LONDON (Thomson Reuters Foundation) - China and the United States are expected to give the Paris climate change agreement a big push forward as the world’s largest economies gather for the G20 summit this weekend, including potentially jointly announcing their ratification of the deal and action to curb fossil fuel subsidies, experts say.

U.S. President Barack Obama meets with China's President Xi Jinping at the G20 Summit in St. Petersburg September 6, 2013. REUTERS/Kevin Lamarque

With China – which has shown growing international leadership on climate change – hosting the summit for the first time, “we can expect climate and energy to be front and center”, said Joanna Lewis, a specialist at Georgetown University on energy and environmental issues in China.

The Sept. 4-5 summit is also the last for U.S. President Barack Obama, who hopes to cement action on climate change as one of his legacy issues, experts say.

China and the United States, the world’s two biggest contributors to climate change, have made a joint political push to drive action on the problem since 2014, when they made their targets for the Paris agreement public at the same time.

“The U.S. and China are poised to lead the way in the G20 (on climate action) so other countries will follow,” Lewis told journalists by telephone.

But with China still accounting for more than half of the world’s coal use, and G20 countries so far committed to only a sixth of the emissions cuts needed to hold global temperature to “well below 2 degrees Celsius”, as agreed in Paris, much more needs to be done, said Lutz Weischer, head of international climate policy at Germanwatch, an advocacy group that tracks climate action.

In particular, planned new coal-fired power plants within the G20 would nearly double coal capacity if built, and would make it “virtually impossible” to keep warming even to 2 degrees, said a report issued Thursday by the Climate Transparency consortium.

“In the real world, there is still a long way to go, particularly for the G20, and they need to reflect that in a more serious way,” Weischer told journalists.

Li Shuo, a climate and energy specialist with Greenpeace East Asia, said China in particular should commit to more ambitious carbon-cutting goals under the Paris agreement, as the country’s progress suggests it could start decreasing its emissions by 2020 rather than 2030, its current goal.

Climate change will be far from the only issue on the G20’s plate at talks on Sunday and Monday. Other challenges - from the slowing world economy to terrorism, refugees and political uncertainty in members such as Britain, the European Union and Brazil – will likely be at the forefront.

But with China expected to meet its Paris climate commitment to peak emissions ahead of schedule, as it slowly reduces its use of coal and pushes hard on renewable energy investment, experts say it is likely to use the summit as a way to highlight its successes and pressure others.

PARIS MOMENTUM

G20 countries produce about 80 percent of climate-changing greenhouse gas emissions, with China and the United States alone responsible for 38 percent, noted Andrew Steer, president of the World Resources Institute (WRI).

Getting more G20 members to ratify the Paris climate deal could boost momentum for it to take effect early, perhaps even by the end of this year or early next, he added.

That is considered increasingly important as the world continues to break temperature records on an almost monthly basis and struggles with more extreme weather, worsening coral bleaching, and other impacts that suggest climate change is advancing faster than anticipated.

For the milestone Paris climate agreement to come into effect, 55 countries representing 55 percent of the world’s emissions must ratify it.

So far 23 countries have done so, but 55 nations accounting for 58 percent of emissions have indicated they will approve the deal by the end of the year, said Andrew Light, a senior fellow at WRI and a former U.S. State Department climate adviser.

“The U.S., China and others have said they will meet this timeline. The question is whether all G20 countries will make a similar commitment,” he said.

Countries such as Brazil and Ukraine are now going through domestic steps toward ratification, he said, though getting the deal approved in the European Union will be more complex, as every member state needs to agree first.

SUBSIDIES DEADLINE?

G20 countries – which represent 82 percent of the world’s GDP - are also facing pressure to declare a deadline to phase out the fossil fuel subsidies they provide, which critics say hurt investment in clean energy and slow efforts to reduce the use of fossil fuels.

In recent days, investors managing $13 trillion and insurers handling more than $1.2 trillion in assets have called for G20 countries to announce a deadline to end the subsidies.

“Climate change... represents the mother of all risks – to business and to society as a whole,” warned Mark Wilson, CEO of insurer Aviva, in a statement. “And that risk is magnified by the way in which fossil fuel subsidies distort the energy market.”

Leaders in the G20 agreed in 2009 to phase out fossil fuels, but are yet to set a firm date, although G7 leaders have said they would do so by 2025, as part of a broader agreement announced last year to decarbonize the global economy.

Some 30 countries around the world have taken steps to cut subsidies in the last three years, from India, which eliminated diesel subsidies in 2014, to Germany, which aims to remove coal subsidies by 2018, said Helen Mountford, programme director for the New Climate Economy initiative and a WRI economist.

China is also expected to push at the summit for broader action on “green finance”, to help ensure that more of the anticipated $90 trillion-worth of new infrastructure to be built by 2030 is low-carbon, Steer said.

“If we’re to move from today’s high-carbon, low-efficiency world economy to tomorrow’s high-efficiency, low-carbon world economy, quite a lot needs to shift,” he said.