Failure to act on climate change will cost Australia dearly as droughts, flooding and other natural disasters become more frequent and intense, a new report says.

The bushfires now engulfing parts of Queensland and last week’s torrential rain in Sydney add to a mounting list of evidence that global warming is already upsetting national weather norms, the paper by the Medical Journal of Australia says.

“Australia is unusual in the sense that each of these hazards can be responsible for a probable maximum loss event that may cause significant damage to the community,” the report says.

Citing several studies, the report – a collaboration with global medical journal The Lancet – says many regions may be prone to increased flooding or storms and bushfires.

University of Sydney Professor of Climate Change and Mental Health Helen Berry, one of the report’s authors, says it “makes no sense” that the country is not acting on global warming.

“Right now, Queensland is reeling from devastating unseasonable fires while Sydney mops up after getting a whole month’s rain in two hours,” she said.

“Continuing to ignore scientists’ warnings makes no sense in a country that is so wealthy and intellectually rich, yet so vulnerable to climate change.”