WUWT comes in at the median value of 4.6 million square kilometers (they rounded up from our 4.55 submission) . It is important to note that even with the large losses in June, nobody who submitted to ARCUS is forecasting the “ice free arctic” to match Jay Zwally’s outlandish claim of “…the Arctic Ocean could be nearly ice-free at the end of summer by 2012″
See the graph below to take it all in.
From ARCUS: July Sea Ice Outlook.
With 21 responses for the Pan-Arctic Outlook (plus 5 regional Outlook contributions), the July Sea Ice Outlook projects a September 2012 arctic sea extent median value of 4.6 million square kilometers (Figure 1). The consensus is for continued low values of September sea ice extent. Individual responses are based on a range of methods: statistical, numerical models, comparison with previous rates of sea ice loss, composites of several approaches, estimates based on various non-sea ice datasets and trends, and subjective information. Again, it is important to note for context that the estimates are well below the 1979–2007 September mean of 6.7 million square kilometers. The quartiles for July are 4.2 and 4.7 million square kilometers, a rather narrow range given that the uncertainty of individual estimates are on the order of 0.5 million square kilometers. This is also a narrower range than last year, which was 4.0 to 5.5. The July Outlook is generally similar to the June Outlook; the July median is higher by 0.2 million square kilometers than the June estimate, but the quartiles are similar.
Just after the June Outlook was completed (based on May data), arctic sea ice extent briefly set record daily rates of loss.
In June we saw the second-most cumulative loss in the satellite record since 1979, behind the record minimum extent for June in 2010. We also saw cases of early melt in some regions. The culprit for the rapid sea ice loss in early June was again the presence of the Arctic Dipole (AD) pressure pattern, but the pattern shifted towards the end of the month and ice loss slowed.
The Sea Ice Outlook is organized by the Study of Environmental Arctic Change (SEARCH) and the Arctic Research Consortium of the U.S. (ARCUS), with volunteer efforts of Outlook contributors. Funding is provided by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA).
As always, for a complete view of Arctic and Antarctic sea ice data, visit the WUWT Sea Ice Reference Page.