China and the United States have vowed to work together to accelerate climate action this decade, in a surprise new pact in the face of global warming that is already wreaking disasters across the world.
The announcement on Wednesday came as the crunch COP26 summit in Glasgow entered its pivotal final days, with negotiators wrestling over ways to limit global warming to 1.5-2 degrees Celsius from pre-industrial levels.
"This document contains strong statements about the alarming science, the emissions gap, and the urgent need to accelerate action to close that gap," US special envoy John Kerry told reporters in a surprise announcement.
"It commits to a series of important actions now this decade when it is needed."
The plan is light on concrete targets but heavy on political symbolism at a conference that began with the US and China - the world's two biggest emitters - seemingly at loggerheads.
Last week US President Joe Biden criticised the decision of China's President Xi Jinping not to attend the Glasgow summit, saying China "walked away".
China hit back at the time, but ties appear to have thawed ahead of long-awaited bilateral talks next week.
On Wednesday both US and China envoys stressed their countries' collaboration, saying they had agreed to put other differences aside to work on climate.
"Both sides recognise that there is a gap between the current effort and the Paris Agreement goals so we will jointly strengthen climate action," Beijing's longtime climate envoy Xie Zhenhua said.
'Seriousness and urgency'
A document outlining the agreement includes a focus on lowering methane emissions, which Mr Kerry described as the "single fastest and most effective way to limit warming".
It says the two sides will meet regularly to "address the climate crisis".
The document also stresses the need to boost emissions efforts in the short term, with scientists warning that emissions efforts before 2030 are crucial for halting catastrophic global warming.
The declaration said both countries "recognise the seriousness and urgency of the climate crisis".
"They are committed to tackling it through their respective accelerated actions in the critical decade of the 2020s," the document said.
China and US are the two largest emitters in the world and together account for nearly 40 per cent of all carbon pollution.
The US has already said it plans to be carbon neutral by 2050, while China announced its intention last month to reach net-zero emissions before 2060.
The 2015 Paris climate accord commits nations to work towards limiting global temperature rises to between 1.5C and 2C through sweeping emissions cuts.
The United Nations said that all countries' emissions-cutting plans, taken together, were currently set to warm Earth 2.7C by 2100.
UN chief Antonio Guterres welcomed the US-China pact.
"Tackling the climate crisis requires international collaboration and solidarity, and this is an important step in the right direction," he said on Twitter.