Broecker: It won’t be Greenland melting; it will be difficulty in finding food. If this summer doesn’t turn out to be just a fluke, they’re going to have to start irrigating the corn, and of course that would use up a lot of our water supply, and be very expensive—food prices will go way, way up. Eventually, people will be ready to do something. It won’t happen tomorrow, I won’t be around to see it (Broecker is 80 years old) but maybe in ten or twenty years. These will be interesting times.
If not air capture, then injecting sulfur dioxide into the stratosphere might be tried (to reflect sunlight and cool the atmosphere), but that is a very risky experiment. And of course, it wouldn’t be uniform around the globe, so it would be very, very difficult to control. Very messy.