No company in the United States has ever restarted a reactor that was seemingly closed for good, but there are now three major efforts underway to do so.

© Nick Rohlman/The Gazette, via Associated Press

No company in the United States has ever restarted a reactor that was seemingly closed for good, but there are now three major efforts underway to do so.

Darkened by soot from vehicles and factories, the region’s glaciers are absorbing more heat and melting at dangerous rates.

© Jason Gulley for The New York Times