EVIDENCE FOR THINNING OF THE ARCTIC ICE COVER NORTH OF GREENLAND

IN May 1987 a British submarine carried out an ice profiling experiment in the Arctic Ocean in which the route closely approximated that of an earlier voyage in October 1976. Over a zone extending more than 400 km to the north of Greenland there is evidence of a significant decrease in mean ice thickness in 1987 relative to that found in 1976. This thinning amounts to a loss of volume of at least 15% over an area of 300,000 km2. The nature of the ice thickness distributions suggests that the thinning is primarily associated with the presence of a larger fraction of young and first-year ice, a consequence of wind-driven divergence in the ice cover during the months preceding the 1987 observations. Such a large fluctuation in a region previously believed to possess consistently high ice thicknesses illustrates the importance of monitoring Arctic ice thickness more systematically to determine whether such fluctuations fall within the limits of normal inter-annual variability. © 1990 Nature Publishing Group.