Commissioned by finance ministers from nations across Africa, Asia, the Americas and the Pacific, the report says the grouping is bearing an “alarming” cost, despite having contributed the least to climate change and having the poorest ability to respond to ever more disasters.

The vulnerable countries say wealthier ones are not curbing emissions, and are failing to meet a $100bn (£80bn) a year commitment to help developing nations adapt.

Climate negotiators are discussing adaptation funding in the German city of Bonn this week.