US President Barack Obama and his Chinese counterpart Xi Jinping reached an agreement on clean energy on Wednesday, with China making history by announcing its first deal on curbing carbon emissions.

In a statement issued by the White House, the US has adjusted its target to cut net greenhouse gas emissions 26 to 28 per cent below 2005 levels by 2025. China targets to peak carbon emissions around 2030 and to increase the non-fossil fuel share of all energy to around 20 per cent by 2030.

In Australia, Opposition Leader Bill Shorten used the announcement to criticise the Abbott Government for leaving climate change off the agenda for this week’s G20 summit.

Mr Shorten said Tony Abbott's "flat-earth views" were out of touch with the rest of the world's leaders, urging him to include climate discussions in the summit agenda.

“While the United States and China show global leadership, Tony Abbott is sticking his head in the sand,” he said.

“At the G20 this week, Australia will hold the embarrassing title of being the only nation going backwards on climate change. With China and the United States representing around one-third of the global economy and over 40 per cent of global emissions, there will be significant momentum to deal with climate change in Brisbane.

"Climate change is not just an environmental issue. It is a security issue and it is absolutely an economic issue."

'Tony Abbott is sticking his head in the sand'

Greens Leader Christine Milne also urged Mr Abbott is take action, labelling the China-US agreement as a "massive wake-up call".

Mr Abbott – whose election pledge to abolish he carbon tax was fulfilled in July - has previously conceded that climate change was likely to be raised at the G20, but said the event would focus on economic security.

Environment Minister Greg Hunt welcomed the announcement by the US and China, adding that the government would "consider" Australia’s post-2020 emissions reduction targets ahead of next year's climate change conference in Paris.

"In the meantime, what's important for Australia is that we have replaced Labor's ineffective and costly carbon tax with a policy that will actually deliver significant emissions reductions," he said in a statement.

The Abbott Government’s negotiations with the Opposition on the renewable energy target broke down on Wednesday morning, with Mr Shorten walking away.

Addressing media in Melbourne, he said the Abbott Government was not interested in supporting the renewable energy industry.

“Even though we have tried our best to be bipartisan, we will not sacrifice the Renewable Energy Target and industry just because Tony Abbott is a climate change sceptic and election promise breaker,” he said.

"We formed the view that the government only had one plan for renewable energy, that is to destroy the industry."

'This is an ambitious goal, but it is an achievable goal'

President Obama urged other countries to be ambitious with climate policy when addressing media in Beijing.

“This is an ambitious goal, but it is an achievable goal,” he said.

His pledge follows a number of shifted or missed goals to cut emissions.

Its greenhouse gas emissions increased last year, despite Washington setting emissions reduction goals during a climate summit in 2009.

The deadline for President Obama's new pledge is in more than a decade's time but he only has two years left in his presidency and faces a Congress controlled by opposition Republicans in both houses, which will make passing crucial environmental legislation more difficult.

Much of his action on climate change so far has been done with executive orders rather than co-operation from an often confrontational legislature.

While it was the first time China agreed to a target date for emissions to peak - officials have previously only spoken of doing so "as soon as possible" - the commitment was qualified, leaving considerable room for manoeuvre.

China has trumpeted its efforts to reduce dependence on coal and oil in the past, and is the world's largest hydropower producer, with a growing nuclear sector.

But economic growth remains a vitally important priority and has seen demand for energy soar.

The European Union pledged last month to reduce emissions by at least 40 percent by 2030 compared with 1990 levels.

But efforts to make meaningful progress on climate change will by stymied unless the US sets "a concrete and ambitious" goal to reduce its greenhouse gas emissions, Connie Hedegaard, EU climate commissioner, said in October.

The EU accounts for 11 per cent of the world's greenhouse gas emissions, compared to 16 per cent for the United States and 29 per cent for China.

With AFP.