A study ranks Australia among the worst nations for damaging its environment.

The Adelaide University study names Brazil, the United States, China and Indonesia as the worst countries.

The study findings, published in a science journal, use indicators including species and forest loss, water pollution and carbon emissions to determine the rankings, which put Australia at number nine.

Professor Corey Bradshaw from Adelaide University says Australia has some of the highest global carbon emissions.

"We also have one of the highest rates of mammalian extinctions and threat levels in the world and we have a very dry continent and we don't have a lot of water," he said.

"We have some of the highest per capita water use in the world and that's just not sustainable.

"This gets back to the ideas of how many people can a place like Australia hold? We are mostly a desert, despite the fact that we are a large country."

Professor Bradshaw says Australia will need to change its practices if it hopes to sustain 35 million people by 2050.

"If we manage to reduce our consumption per capita, if we get a lot cleverer about our use of water, about how we grow food, how we generate power and reduce our emissions, I think those sorts of numbers are certainly feasible," he said.