Climate envoys John Kerry and Xie Zhenhua, meeting in Sunnylands, California, from Nov. 4-8, agreed to revive a bilateral climate working group that will discuss areas of cooperation, the joint statement said, though differences remain on issues like phasing out fossil fuels.
"The Sunnylands statement is a timely effort of aligning the United States and China ahead of COP28," said Li Shuo, incoming director of the China Climate Hub at the Asia Society.
Li described the relationship between the world's two biggest greenhouse gas emitters as "a precondition for meaningful global progress" and said the Sunnylands agreement would help "stabilise the politics" ahead of the Dubai talks.
The re-launch of the working group marks the normalisation of the climate relationship between the two countries following a hiatus triggered in 2022 by the visit of former House of Representatives speaker Nancy Pelosi to Taiwan, a self-governing island that China claims as its own.
Partnership between the world's two biggest emitting countries is seen as a crucial element to securing a consensus agreement at COP28.
For the first time, China - the world's biggest emitter of greenhouse gas emissions - will include non-carbon dioxide greenhouse gases like nitrogen oxide in its 2035 national climate plan as well as specific actions to curb methane emissions, major sources of global emissions.
"This implies that China needs to do a lot more to be in line with ambitious global goals," said Joanna Lewis, a professor at Georgetown University's School of Foreign Service.
It also focuses on key areas of cooperation, including abating methane and boosting efficiency and the "circular economy", and exchanging information on policies and technologies to reduce emissions. The two sides also promised to work together to curb forest loss and plastic pollution.
"WORK CUT OUT"
China's efforts to cut its own carbon emissions will be in sharp focus at COP28, with the country still approving new coal-fired power plants in a bid to ensure energy security.
The United States and China said they support a declaration by G20 leaders to triple global renewable energy capacity by 2030, and also agreed to "accelerate the substitution for coal, oil and gas generation," which would result in "meaningful absolute power sector emission reductions" this decade.
That falls short of calling for the phasing out of fossil fuels, a goal that China has described as "unrealistic". However, a report released earlier this week said that record levels of new renewable installations in China may help "all but guarantee" a decline in China's CO2 emissions next year.
Both sides also agreed to include methane in their 2035 climate goals - the first time China has made such a pledge - and committed to advancing "at least five" large-scale cooperation projects in carbon capture, utilisation and storage by the end of the decade.
The joint statement said that the United States, China and COP28 host the United Arab Emirates will hold a Methane and Non-CO2 Greenhouse Gases Summit at COP28.
Li said COP28 still "has its work cut out", particularly on fossil fuels.
"China also needs to consider what further ambition can be brought to COP," he added. "Stopping the approval of new coal power projects is a good next step."