Midnight Iceberg

(Image credit: Ian Joughin)

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.

Meltwater Stream

(Image credit: Ian Joughin)

A stream of meltwater flows across the ice surface in Greenland.

Ice Canyon

(Image credit: Ian Joughin)

Meltwater creates a 60-foot deep (18.2 meter) canyon in the polar ice sheet.

Meltwater Conduit

(Image credit: Ian Joughin)

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.

Glacial Lake

(Image credit: Ian Joughin)

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.

Moulin

(Image credit: Ian Joughin)

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

(Image credit: Ian Joughin)

Crevasses mar stretching ice on the Pine Island Glacier in Antarctica.

Pine Island Glacier Flow

(Image credit: Ian Joughin)

Crevasses reveal the slow movement of the Pine Island Glacier in Antarctica.

Criss-Crossing Crevasses

(Image credit: Ian Joughin)

Criss-Crossing Crevasses near the grounding line of the Pine Island Glacier, where the glacier meets Antarctica's sea ice.

Aerial Glacier View

(Image credit: Ian Joughin)

An aerial view of the Pine Island Glacier in Antarctica, looking seaward.

Staccato Peaks

(Image credit: Ian Joughin)

The Staccato Peaks of Alexander Island on the Antarctic Peninsula. Complex weather and snowfall in this region makes assessing ice loss and gain difficult.