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.