Global Warming - Caution!!

June is the time when polar scientists start to scrutinize in earnest how much ice will be left atop the Arctic Ocean after this year’s summer melt season. The National Snow and Ice Data Center in Boulder, Colo., reported this week that ice extent — a measure of total ice-covered area, including some gaps in the ice
— was, at the end of May, close to the lowest ever recorded for that time of year.

Ice extent reaches its nadir each September, at the end of the melt season, and something of a cottage industry has sprung up in recent years to predict the final number. But melting ice is a complicated thing, as discussed in a recent Science News feature story, and many such predictions often end up spectacularly off-base. Last year, for instance, every single team of scientists that hazarded an official guess was quite a bit off.

That’s because weather patterns in the Arctic play a major role in determining how much sea ice vanishes in any given year. A couple of strong winds here, an anomalous cold patch there, and suddenly a season that looked like a disastrous meltdown turns out to be almost average. So the dramatic-looking lows at the end of May are no guarantee that overall ice levels will be a record-breaker this year.

Still, there’s no denying the remarkable overall decline of Arctic ice cover since satellite observations began in 1979. Accordingly, among the many expeditions heading north this summer will be a NASA-sponsored cruise called ICESCAPE, for Impacts of Climate Change on the Ecosystems and Chemistry of the Arctic Pacific Environment. The research will focus primarily on biogeochemistry and ecology in the Beaufort and Chukchi seas north of Alaska.

Scientists will depart on the U.S. Coast Guard icebreakerHealy from the Aleutian islands June 15 for a five-week voyage. Don Perovich, a sea-ice expert on the cruise, told reporters this week that the Healy would send back sea-ice conditions every two hours as it transits north. “Our observations will be directly tied in to people trying to estimate what conditions will be like in September, whether we have a record minimum or not,” he says.

At this point, the best anyone can say about what to expect from the Arctic in 2010 is: Check back in the fall.

Credit: ScienceNews