U.S. climate envoy John Kerry said more work was needed this year to reach agreements with China on major climate issues, after three days of talks in Beijing to rebuild trust between the world's two biggest carbon polluters.

The two sides agreed climate change was urgent and that they should stick to the global commitment "to keep 1.5 alive,” Kerry said, referring to pledges to keep global temperatures from rising beyond 1.5 degrees Celsius above preindustrial temperatures. That would mark a shift in China's tone, after Chinese officials in previous months appeared to question the latest United Nations scientific report on global warming.

The U.S.-China climate talks had been suspended nearly a year ago after a visit by then-U.S. House Speaker Nancy Pelosi to Taiwan, an island over which China claims sovereignty.