In March the Arctic ice cap reaches its greatest annual extent. And this year's March ice cover only a little smaller than it's been it the past.
But look at this: red indicates one-year old seasonal ice.
Mason Inman reports on data from the National Snow and Ice Data Center showing that perennial or multi-year ice has dropped by half since the 80s and early 90s: Shrinking Arctic Sea Ice Thinner, More Vulnerable (National Geographic News, March 18, 2008)
That's important because the seasonal ice is thinner and melts faster. The ice cap is smallest in September and last September it was as small as we've ever seen it. We still don't know what will happen this summer, but the ice cap is starting the season with a big strike against it.
First posted at Ben Muse on March 19, 2008.