Scientists found 91 volcanoes under Antarctica. Here’s what they might do
The volcanoes are located in the West Antarctic Rift System, a 2,200-mile valley created by separating tectonic plates.
Watch
Greenland Goes Green: Ice Sheet Melted in Four Days
On July 8, NASA satellite imagery showed about 40 percent of Greenland's top ice layer intact. By July 12, only four days later, 97 percent of the ice had melted. Margaret Warner asks NASA's Thomas Wagner for scientific explanation of…
