No new ice minimum in the Arctic in 2008

The drifting sea ice in the Arctic is an indicator of climate variability, which is caused both by natural and increased greenhouse gasses by human activities.

Last years record minimum ice area of less than 4 mill km2 compared to the average value of 6 mill. km2 over the 1979-2007 period, lead to speculation by many research groups that the ice cover in the Arctic had reached a tipping point and that it would disappear during the summer at a much earlier time than projected by the Intergovernmental Panel on Climate Change (IPCC) of the United Nations.

Therefore, there has been a lot of interest to follow the development of the Arctic ice cover this year. Several US groups projected a new minimum this year while the Nansen Center in Bergen, in a press release by Reuters (@ blogs.reuters.com/environment/), indicated that a new minimum would not occur.

The ice minimum has now been reached, 11 September 2008, and was 0.1 mill. km2 higher than the 2007 minimum. Both the ice area and in particularly the ice extent (defined as 15% ice concentration) has started to increase implying that the freezing season is beginning. Therefore a new minimum has not occurred in 2008, but still the minimum of 2008 is 4 mill. km2, which is well below the 1979-2007 average.

The reason for the low ice area in 2008 is partially caused by the minimum of 2007, which is also an expression of the multiyear ice for the winter of 2007-2008. Less multiyear ice causes an easier melt of the first year ice in the summer of 2008, in addition to the general trend of increased melt caused by increased greenhouse gases (see CO2/Ice paper by Ola M. Johannessen, available @ ftp://ftp.nersc.no/Press/OLA.pdf).

During the 2008 summer season both the Northwest and Northeast passages were free of ice simultaneously, which probably is the first time in thousands of years. In the not too distant future, both these passages will be new shipping corridors between Europe, North America and Asia, saving roughly 10 days in transit.

The outlook for the future of the Arctic ice cover is grim. The increasing melt during the summer, reaching a blue Arctic probably before 2050, will cause the Arctic to be like Antarctica implying a seasonal ice cover. At present our predictive capability of the ice cover both on seasonal, decadal and longer time scales is poor and needs increased attention immediately. An attempt to monitor and perform short term forecast has been initiated through the project IPY Arctic GOOS coordinated by Ola M. Johannessen and the Arctic ROOS alliance has been created in the framework of EuroGOOS, coordinated by Ola M. Johannessen and Stein Sandven.

For more information contact:
Ola M. Johannessen, tlf +47 901 35 336
For images, mm, contact:
Tor I. Olaussen, tlf. +47 917 369 63

For updated online information:

http://arctic-roos.org/observations