U.S. climate envoy John Kerry said it was “imperative that China and the United States make real progress” in the four months before the COP28 global climate talks in Dubai, as he met his counterpart Xie Zhenhua in the Chinese capital on Monday.

He also urged China to partner with the United States to cut methane emissions and reduce the climate impact of coal-fired power, with the two sides aiming to rebuild trust following a suspension in talks last year.

As delegates representing the world’s top two greenhouse gas emitters gathered in a conference room overlooking Beijing’s Forbidden City on Monday morning, Xie said the two climate envoys could play a role in improving U.S.-China relations.

“In the next three days we hope we can begin taking some big steps that will send a signal to the world about the serious purpose of China and the United States to address a common risk, threat, challenge to all of humanity created by humans themselves,” Kerry said.

Both China and the United States have experienced months of record-breaking heat and extreme weather. On Sunday, readings at one weather station in the far northwestern region of Xinjiang hit an all-time high of 52.2 degrees Celsius (126 Fahrenheit).

This week’s meetings, which will continue until Wednesday, will have no formal schedule but are expected to focus on the abatement of methane and other non-CO2 emissions, as well as the run-up to COP28.

China’s reliance on coal is also likely to be on the agenda. Kerry praised the “incredible job” China has been doing in building up renewable energy capacity but said it had been undercut by the construction of new coal power plants.

China has pledged to start reducing coal consumption, but not until 2026, and new coal power project approvals have accelerated since last year.