Australian Greens Leader Christine Milne says Joe Hockey can't expect to grow Australia's economy with policies that deepen inequality and worsen global warming.

"Climate has stolen the show at the G20, in spite of the Abbott government," said Senator Milne.

"Joe Hockey and Tony Abbott are completely wedged between their big business mates who want to carry on polluting for profit, and the world leaders who've come to Australia declaring it's time for a massive shift.

President Obama's realism on global warming has shown up the small minded Prime Minister of Australia, says Greens Leader Christine Milne.

"Barack Obama has shown just how small and last century Tony Abbott is," Senator Milne said.

"The G20 is meant to be addressing the overwhelming problems of our age but Tony Abbott is showing what a small minded and insignificant player he is by whining about domestic politics instead.

The leaders of the Australian and New Zealand Green parties are calling on their respective governments to take action on climate change and inequality at the G20 meeting in Brisbane this weekend - topics that are absent from the agenda of the meeting of the world's richest nations.

"The Prime Ministers of our two countries may not be prepared to talk about the issues that are overwhelming the planet, but the Greens are. So are other world leaders. As the G20 host, Tony Abbott needs to get real," said Australian Greens Leader Christine Milne.

The Australian Greens are congratulating the US and China on their agreement to act on global warming and say it's not too late for Australia to get on board.

"This should be a massive wake-up call to Tony Abbott. His continued climate denial and his destruction of the environment is reckless," said Greens Leader Christine Milne.

"Tony Abbott is so busy unwinding Australia's climate policies that he failed to notice the global economy is changing around him. He is risking billions of dollars in investment and thousands of jobs.

Greens Leader Christine Milne says Prime Minister Abbott is setting Australia up to fail in the eyes of the G20, by ignoring global warming and playing domestic politics on the international stage.

"Tony Abbott is promising the G20 he'll deliver on some of his cruel budget cuts that have already been denounced by the Senate and the community as unacceptable," said Senator Milne

"Using the G20 to wedge the Senate is another crash or crash through tactic, but it's going to backfire on the Abbott government.

Australian Greens Leader Christine Milne has backed the Intergovernmental Panel on Climate Change on its most comprehensive scientific assessment to date, which says we will stand no chance of preventing catastrophic
warming if we do not leave the majority of the world's fossil fuel reserves in the ground.

"Coal is bad for humanity, and so is Tony Abbott's denial of global warming science," said Senator Milne.

The Australian Greens say coal miner Clive Palmer has helped our climate denier Prime Minister to demolish emissions trading in favour of a complete sham that benefits coal miners and polluters.

"Coal miner Clive Palmer has worked with the climate denier Abbott government to deliver a huge win for coal miners and big polluters," Greens Leader Christine Milne said.

"The dodgy and misnamed Direct Action policy will not reduce pollution. It has absolutely no substance at all.

"While Hydro Tasmania has said moves to water down the RET wasn't the deciding factor in pursuing the King Island wind farm, Tasmanians should be under no illusion that the Abbott government's ruthless attack on the RET has undermined investment certainty," Senator Milne said.

"A cut to the RET will impact future investment in the state.

"In its recent profit statement Hydro pointed out that uncertainty around the RET was one of the "challenging conditions" which would affect future profits, and it will.