MercoPress. South Atlantic News Agency

Arctic icecap thinning faster than expected even in

British researchers have found that the Arctic icecap is now shrinking at an unprecedented rate even in winter, a development that could mean that the summer icecap may vanish within a decade.

The study led by Dr Katharine Giles, of the Centre for Polar Observation and Modelling at University College London (UCL), gave substance to the widely reported summer shrinkage earlier this year that resulted in the opening of the Northwest Passage. The research, reported in Geophysical Research Letters, found that the summer shrinkage is continuing in the winter months, with the thickness of sea ice decreasing by a record 19% last winter. "After the summer 2007 record melting, the thickness of the winter ice also nose-dived. What is concerning is that sea ice is not just receding but it is also thinning", Giles was quoted as saying by The Times. Scientists have expressed concern that a possible longer-term change, such as a rise in water temperature or a change in ocean circulation, could mean that the summer icecap could vanish within a decade, the report in the British daily said. Usually the Arctic icecap recedes in summer and then grows back in winter. These findings suggest the period in which the ice renews itself has become much shorter. The loss of average thickness of sea ice over the whole Arctic saw the Northwest Passage become ice-free and open to shipping for the first time in 30 years during the summer of 2007. The UCL researchers used satellites to measure sea-ice thickness from 2002 to 2008. Winter sea ice in the Arctic is about 8ft thick on average. The team is the first to measure ice thickness throughout the winter, from October to March, over more than half of the Arctic, using the European Space Agency's Envisat satellite. Giles's findings confirm the more detailed work of Peter Wadhams, professor of ocean physics at Cambridge University, who has undertaken six voyages under the icecap in Royal Navy nuclear submarines since 1976 and has gathered data from six more voyages.