The midnight sun glows off an iceberg in Disko Bay, Greenland. Icebergs calving into the sea are a major source of Greenland's ice loss.
A stream of meltwater flows across the ice surface in Greenland.
Meltwater creates a 60-foot deep (18.2 meter) canyon in the polar ice sheet.
This canyon drained a large meltwater lake on the surface of the ice into a moulin, or under-ice channel that flows to the bottom of the ice sheet.
Supraglacial lakes like this one (which is about 0.75 miles in diameter) dot the surface of the Greenland ice sheet during the summer seasonal melt.
A moulin dips into the ice sheet, channeling water to the base of the ice, where a network of underground springs route it to the sea.
Pine Island Glacier
Crevasses mar stretching ice on the Pine Island Glacier in Antarctica.
Pine Island Glacier Flow
Crevasses reveal the slow movement of the Pine Island Glacier in Antarctica.
Criss-Crossing Crevasses near the grounding line of the Pine Island Glacier, where the glacier meets Antarctica's sea ice.
Aerial Glacier View
An aerial view of the Pine Island Glacier in Antarctica, looking seaward.
The Staccato Peaks of Alexander Island on the Antarctic Peninsula. Complex weather and snowfall in this region makes assessing ice loss and gain difficult.