Meet the researchers who are developing new methods for countering global warming using geoengineering. Some solutions come with great risks:
While such tactics could clearly fail, perhaps the greater concern is what might happen if they succeeded in ways nobody had envisioned. Injecting sulfur dioxide, or particles that perform a similar function, would rapidly lower the temperature of the earth, at relatively little expense—most estimates put the cost at less than ten billion dollars a year. But it would do nothing to halt ocean acidification, which threatens to destroy coral reefs and wipe out an enormous number of aquatic species. The risks of reducing the amount of sunlight that reaches the atmosphere on that scale would be as obvious—and immediate—as the benefits. If such a program were suddenly to fall apart, the earth would be subjected to extremely rapid warming, with nothing to stop it. And while such an effort would cool the globe, it might do so in ways that disrupt the behavior of the Asian and African monsoons, which provide the water that billions of people need to drink and to grow their food.