Antarctica Ice Rapidly Depleting, Say Researchers

The European Space Agency's Envisat satellite has recorded a rapid depletion in Antarctica's ice shelves over the past 10 years. Researchers from the ESA and the University of Innsbruck attribute the rapid fall to global warming.

"Climate models are predicting drastic warming for high latitudes," said Helmut Rott, Professor at the University of Innsbruck.

Researchers had launched one of the satellite's first observations on 1 March 2002. They found a section of the Larsen B ice shelf in Antarctica - when 3,200 sq km of ice disintegrated within a few days due to mechanical instabilities of the ice masses triggered by climate warming.

Now, after ten years of observations, Envisat's Advanced Synthetic Aperture Radar (ASAR) has mapped an additional loss in Larsen B's area of 1,790 sq km over the past decade.

Larsen B decreased in area from 11,512 sq km in early January 1995 to 6,664 sq km in February 2002 due to several calving events. The disintegration in March 2002 left behind only 3,463 sq km. Today, Envisat shows that only 1,670 sq km remain. This clearly shows that more than 80 per cent of ice has decreased over the past few decades.

According to the researchers, the northern Antarctic Peninsula has been subject to atmospheric warming of about 2.5°C over the last 50 years - a much stronger warming trend than on global average, causing retreat and disintegration of ice shelves.

Researchers believe that long-term observations are of particular importance for understanding and modelling cryospheric processes in order to advance the predictive capabilities on the response of snow and ice to climate change

"Ice shelves are sensitive to atmospheric warming and to changes in ocean currents and temperatures," said Prof Rott.

"These observations are very relevant for estimating the future behaviour of the much larger ice masses of West Antarctica if warming spreads further south," he added.

Envisat is one of the largest Earth Observation spacecraft launched in 2002. It carries ten sophisticated optical and radar instruments to provide continuous observation and monitoring of the Earth's land, atmosphere, oceans and ice caps. Envisat data collectively provides a wealth of information on the workings of the earth system, including insights into factors contributing to climate change.