The Arctic Perennial Sea Ice Could Be Gone By End of the Century

These two images show Arctic sea ice extent from January 1, 1990 and January 1, 1999, respectively. These images were created using data from the Defense Meteorlogical Satellite Program's (DMSP) Special Scanning Microwave Imager (SSM/I). Credit: NASA

A NASA study finds that perennial sea ice in the Arctic is melting faster than previously thought-at a rate of 9 percent per decade. If these melting rates continue for a few more decades, the perennial sea ice will likely disappear entirely within this century, due to rising temperatures and interactions between ice, ocean and the atmosphere that accelerate the melting process.

Perennial sea ice floats in the polar oceans and remains at the end of the summer, when the ice cover is at its minimum and seasonal sea ice has melted. This year-round ice averages about 3 meters (9.8 feet) in depth, but can be as thick as 7 meters (23 feet).

The study also finds that temperatures in the Arctic are increasing at the rate of 1.2 degrees Celsius (2.2 Fahrenheit) per decade.

Melting sea ice would not affect sea levels, but it could profoundly impact summer shipping lanes, plankton blooms, ocean circulation systems and global climate.

"If the perennial ice cover, which consists mainly of thick multi-year ice floes, disappears, the entire Arctic Ocean climate and ecology would become very different," said Josefino Comiso, a researcher at Goddard who authored the study.

For more on the melting rate of the perennial sea ice, go to: http://www.gsfc.nasa.gov/topstory/2002/1122seaice.html