see 2.9C of warmi

See Full Page