Evidence for thinning of the Arctic ice cover north of Greenland

An ice profiling experiment carried out in the Arctic Ocean in May 1987 provides evidence of a significant decrease in mean ice thickness over a zone extending more than 400 km to the north of Greenland compared to that found in a study made in 1976. This thinning amounts to a loss of volume of at least 15 percent over an area of 300,000 sq km. The nature of the ice thickness distributions suggests that the thinning is primarily associated with the presence of a larger fraction of young 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 interannual variability.