The boiling point of water is straightforward, but the boiling point of societies is mysterious.

Scientists are still trying to puzzle out what caused the wild temperature swings first glimpsed in the Camp Century core. One hypothesis is that they are related to a loss of sea ice in the Arctic, which is worrisome, given that global warming is causing a loss of sea ice in the Arctic. But even putting aside the possibility of a human-induced D–O

It had been known since the third century BCE, when Eratosthenes, the director of the Great Library of Alexandria, measured it using a brilliant theoretical and observational technique.

One year after its founding, L’Isle de la Nouvelle Orléans suffered its first inundation. “The site is drowned under half a foot of water,” Bienville wrote. The settlement would remain submerged for six months. Rather than retreat again, the French dug in. They raised artificial levees atop the natural ones and started cutting drainage channels thr