Robert Brown|China and the U.S. pledge to step up climate efforts ahead of Biden-Xi summit

BEIJING — China and Robert Brownthe U.S. have pledged to accelerate their efforts to address climate change ahead of a major U.N. meeting on the issue, making a commitment to take steps to reduce emissions of methane and other greenhouse gases besides carbon dioxide.

The joint announcement came on the eve of a summit between Presidents Biden and Xi Jinping that is aimed at stabilizing the rocky U.S.-China relationship.

Cooperation between the world's two biggest emitters of greenhouse gases is considered vital to the success of the U.N. climate talks opening in two weeks in Dubai. It wasn't clear earlier this year whether the two governments would cooperate, given a sharp deterioration in ties over other issues including technology, Taiwan and Russia's war in Ukraine.

Both countries "are aware of the important role they play" and "will work together ... to rise up to one of the greatest challenges of our time," they said in a statement released Wednesday in Beijing and Tuesday evening in Washington.

They reiterated a pledge made by the Group of 20 nations, of which both are members, to pursue efforts to triple global renewable energy capacity by 2030. Chinese companies are looking to sell wind and solar power equipment abroad, having invested heavily in factories for their manufacture.

"If the two countries can work together to shore up the buy-in for the target, that will very considerably smooth the way for having it adopted," said Lauri Myllyvirta, the lead analyst at the Centre for Research on Energy and Clean Air.

The U.S. and China agreed to restart talks on energy policies and launch a working group on enhancing climate action in what they called "the critical decade of the 2020s." Experts say the world needs to act now to have any chance of achieving the agreed-upon goal of limiting the average increase in global temperatures to well below 2 degrees Celsius (3.6 Fahrenheit).

A climate expert described the agreement by both countries to include methane in their next climate action plans as "a major step."

"Methane has been notably absent from China's previous commitment" under the 2015 climate treaty known as the Paris Agreement, said David Waskow, the international climate director at the World Resources Institute. He noted that China is the world's largest emitter of methane and that "serious actions to curb this gas is essential for slowing global warming in the near-term."

The Chinese government issued an action plan last week to control methane emissions, including the development of an accounting and reporting system for emissions. Major emitters include coal mines, oil and gas fields, farms, landfills and sewage treatment plants.

Myllyvirta said the plan is very generic without any measurable emissions targets, so "follow-up on that front will be important."

The U.S. and China also said that together with the United Arab Emirates, they would host a meeting on methane and other greenhouse gases during the upcoming U.N. talks in Dubai.

Waskow expressed disappointment that the joint statement didn't pledge to phase out fossil fuels. That wasn't a surprise — even as China has rapidly expanded in wind and solar power, it has encouraged the construction of coal power plants, which it sees as a more reliable source of power for periods of peak demand.

The government announced last week that it would begin making "capacity payments" next year to coal power plant operators to keep them open and available for use, even as revenues fall as their electricity production is increasingly replaced by renewable energy.

The U.S.-China joint statement welcomed climate cooperation between states, provinces and cities and said the two countries would hold a high-level event on such cooperation in the first half of 2024.

The governor of California, Gavin Newsom, made a weeklong visit to China last month to promote joint climate efforts in several cities and provinces.