Earth's ice sheets are rapidly losing volume as humans have warmed the Arctic by over 2 degrees Celsius in the past 50 years. Could Greenland really unfreeze? And what might happen if it does?

Mount St. Elias, the third-highest peak in North America, is among the fastest growing ranges in the world, rising 3 to 4 millimeters a year. Find out what this natural laboratory is helping scientists learn about mountain building.