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.
Crevasses mar stretching ice on the Pine Island Glacier in Antarctica.
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.
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.
A British Antarctic Survey field camp on Alexander Island, Antarctica.
The late summer sun paints the peaks of Adelaide Island, Antarctica.
Hamish Pritchard of the British Antarctic Survey collects samples from Herschel Heights, Alexander Island, Antarctica.
An iceberg in the Ilulissat Fjord which likely calved from the Jakobshavn Isbrae, Greenland's fastest-moving glacier. Legend has it that this glacier produced the iceberg that sunk the Titanic.
A large iceberg in the foreground with Ilulissat, Greenland in the background.
An iceberg in the Ilulissat Fjord which likely calved from the Jakobshavn Isbrae, west Greenland's fastest-moving glacier.
A view of Ilulissat.
Massive icebergs float in and around Ilulissat Fjord, Greenland.
Icebergs have always calved off of glaciers where they hit the sea, but the rate of calving is accelerating with climate change.
Greenland's rate of ice loss has accelerated to five times what it was in the early 1990s, recent research shows.
An iceberg in the Ilulissat Fjord appears sculpted by wind and water.
An iceberg, likely from Greenland's Jakobshavn Isbrae glacier, floats among sea ice.
Looking east down the Ilulissat fjord, which is fed by the Jakobshavn Isbrae glacier.
The calving face of the Jakobshavn Isbrae Glacier, where the end of the glacier meets the sea and begins to crumble into icebergs.
The Greenland ice sheet terminates along this so-called grounded ice margin near the town of Ilulissat. Here, ice is loss by melting rather than iceberg calving as when glaciers meet the sea.
Sarqardliup Sermia, a glacier in western Greenland.
A seaside view of the calving face of Greenland's Jakobshavn Isbrae glacier.