A common maxim about climate change says that wet places will grow wetter, while dry places will dry more. A recent study by US scientists suggests that, when it comes to effects on humanity, rising dryness will be key.
“We show that although some regions do get wetter, many of those are sparsely populated,” says Megan Lickley of the Massachusetts Institute of Technology (MIT), US. “So from the viewpoint of humanity, ‘wet-get-wetter, dry-get-drier’ doesn’t characterize our human future, which is [actually] heavily dominated by drying.”
By 2100, half the world’s population will live in regions where dryness has risen by at least 5%, Lickley and colleague Susan Solomon showed. Assuming a high, “business as usual” emissions scenario, areas that are technically arid will be home to 700 million more people than today.
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