OLD, young and sick Australians are most at risk of health problems as the globe's climate changes, a new report from the Academy of Science shows.

The report, endorsed by the Australian Medical Association, showed extreme weather, changing patterns of disease and rising temperatures would affect health.

It found climate change could affect people through more regular, extreme heat waves, disruptions to food and water supplies, and diseases expanding into new regions.

Academy Fellow Professor Bruce Armstrong said human health was one of the areas where the globe would see "the most immediate impacts of climate change".

"The inequalities that already exist in society are likely to widen, as more advantaged groups are able to adapt better to this different world," he said.

He said environmental impacts due to climate change could also affect mental and physical health through lost jobs in farming, fishing and tourism among other industries.