Shattered first year sea ice called pancake ice has taken over most of the Arctic ocean this winter after ice volume hit a record minimum last September. The thin, broken ice allows more transfer of ocean heat to the atmosphere in the winter and adsorbs more solar energy in the summer. Moreover, it has stronger interaction with winds, increasing the speed of ice export out of the Arctic through the Fram strait (along the Greenland coast). Inflow of warm, salty, Atlantic ocean water is balancing the cold outflow, further amplifying the Arctic Warming.
Pancake Ice
By NSDIC
Record amounts of melting of Arctic sea ice in the summers of 2007 and 2008 have reduced thick multiyear sea ice to record minimum levels this year.
By NSDIC&CU
Record amounts of thin first year sea ice have been recorded this winter. The thin ice is shattered by wind and waves in to "pancakes" which have very different properties from thick multiyear sheet ice.
New ice can form in several different ways. When water is surrounded by ice packs, as has been common in the Arctic, areas of open water are small and there is little chance for wind to work up vigorous waves. In such calm conditions, ice forms in unbroken sheets called 'nilas'.
But now the Arctic has larger areas of open water, and more waves. "As soon as you introduce swell, you get an entirely different form of ice," says Jeremy Wilkinson of the Scottish Association for Marine Science in Oban, UK. Under these conditions, globs of ice crystals tossed about in the water combine to form first a soupy mixture called 'grease ice', and then 'pancakes' of thin ice a metre or two in diameter.
The pancake ice, which responds to wind and swells far more than sheet ice allows for increased coupling between the Arctic Ocean and the atmosphere. More heat and water vapor are released from the ocean warming the atmosphere and allowing more snow to fall. The pancake ice will adsorb more solar heat in the Arctic spring and summer, warming the water below.
Measurements of multiyear sea ice showed much faster rates of arctic ice export into the Atlantic over the past 10 years than in the previous 20.Watch 40mb sea ice movie here. Natural cycles may explain some of the increased removal of ice, but increased wind and wave stress on thinner ice is also a likely cause of the increasing flux of ice out of the Arctic. On the other hand, the loss of sea ice in the Barents sea may be allowing greater influx of warm Atlantic waters moving into the Arctic from the Norway current.
The pancake ice may be a sign that a tipping point has been crossed. Late summer Arctic sea ice may disappear by the end of the coming decade.
The pancake ice is already changing the ecosystem. The mix of ice and water will disrupt the movements of predators like polar bears and will change the environment below the ice for marine organisms in ways we don't yet understand.
Simple graphs of sea ice area show that sea ice areas look pretty close to normal. However, when you see pictures of the ice you can see that it is anything but normal. The deniers and media apologists have convinced a majority of Americans that the effects of global warming are being overstated.
The evidence shows otherwise.