Bigger carbon cuts needed, report says

The gap between climate change commitments and what scientists say is necessary is underlined in a new report that estimates Australia would need to make emissions cuts of at least 27 per cent by 2020 and 82 per cent cut by 2030 to play its part in averting global warming.

The report by European consultancy Ecofys comes as the Climate Change Authority prepares to release draft recommendations this week on how much and how quickly Australia should be cutting emissions.

The authority, chaired by former Reserve Bank governor Bernie Fraser, will release the report despite the new Coalition government having pledged to abolish it as part of its dismantling of most Labor-period climate change policy.

Economists such as Ross Garnaut and Frank Jotzo have recommended to the authority that Australia's 2020 greenhouse target should be strengthened from the minimum 5 per cent cut backed by both main parties to more than 15 per cent, based on assessments of what other countries are doing.

The Ecofys report, commissioned by environmental group World Wildlife Fund, finds that Australia has already emitted at least two-thirds of what it could reasonably ever emit under a global ''carbon budget'' - the maximum emissions that can be released in coming decades to give the world a chance to limit global warming to less than 2 degrees.

If emissions remain at their current level, Australia's estimated long-term budget of 18 billion tonnes of carbon dioxide would be used up in about a decade.

It estimates Australia would need to cut emissions by between 27 and 34 per cent below 2000 levels by 2020, and between 82 and 100 per cent by 2030. By 2050 it is likely Australia would be expected to have zero emissions and to be drawing carbon dioxide from the atmosphere.

WWF Australia's Kellie Caught said the country had nearly blown its carbon budget and should make at least a 25 per cent cut - the top end of the range backed by the Coalition and Labor - if it was serious about tackling the problem.

''Just as we need a stable plan for our economic bottom line, we also need a stable long-term approach to our carbon budget,'' she said.

The Climate Change Authority is taking a different approach to Ecofys to assessing what Australia's climate target should be. While the consultants looked just at Australia's share of the cut needed, the authority recommendation is based on an assessment of climate science, what other countries have promised to do and the economic and social implications of the proposed cut.

The authority will call for public submissions before making its final recommendation in February, if it survives that long.