Australian scientists on Tuesday warned half the planet could "simply become too hot" for human habitation in less than 300 years.

New research by the University of New South Wales has forecast the effect of climate change over the next three centuries, a longer time horizon than that considered in many similar studies.

It suggested without action to cut greenhouse gas emissions, mankind's activities could prompt average temperatures to rise as much as 10 to 12 percent by 2300.

"Much of the climate change debate has been about whether the world will succeed in keeping global warming to the relatively safe level of only two degrees Celsius by 2100," said Professor Tony McMichael, from the Australian National University (ANU), in an accompanying paper also published in the Proceedings of the National Academy of Sciences (PNAS).

"But climate change will not stop in 2100, and under realistic scenarios out to 2300, we may be faced with temperature increases of 12 degrees or even more."

McMichael said if this were to happen, then current worries about sea level rises, occasional heatwaves and bushfires, biodiversity loss and agricultural difficulties would "pale into insignificance" compared to the global impacts.

Such a temperature rise would pose a "considerable threat to the survival of our species," McMichael said, because "as much as half the currently inhabited globe may simply become too hot for people to live there."

The research, produced in partnership with the Purdue University in the United States, has been published in the U.S.- based scientific journal Proceedings of the National Academy of Sciences (PNAS) on Tuesday.