For coastal communities threatened by global warming, the challenge can be sketched with two questions: How much will the waters surge and where will the inundation be worst?
More mysterious is how rising temperatures will impact people inland. Two new papers look at climate change far from the sea and project it could radically alter global politics by the middle of the century.
In the first, Dimitri Defrance, a climate scientist at the Université Paris-Saclay, in France, looks at recent data on the melting of the Greenland ice sheet. Comparing these with data on the melt at the end of the last ice age, they project how the increasing flow of freshwater into the North Atlantic will negatively affect rainfall patterns in the Sahel, a vast and fertile region of Africa between the great deserts of the north and the jungles lining the Equator.
They consider, too, how the Sahel’s population is expected to balloon and how the region’s staple crops — such as sorghum and millet — depend on predictable monsoons.