Chinese climate envoy Liu Zhenmin and White House climate advisor John Podesta met for the first time since the departure of their predecessors, whose unusually close relationship helped bring consensus at last year's COP28 summit in Dubai.

In the two days of talks this week in Washington, the pair looked for ways of "promoting a successful COP29 in Baku, Azerbaijan," the next climate summit which takes place in November, the US State Department said in a statement.

Ahead of the Dubai summit, China promised a broad plan to tackle methane, of which it is the world's largest emitter -- an especially touchy political issue as methane comes mostly from its coal mining.

The two countries said they would co-host an event in Baku, the second of its sort, on reducing methane and other non-carbon greenhouse gases.

"The two sides committed to promote bilateral cooperation and conduct capacity building on deploying abatement technologies," the statement said.

They also agreed to improve monitoring and standards "aiming to achieve significant methane emissions control and reductions in the 2020s."

China, however, has stopped short of signing a global pledge led by the United States and the European Union that aims to reduce global methane emissions by at least 30 percent from 2020 levels by 2030.

Methane is far more potent than carbon dioxide, the most prevalent greenhouse gas, but it spends a briefer time in the atmosphere -- years rather than centuries.

Methane is emitted from the production of oil and natural gas as well as agriculture.

Successive UN climate summits have set a goal of stopping the planet form heating up more than 1.5 degrees Celsius (2.7 Fahrenheit) beyond pre-industrial levels to avoid the worst ravages of climate change, but the planet remains well off track.

The Dubai talks for the first time agreed that the world needs to transition away from fossil fuels.

President Joe Biden's administration has seen climate as an area for cooperation with China despite wide differences and tensions.

Previous climate envoy John Kerry, a former secretary of state, developed a friendship with Xie Zhenhua, the veteran Chinese climate negotiator, with the two holding extended, secluded talks in California to pave the way for COP28.