China and the US have agreed to boost climate co-operation over the next decade, in a surprise announcement at the COP26 climate summit in Glasgow.

The world’s two biggest CO2 emitters pledged to act in a joint declaration.

It says both sides will “recall their firm commitment to work together” to achieve the 1.5C temperature goal set out in the 2015 Paris Agreement.

They called for stepped-up efforts to close the “significant gap” that remains to achieve that target.

Scientists say that limiting global temperature rises to 1.5C will help humanity avoid the worst climate impacts. This is compared to pre-industrial temperatures.

At Paris in 2015, world leaders pledged to try to keep the world from warming by more than between 1.5C to 2C through sweeping emissions cuts.

China’s top climate negotiator Xie Zhenhua told reporters that on climate change “there is more agreement between China and US than divergence”.

US President Joe Biden and his Chinese counterpart Xi Jinping are expected to hold a virtual meeting as early as next week. The two countries are seen as global rivals on a number of issues.

In Wednesday’s rare joint declaration, there were steps agreed on a range of issues including methane emissions, the transition to clean energy, and de-carbonisation.

But China refused to join an agreement earlier this week to limit methane – a harmful greenhouse gas. The agreement was signed by nearly 100 other countries. China has instead pledged to develop a “national plan” to address methane.

China’s chief climate negotiator Xie Zhenhua said the US and China had held more than 30 virtual meetings

Mr Xie was followed by John Kerry, the US climate envoy, who said the US and China “have no shortage of differences, but on climate, co-operation is the only way to get this job done”.

“Every step matters right now and we have a long journey ahead of us,” he said.