Frozen water forms glaciers, ice sheets, sea ice, icebergs, snowpack, ice shelves, and permafrost. This section examines how these bodies develop, move, store freshwater, interact with landscapes, and respond to environmental conditions.
Jakobshavn Glacier can travel nearly the length of an Olympic swimming pool in a day. Near its fastest seaward section, measured velocities have at times approached 50 meters per day. That figure is remarkable, but the glacier’s scientific importance comes from how often the pace has...
The Ross Ice Shelf covers approximately 487,000 square kilometers of the southern Ross Sea, an area comparable to a large European country. Its ice front stretches for hundreds of kilometers, yet that imposing cliff reveals only a small part of the shelf. With an average thickness near 350 meters,...
For several weeks in early 2002, a slab of floating Antarctic ice larger than Rhode Island disintegrated into a moving mosaic of fragments. More than 3,250 square kilometers of the Larsen B Ice Shelf broke apart within about 35 days. By mid-April, the main event had ended, leaving open water,...
Pine Island’s floating ice shelf is the seaward extension of one of West Antarctica’s fastest-changing glaciers. The shelf contributes almost no direct sea-level rise when it melts because it already displaces ocean water. Its greater significance is mechanical: by pressing against its margins and...
The most consequential boundary on Thwaites Glacier is hidden beneath hundreds of meters of Antarctic ice. It is the grounding line, where ice resting on the seabed becomes buoyant and begins to float. As that boundary retreats inland, grounded ice is exposed to ocean influence over a larger area,...
Greenland’s ice sheet gains snow and loses ice every year, but the two sides of that ledger no longer balance. Satellite gravity measurements indicate an average loss of about 264 gigatons per year between 2002 and 2025. That transfer of land ice to the ocean raised global mean sea level by...