Arctic “from practical perspective” already ice-free in summer
October 30th, 2009 by Jim JustI would argue that, from a practical perspective, we almost have a seasonally ice-free Arctic now, because multiyear sea ice is the barrier to the use and development of the Arctic.
That’s what David Barber, Canada’s Research Chair in Arctic System Science at the University of Manitoba, reported on returning from an expedition that tried and pretty much failed to find a giant multiyear ice pack that was supposed to be in the Beaufort Sea. Instead he found only hundreds of miles of “rotten ice” – 20-inch thin layers of fresh ice over small chunks of older ice.
An article in RedOrbit quotes Barber:
From a practical perspective, if you want to ship across the pole, you’re concerned about multiyear sea ice. You’re not concerned about this rotten stuff we were doing 13 knots through. It’s easy to navigate through.
The 2009 ice cover was the third-lowest on record, after 2007 and 2008. Joseph Romm has posted this graphic at Climate Progress:
According to Barber, the ice is currently being melted both by rays from the sun as well as from below by the warmer water. Scientists have also been seeing more cyclones, which become stronger as they pick up heat from the warmer water. The cyclones produce waves that break up ice sheets and also dump large amounts of snow, which provides a form of insulation and keeps the ice sheets from thickening.
Many scientists now expect the North Pole to be void of ice during summers by 2030 at the latest.