Everyone I spoke to in Australia understood that preserving the Great Barrier Reef in all its greatness was beyond what could realistically—or unrealistically—be hoped for. Even settling for a tenth of it would mean shading and robotically seeding an area the size of Switzerland. What was at issue was, at best, a diminished thing—a kind of Okay

“It depends on human choices about how we use it. So whenever anybody makes a statement that solar geoengineering will imperil millions or save the world or whatever, you should always ask, ‘What solar geoengineering? Done what way?’ ”

It’s often observed that nature—or at least the concept of it—is tangled up in culture. Until there was something that could be set against it—technology, art, consciousness—there was only “nature,” and so no real use for the category.

“We are as gods, but we have failed to get good at it…We are Loki, killing the beautiful for fun. We are Saturn, devouring our children.”

A Mississippi that’s been harnessed, straightened, regularized, and shackled can still exert a godlike force; it’s no longer exactly a river, though. It’s hard to say who occupies Mount Olympus these days, if anyone.

In its broad outlines, Dansgaard’s reading of the Camp Century core confirmed what was already known about climate history. The most recent ice age, known in the United States as the Wisconsin, began roughly a hundred and ten thousand years ago. During the Wisconsin, ice sheets spread over the northern hemisphere until they covered Scandinavia,

This has been a book about people trying to solve problems created by people trying to solve problems. In the course of reporting it, I spoke to engineers and genetic engineers, biologists and microbiologists, atmospheric scientists and atmospheric entrepreneurs. Without exception, they were enthusiastic about their work. But, as a rule, this

the ice sheet’s surface. That summer—a record-breaker—Greenland shed almost six hundred billion tons of ice, producing enough water to fill a pool the size of California to a depth of four feet.

“The current Arctic is experiencing rates of warming comparable to abrupt changes, or D–O events, recorded in Greenland ice cores,” a team of Danish and Norwegian scientists recently reported. Since the melt process is self-reinforcing—water is dark and absorbs sunlight, while ice is light-colored and reflects it—there’s widespread concern that