United States climate envoy John Podesta said on Friday that plans were moving forward for a summit with China on reducing emissions of methane and other highly polluting non-CO2 gases.
China is the world's leading emitter of climate change-inducing greenhouse gases, including methane, followed by the United States.
Podesta's visit to Beijing comes as experts say China could be near or already at peak emissions -- a potentially watershed moment in international efforts to keep global temperatures below targets set by the 2016 Paris Agreement.
While acknowledging "some differences", Podesta said he had held "excellent" talks with Chinese counterpart Liu Zhenmin and foreign minister Wang Yi in Beijing.
The two sides had "made plans to hold a summit on non-CO2 gas -- methane, N2O, hydrofluorocarbons", he said.
"They get less attention but they're fully half of what's causing global warming," he said.
Wang said on Friday the talks in Beijing had gone "smoothly", hailing "pragmatic results in cooperation".
"Both sides engaged in further dialogue and clarified the direction of our joint efforts," Wang said.
This sends "a positive signal to the outside world that as two major powers, China and the United States not only need to cooperate but can indeed work together", he said.
Climate talks often revolve around reducing the most dangerous greenhouse gas, CO2.
But methane -- which is particularly potent but relatively short-lived -- is a key target for countries wanting to slash emissions quickly and slow climate change.
That is because large amounts of methane simply leak into the atmosphere from oil and gas projects.
Methane emissions from the fossil fuel industry have risen for three consecutive years, according to the International Energy Agency, hitting near-record highs in 2023.
The United States has expressed intentions to hold a summit with China on these types of gases at the upcoming United Nations COP29 climate summit hosted by Azerbaijan in November.
China has stopped short of signing a global pledge led by the United States and the European Union to reduce global methane emissions by at least 30 percent from 2020 levels by 2030.
Previous US 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 ahead of last year's COP28 in Dubai.
Their unusually close relationship helped bring consensus at that summit.
Before the Dubai meeting, China promised a broad plan to tackle methane -- an especially touchy political issue because methane comes mostly from its coal mining.