Large iceberg breaks off Pine Island, Antarctica

Science Daily: A large iceberg has just broken off from Pine Island Glacier in Antarctica. Several different processes can cause an iceberg to form, or ‘calve’, such as action from winds and waves, the ice shelf grows too large to support part of itself or a collision with an older iceberg. Since Pine Island Glacier was already floating before it calved, it will not cause any rise in the world sea level.

Iceberg calving like this occurs in Antarctica each year and is part of the natural lifecycle of the ice sheet. A 34-year long study of the glacier has shown that a large iceberg breaks off roughly every 5-10 years. The last event was in 2001.

Pine Island – the largest glacier in the West Antarctic Ice Sheet (WAIS) – is of great interest to scientists because it transports ice from the deep interior of the WAIS to the ocean and its flow rate has accelerated over the past 15 years.

The Pine Island Glacier is up to 2500 m thick with a bedrock over 1500 m below sea level and comprises 10 percent of the WAIS. According to a study by scientists at the British Antarctic Survey (BAS) and University College London (UCL) using ESA's ERS satellite data, a loss of 31-cubic km of ice from the WAIS’s interior from 1992 to 2001 was pinpointed to the Pine Island Glacier.

The thinning caused the glacier to retreat by over 5 km inland, supporting the argument that small changes at the coast of the Antarctic continent - such as the effects of global warning - may be transmitted rapidly inland leading to an acceleration of sea level rise.