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September Sea Ice Outlook: July Report

Release Date: 
18 August 2008

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The outlook for the pan-arctic sea ice extent in September 2008, based on July data, indicates a continuation of dramatic arctic sea ice loss. The July Sea Ice Outlook report is based on a synthesis of 22 individual projections utilizing a range of methods. Projections based on July data show no indication that a return to historical sea ice extent will occur this year.

The range of responses was from 3.2 to 5.6 million square kilometers. Of the 22 contributions, 16 gave numerical values for the pan-arctic sea ice extent (see figure below). All estimates are well below the 1979–2007 September climatological mean value of 6.7 million square kilometers.

Formatting revised - 29 September 2008Formatting revised - 29 September 2008

  1. Eight (8) respondents suggest a return toward the long-term trend line of summer sea ice loss (pre-2007 long-term trend of approximately 10% loss per decade),

  2. Six (6) respondents anticipate the 2008 extent to be close to the 2007 record sea ice minimum (i.e., 4.3 million square kilometers); and

  3. Two (2) respondents suggest additional ice loss compared to 2007, which would set a new record minimum.

  4. The remainder of the responses were for regional trends or did not provide a numerical value. All individual responses can be found at the bottom of the full report.

Although July data indicated that the sea ice might be on track for a slight recovery from 2007 (though still well below "normal" climatological conditions), new sea ice data and weather forecasts show that total ice extent in early August declined at about twice the rate of any other time this summer. Also of note is new data showing large regions of low sea ice concentrations within the boundary of sea ice extent at the end of July. These conditions might suggest a faster decline through the rest of the melt season.