25 June 2010

Multi-Year Sea Ice Thins in the Arctic

Posted by John Freeland

Professor David Barber of the University of Manitoba Center for Earth Observation Science recently spoke at the International Polar Year conference in Oslo. An excerpt from his talk refers to the sea ice cover satellite data produced by the National Snow and Ice Data Center, which describes areal extent only:

“Scientists spend a lot of energy discussing the ‘squiggly line’ generated by satellite data on sea ice extent,” Dr. Barber told the audience, showing a graph from the National Snow and Ice Data Center. “But extent alone does not reflect the real condition of the sea ice. I think we are all looking forward to getting reliable data on thickness from CryoSat. Because what really matters is the condition and thickness of the multiyear ice.”

“We are losing 70 000 square kilometres of sea ice (the size of Lake Superior) every year. That adds up to 2.5 million square kilometres over the last 30 years. The reality is even worse,” continued Dr Barber. “Even though the extent of the sea ice – both the winter maximum and the summer minimum – increased in 2008 and 2009, the amount of multiyear ice continued to decline rapidly.”

Barber’s observations came from over-wintering in the Arctic aboard a research ice-breaker. Expecting to be stopped by thick multi-year ice up to 12-meters thick, the icebreaker cut through ice only a couple inches thick at 13-knots.

The entire talk is available here.