loss of Ice

The loss of ice shelves from the Antarctic Peninsula

Floating ice shelves fringe much of the Antarctic ice sheet (only a few small ice shelves exist in the Arctic). Recently considerable research has looked at what controls their size. It is now clear that while the calving of icebergs as large as small countries (e.g., from the Ronne-Filchner and Ross ice shelves in the 1980's and 1990's) may be part of the normal life-cycle of an ice shelf, the progressive retreat of smaller ice shelves on the Antarctic Peninsula may well be linked to the changing climate.

The extent of ice shelves around the Antarctic Peninsula has been catalogued using various data: reports from expeditions, aerial photographs and satellite images. Around 8000 km2 has been lost since the 1950's. In the same period meteorological stations measured an increase in the air temperature of about 2°C. The two observations can be linked, because there exists a climatic limit of viability for ice shelves related to summer temperatures. Warming has pushed the limit south and all the ice shelves that are now outside it have retreated, including Wordie Ice Shelf, the ice shelf that occupied Prince Gustav Channel, and Larsen Ice Shelf A. The final stages of the loss of Larsen Ice Shelf A in 1995 were particularly spectacular; in fifty days an area of ice shelf the size of Surrey broke up into thousands of football pitch-sized icebergs and floated away.

What caused the warming which attacked the ice shelves is not yet clear. It is possible the climate in this region is subject to natural cycles or that the warming could be related to global climate change. If the warming continues more ice shelves may be threatened.