Draft legislation released by the powerful US House of Representatives Energy and Commerce Committee, proposes a cap-and-trade scheme leading to cuts equivalent to 30 per cent below 2005 levels by 2020.

The Australian Government proposes cuts of between 5 and 15 per cent below 2000 levels, depending on the level of international co-operation to tackle climate change.

While the proposed schemes differ in key ways, emissions trading experts said the US plan translated to a cut of up to 31 per cent below 2000 levels.

Andrew Macintosh, associate director of the Australian National University's Centre for Climate Law and Policy, said the US proposal was much more ambitious.

He said it would not be enough to reduce atmospheric carbon dioxide to 450 parts per million — the maximum level recommended by climate scientists — but was "about as much as you could expect the US to go for".

"It is certainly well beyond what the Rudd Government is talking about," he said.

"It is the sort of thing developed countries have to be talking about if they want to have a decent chance to avoid dangerous climate change."

Climate Institute chief executive John Connor said the US bill was more likely to give momentum to negotiations towards a new global climate agreement, due to be signed in Denmark in December.

"This is a smarter, stronger and more helpful package than the (Australian) Government currently has," he said.

The US proposal, put forward by Democrat Congressman Henry Waxman, would cut emissions to 20 per cent below 2005 levels by 2020 and 83 per cent by mid-century.

But unlike the Australian proposal, its headline target does not include credits for preventing logging in poor countries.

This is listed separately — as a 10 per cent cut below its 2005 emissions.

Also unlike Australia, the US would pay for these deforestation credits, with some of the revenue reaped from auctioning carbon permits to its polluting industries.