From US President Donald Trump's all-out push for fossil fuels to political squabbles in Europe, governments are retreating on their climate promises. But most people around the world still see global warming as a serious threat.

Climate change "will not lead to humanity's demise," billionaire philanthropist Bill Gates has said in a long memo in which he argued that tackling global disease and poverty will help prepare the planet's poorest for a warming world.

The UN estimated Tuesday that nations' carbon-cutting pledges imply a far-from-sufficient 10-percent emissions cut by 2035, cautioning that it was unable to provide a robust global overview after most countries failed to submit their plans on time.