Australia needs to significantly cut its carbon emissions now if it is keep pace with the most recent announcement from the United States, especially as climate change is proceeding faster than first thought, a Charles Sturt University (CSU) climate expert claims.

"Australia's current proposal to cut five per cent by 2020 will not get us on a trend to match the US announcement to cut their emissions by 30 per cent by 2030," says Professor Kevin Parton from the University's Institute for Land, Water and Society.

"Australia would need a cut of about 12 per cent by 2020 to match the US, but a larger cut would be better given the state of our rapidly changing climate.

"And one way to achieve a 12 per cent cut is to get the 33 firms that generate the most greenhouse gases in Australia – the biggest coal fired electricity producers, miners and metal processors - to each cut their emissions by 25 per cent."

Professor Parton believes the proposal by US President Obama may be too little too late.

"We have just had the hottest 24-month period on record, and other climate change indicators are at the top of their expected range," he said.

"Although an emissions trading scheme would be the least-cost method of reducing greenhouse gas emissions, this has been ruled out by the federal government, so alternatives like regulating the largest emitters need to be considered."

Professor Parton has commented widely on climate change, carbon trading and the former emissions trading scheme.