With COP26 in its final days, the world's top two global polluters – China and the US – surprised the summit with a landmark joint declaration on enhancing climate action in the 2020s.

“The United States and China have no shortage of differences,” US special climate envoy John Kerry said when announcing the agreement on Wednesday evening. “But on climate, cooperation is the only way to get this job done.”

The two sides said they intend to cooperate on regulatory frameworks and environmental standards related to reducing emissions of greenhouse gases this decade, while maximising the societal benefits of the clean energy transition.