Every summer, Greenland's ice sheet melts when temperatures warm up. This year, however, saw the start of the ice melt season begin in April, much earlier than normal. 

Global sea ice thumbnail

NASA ice expert Claire Parkinson does the math on global sea ice and confirms that small gains around Antarctica do not cancel out large losses in the Arctic.

(animation) Decades ago, the majority of the Arctic's winter ice pack was made up of thick, perennial ice. Today, very old ice is extremely rare.

Pages