Gradual increase, not decrease
The sea ice in the Arctic has been investigated with new measurements and a model, which connects the ice with the ocean and the atmosphere above. Updated satellite pictures measures the drift of sea ice in the Fram strait between Svalbard and Greenland the last 4 years. It shows a gradual increase of 37 % since August 2007. The transportation of heat in the ocean has increased in both the Fram Strait and the Bering Strait between Alaska and Siberia. On the other hand, the atmospheric heat transport has been constant since 1990. Our calculations shows that the transportat of sea-ice in the Fram Strait affects the ice in the Arctic even more than an estimated heat supply from the ocean of 40 Terra Watt. The extra heat in the ocean stays more or less at 200-500 meters depth because the stable water masses of the Arctic Ocean prevent efficient mixing of heat.
Alltime low ice cover in 2007
The ice cover in the Arctic was at a record-low level in September 2007. Today high ice drift out of the Arctic, and warm water transportation in the Arctic, gives possibilities to summers with less ice area in future summers like 2007. Nevertheless, if future high sea-ice transport and the extra oceanic heat decrease, the ice can become thicker and cover a larger area in the future.
Greenhouse gases reduces ice thickness
The increase of greenhouse gases in the atmosphere leads to a gradual increase of long-wave radiation towards the surface, also in the Arctic. This will reduce the sea ice thickness, which was on average 3 meters over the entire Arctic in the 1950s. The ice will never be that thick again, in best case it could increase to approximately 2 meters thick in the years to come. Given that the greenhouse gases in the atmosphere keep increasing like they are now, the Arctic will be 95% open ocean during the summer in 2050. The ice will cover an area of the size of Norway, and will only be a small reminder of the ice cover as it was 100 years ago, when it covered an area the size of Europe.
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