With this week's U.N. climate science report laying bare the staggering economic costs and losses already faced from climate change, an inevitable question arises: Who should pay?

Within U.N. climate negotiations, "loss and damage" refers to the costs countries are incurring from climate-related impacts and disasters — costs that disproportionately hit the world's poor and vulnerable who did least to cause global warming.

Drawing on more than 34,000 references from the latest scientific papers, the report released on Monday by the U.N. Intergovernmental Panel on Climate Change (IPCC) confirmed that economic sectors from agriculture and fishing to tourism were already being damaged.