Afkalving

Afkalving, or calving, is the process by which chunks of ice detach from the edge of a glacier or ice shelf and become free-floating icebergs in a body of water. It is a central mechanism in glacier dynamics and mass balance, influencing how much ice a glacier loses each year.

The process is driven by a combination of internal stress within the ice, buoyancy forces on floating sections, and external factors such as ocean temperature and tides. Crevasses and preexisting fractures can grow until a piece becomes large enough to detach. Warmer ocean waters, undercutting by waves, and thinning ice shelves can accelerate calving by weakening the ice margin and increasing instability.

Calving has several important consequences. For land-terminating glaciers, calving contributes to mass loss and, when the calved material reaches the sea, to sea level rise. For floating ice shelves, calving can remove stabilizing extensions and may allow faster ice flow from the land behind the shelf, potentially increasing glacier discharge. The icebergs produced pose navigational hazards and influence marine ecosystems through physical and chemical change in the water.

Monitoring and research methods include satellite imagery, radar, and aerial surveys to track calving fronts, along with measurements of calving rate and iceberg production. Notable calving events, such as large ice losses from Jakobshavn Isbræ and the Larsen B collapse, have highlighted the connection between calving, glacier dynamics, and climate variability.

Afkalving is a widely studied phenomenon in glaciology and climate science, with implications for sea level rise and regional oceanography. See also glacier calving, ice shelf, iceberg, and sea level rise.