Greenland’s ice cap is now melting at a rate ominously described as “nonlinear”—that is, out of phase with any known precedent, pattern, or cycle. Over the past three decades, the average temperature there has increased by 5°F, with summer temperatures soaring 40°F above normal. During this same period, the rate of melting has increased by a more than a third. “What seems clear now,” wrote Jon Gertner, historian and author of The Ice at the End of the World, “is that Greenland is no longer changing in geological time. It is changing in human time.”
