The Federal Government's Climate Commission has warned the window for limiting future and costly climate change is rapidly closing.

In its first report, titled The Critical Decade, the commission says the evidence that the planet is warming is now even stronger.

It warns global warming could cause global sea levels to rise up to one metre by the end of the century, higher than previously thought.

Chief commissioner Tim Flannery says humanity is almost surely the primary cause of global warming.

"There's agreement that there's a temperature increase, there's an agreement that it's human-caused," he said.

"We have exactly eight years and seven months to meet our target of minus 5 per cent, which is a very ambitious target."

To minimise the risk, the commission says Australia must decarbonise its economy and move to clean energy sources by 2050.

That means carbon emissions must peak in the next few years and then strongly decline.

And while the report acknowledges the science is advancing strongly, it notes there are still questions in the public arena.

"The public still seems to be confused about a few of those issues and I think that's partly due to uninformed opinion," Professor Flannery said.

"You get all sorts of people posing as having some expertise in climate science, whether they be taxi drivers speaking to me or people in the media who don't have the expertise.

"That is clouding the waters a little bit and slowing things down."

Climate scientist and commissioner Professor Will Steffen is concerned the science is being muddied in the media by many with no credentials.

"I don't think we have the luxury anymore of climate denialism. We need to get beyond this fruitless phoney debate in the media," he said.

Professor Steffen says the decisions made between now and 2020 will determine the level of severity of global warming.

"We've got to make some very important policy decisions," he said.

"We have to make some very important investment decisions this decade if we're to take advantage of this fleeting last opportunity to get this situation under control."

The national director of the Youth Climate Coalition, Ellen Sandell, says the report shows the critical need for action now.

"We really need to trust [people] who have decades of experience who are saying that it is caused by humans and we actually need to do something about it now," she said.

"Otherwise younger generations like my generation are not going to be able to have the same quality of life that our parents and grandparents have."

Fresh approach

The commission, established by the Government to promote the case for tackling climate change, is calling for a fresh approach to reducing carbon emissions.

It says that rather than focusing on interim targets based on percentage cuts, governments should commit to emitting no more than an agreed carbon dioxide "budget" by 2050.

It says this budget approach would allow greater flexibility and encourage investment in the most effective technologies rather than quick-fix solutions.

The report has also taken a blowtorch to the Opposition's direct action policy.

Opposition Leader Tony Abbott's plan to reduce pollution is predominantly focused on storing carbon in soils and trees.

The commission says while returning carbon to land ecosystems can help restore degraded soils and improve the land's productivity, it does not equate to reducing fossil fuel emissions.

It says this is because because additional carbon is not permanently removed from the atmosphere-land-ocean cycle and could possibly lock in more severe climate change for the future.

But Mr Abbott says the report does not undermine the Coalition's strategy for reducing carbon emissions.

"The argument here is not about climate change; the argument here is about how to deal with it," he said.

"The Climate Commission report says direct action is a rapid way of reducing emissions."

The commission releases the 70-page Critical Decade report today.