What percent of Australia is uninhabitable?

Approximately 40 percent of the country is uninhabitable desert.

And here is a dire prediction for the continent:

Parts of populated Australia will become uninhabitable unless urgent action is taken to reduce greenhouse gases, the director of a leading think tank warned here Monday.
Australia Institute executive director Clive Hamilton told an environmental task force that Australia faced a bleak future, with major population movements because of extreme weather events and the rise of insect-borne diseases.

"I think parts of Australia which are currently inhabited will be uninhabitable," he said at the International Climate Change Taskforce meeting here.

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