OUR CHANGING ENVIRONMENT: Pine Glacier, Antarctica

The images above show the break-off of a large iceberg from the Pine Island Glacier in West Antarctica. This event occurred sometime between 4 and 12 November 2001, and provides powerful evidence of rapid changes under way in this area of Antarctica. The iceberg measures about 42 x 17 km.

Pine Island Glacier is the largest discharger of ice in Antarctica and the continent's fastest moving glacier. It is located in an area of the West Antarctic ice sheet that is believed to be the most susceptible to collapse, making the evolution of this glacier of great interest to the scientific community.

In mid-2000, a large crack formed across the glacier, and then began to grow rapidly. Data indicated the crack was growing some 15 metres a day. The images show that the last 10-km segment that was still attached to the ice shelf snapped off in a matter of days.

The first image in this set was captured in late 2000, early in the development of the crack. The second and third views were acquired in November 2001, just before and just after the formation of the new iceberg.

The newly hatched iceberg represents nearly seven years of ice outflow from Pine Island Glacier released to the ocean in a single event. The climatic significance of this calving event is not yet clear. However, when combined with previous measurements from this instrument and data from other instruments cataloguing the retreat of the glacier's grounding line, its accelerating ice flow, and the steady decrease in the sea ice cover in front of the glacier, it provides scientists with additional evidence of rapid change in the region.

Text and imagery: NASA/GSFC/LaRC/JPL, MISR Team