China, US pledge climate cooperation ahead of Xi-Biden meet

China and the United States pledged Wednesday to work more closely together to fight global warming, declaring the climate crisis "one of the greatest challenges of our time".

The announcement came hours ahead of a summit between presidents Joe Biden and Xi Jinping in San Francisco, further fuelling hopes the two nations can mend relations following years of turmoil over issues including trade, human rights and the future of Taiwan.

In a joint statement following climate talks in the United States, they pledged to make a success of a crucial UN climate summit starting at the end of this month in Dubai.

And they re-committed to the 2015 Paris climate accord goals of holding global warming to "well below" 2C, while pursuing efforts to limit the increase to 1.5C.

"The United States and China recognize that the climate crisis has increasingly affected countries around the world," the statement said.

"They will work together... to rise up to one of the greatest challenges of our time for present and future generations of humankind."

US and Chinese climate envoys John Kerry and Xie Zhenhua met this month at the Sunnylands resort in California in a bid to restart stalled cooperation.

Experts agree that keeping the Paris goals in reach will require an enormous collective effort to slash greenhouse gas emissions this decade.

But that goal is seen as even more challenging in a world roiled by geopolitical storms, including China-United States rivalry.

The International Energy Agency (IEA) warned last month that "immediate reductions" in methane emissions were needed to limit climate warming.

A broad plan by Beijing last week to control its emissions of the gas offered no specific target for reducing them....