Fifty Degrees Below

When the storm got bad, Frank Vanderwal was in his office at the National Science Foundation. When it was over, large chunks of San Diego had eroded into the sea, and D.C. was underwater. Everything Frank and his colleagues feared had culminated in this disaster. And now the world was looking to them to fix it.

But even as D.C. bails itself out, a more extreme climate change looms. The melting polar ice caps are shutting down the warm Gulf Stream waters—meaning Ice Age conditions could return. And the last time that happened, eleven thousand years ago, it took just three years to start.…