Ice Caps

The ice sheets

A sheet is bigger than 50,000 km²; anything smaller is an ice cap or a glacier.

• East Antarctic Ice Sheet

  The largest single mass of ice on Earth, up to 4.8 km (2.98 mi) thick and grounded on high bedrock.

  ~21M km³

  ≈ 5.04M mi³

• West Antarctic Ice Sheet

  Marine-based and thinning at its edges, where warm ocean water gets underneath.

  ~3.8M km³

  ≈ 0.91M mi³

• Greenland Ice Sheet

  2.9M km³ (0.7M mi³) of ice losing roughly 250 billion tonnes a year.

  1.71M km²

  ≈ 0.66M mi²

• Ice caps

  Domes smaller than a sheet — Vatnajökull in Iceland, Barnes Ice Cap in Canada, the Patagonian icefields.

Frozen sea and flowing ice

Sea ice floats and refreezes; glaciers are rivers of ice that never stop moving.

• Arctic sea ice

  Shrinks to its September low, roughly 40% smaller than in 1979.

  ~4M km² minimum

  ≈ 1.54M mi²

• Antarctic sea ice

  Peaks each September around a continent that is itself ringed by ice shelves.

  ~18M km² maximum

  ≈ 6.95M mi²

• Mountain glaciers

  Outside the two sheets, they lost about 267 billion tonnes a year between 2000 and 2019.

  ~198,000

• Permafrost

  Ground frozen for two years or more, holding twice the carbon of the entire atmosphere.

  ~23M km²

  ≈ 8.88M mi²

• Ice shelves

  Floating tongues of glacier that slow the ice behind them — when they collapse, the glaciers speed up.

Did you know?

• Antarctica is the world's largest desert: the interior receives less precipitation than the Sahara.
• Fresh snow reflects 80–90% of sunlight, which is why ice helps keep the poles and the whole planet cool.
• The Antarctic ice sheet is so heavy it presses the bedrock below sea level in places.
• Ice core bubbles trap ancient air — the oldest continuous records reach back 800,000 years.

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