Arctic Sea Ice

The Arctic Regional Ocean Observing System (ArcticROOS) provide operational monitoring and forecasting services of ocean circulation, water masses, ocean surface conditions, sea ice and biological/chemical constituents in the Arctic Oceans.
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NERSC in Media News

News Story

 By Alister Doyle

OSLO | Thu Aug 23, 2012 12:15pm EDT


(Reuters) - The area of ice in the Arctic Ocean has thawed to a record low, surpassing the previous 2007 minimum in a sign of climate change transforming the region, according to some scientific estimates.

"We reached the minimum ice area today (Thursday). It has never been measured less than right now," Ola Johannessen, founding director of the Nansen Environmental and Remote Sensing Center in Norway, told Reuters.

"It is just below the 2007 minimum."

Arctic sea ice area per 22. August 2012. Source; Nansen Center/ www.arctic-roos.orgArctic sea ice area per 22. August 2012. Source; Nansen Center/

Full story at Reuters.

Based on sea ice data found at

Arctic sea ice area (upper) an ice extent (lower) during the years 2007 to 2012 per 25th August, 2012 as reported at the Nansen Center’s European ice information service.   Source: Nansen Center/ sea ice area (upper) an ice extent (lower) during the years 2007 to 2012 per 25th August, 2012 as reported at the Nansen Center’s European ice information service. Source: Nansen Center/ record minimum sea ice area in the Arctic is observed now in August 2012 and the ice is still melting rapidly. The ice area is recorded to be 3,26 million square kilometres on 26th August (see figure below), while the previous record sea ice area minimum was 3.64 million square kilometres, reported in 2007. Also a record minimum ice extent (i.e. the ice edge position, see lower figure) is observed at 4.64 million square kilometres, which is significantly less than previous minimum (4,73 million km2) reported on 19th September 2007. The observations are based on the information published at the Nansen Center’s European ice information service


The Nansen Centers hovercraft expedition now at 85 degrees North in the Arctic Ocean, has during the last days reported warm weather with temperatures between 6-8 degrees C. This indicates that still significant melting of the Arctic sea ice will occur this summer season.

In general, the summer sea ice has decreased by about 10 percent per decade since 1979, when good quality satellite data became available from the U.S. National Ice Data Center. There are often differences between calculations of sea ice extent publish by the various ice centers even when they are using the same satellite data. The reason for this is that the different formulas are used. This difference can be up to ± 0.3 to 0.5 million square kilometers, see, where a comparison is presented.

In general, the ice cover is decreasing and if CO2 emissions continue the summer ice will gradually disappear. This is shown by global climate models, although with a large spread. Ola M. Johannessen published in 2008 a paper "Decreasing Arctic Sea Ice Mirrors Increasing CO2 on decadal Time Scale" (attached). Here he found a correlation of 0.9 based on annual data between increasing CO2 and decreasing ice extent in the Arctic. A similar analysis for every month of September since 1901 to 2011, where ice generally reaches its minimum (not including 2012), indicates that the summer ice will disappear when CO2 concentration is 500 ppmv. Today it is 400 ppmv CO2 concentration and increases by about 2.5 ppmv per year. If this increase continues in the years ahead, which of course we do not hope, the summer ice will disappear in about 40 years. It should be noted that this is a rough estimate, and second, that it is not taken into account the dominant natural variations, which occur in the Arctic climate system.


For further information contact:

Ola M. Johannessen,

Mobile: +47 9013533

Press release attached.

Attached publication; Ola M. Johannessen (2008): Decreasing Arctic sea ice mirrors the increasing CO2 on decadal time scales. Atmospheric and Oceanic Science Letters, Vol.1, No. 1, November, 2008.

An Arctic Regional Ocean Observing System (Arctic ROOS) has been established by a group of 14 member institutions from nine European countries working actively with ocean observation and modelling systems for the Arctic Ocean and adjacent seas.

It provides access to sea ice and marine information from the Arctic, including daily processing of microwave remote sensing satellite data are used to generate;

  • Maps of sea ice concentration
  • Time series of Arctic sea ice area and extent
  • Statistical inter-annual comparison of the ice area and extent
  • Comparison of results from different retrieval algorithms

Seasonal and long term observations;