Arctic sea ice is not only shrinking in coverage area; it’s also thinning, according to a report and satellite images jointly released on Monday by NASA and the NASA-supported National Snow and Ice Data Center at the University of Colorado.
The Arctic basin is covered in a thick semipermanent sea ice, which is covered in thin seasonal ice caps that are built up each winter, only to melt away again each summer.
The 2009 Arctic summer-melting season is starting out with a substantial amount of thin seasonal ice and an unusually small amount of the thick sea ice, making it more vulnerable to melting, according to the NSIDC’s report.
“Thin seasonal ice–ice that melts and refreezes every year–makes up about 70 percent of the Arctic sea ice in wintertime, up from 40 (percent) to 50 percent in the 1980s and 1990s. Thicker ice, which survives two or more years, now comprises just 10 percent of wintertime ice cover, down from 30 (percent) to 40 percent,” according to the report from the University of Colorado team led by Charles Fowler.
