The media are atwitter because the National Snow & Ice Data Center (NSIDC) announced that: “Arctic sea ice appears to have broken the 2007 record daily extent and is now the lowest in the satellite era….Arctic sea ice extent fell to 4.10 million square kilometers (1.58 million square miles) on August 26, 2012. This was 70,000 square kilometers (27,000 square miles) below the September 18, 2007 daily extent of 4.17 million square kilometers (1.61 million square miles).”
If that is true, then the world has 0.006% less ice this year than in 2007. (Source).
The NSIDC would have us believe that the satellite era began in 1979, but it actually began in 1967. Below is a graph from Steve Goddard with data from IPCC 1990 report showing that sea ice was much lower prior to 1979 which happened to be the year of largest sea ice extent since 1967. We should also note that extent of Arctic sea ice is cyclic. Setting records depends on where you start counting.
In an earlier announcement, NSIDC said “Sea ice extent dropped rapidly between August 4 and August 8. While this drop coincided with an intense storm over the central Arctic Ocean, it is unclear if the storm prompted the rapid ice loss.” NSIDC called the storm “The Great Arctic Cyclone of 2012″ and noted the storm caused “mechanical break up of the ice and increased melting by strong winds and wave action during the storm.” Nothing to do with global warming. A similar event happened in 2007 to cause the lower sea ice extent reported then.
Curiously, the NSIDC announcement failed to mention their earlier post and earlier satellites when touting the new “low record.” And it may in fact not be a new record even starting at 1979.
Anthony Watts at WUWT reports that “another NSIDC product, the new and improved “multi-sensor” MASIE product, shows no record low” with sea ice extent at ~ 4.7 million square kilometers which is more than in 2007. “Another product, NOAA’s National Ice Center Interactive Multisensor Snow and Ice Mapping System (IMS) plot, also shows no reason for claiming a record at all. Their number is (for 8/22) ~ 5.1 million square kilometers.” And on NOAA’s National Ice Center, “The numbers they give for 80% and marginal ice add up to an extent of 6,149, 305 square kilometers,” far above the hyped low announced. (The National Ice Center (NIC) is a multi-agency operational center operated by the United States Navy, the National Oceanic and Atmospheric Administration, and the United States Coast Guard.)
To put things in perspective, we have this AP story from the Washington Post:
The Arctic ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the water too hot, according to a report to the Commerce Department yesterday from Consul Ifft, at Bergen, Norway.
Reports from fishermen, seal hunters and explorers, he declared, all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met with as far north as 81 degrees 29 minutes. Soundings to a depth of 3,100 meters showed the gulf stream still very warm.
Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared. Very few seals and no white fish are found in the eastern Arctic, while vast shoals of herring and smelts, which have never before ventured so far north, are being encountered in the old seal fishing grounds.
That story was written in November 2, 1922 (see the more detailed original here).
For some additional perspective, a paper published last year found that 8,000 years ago Arctic sea ice extent was just half of the “record” low of 2007.
To recap, the “record” lows of 2007 and perhaps 2012 were aided by ice transport out of the Arctic by storms. It has nothing to do with alleged anthropogenic global warming.
Another thing rarely mentioned: when the Arctic ice reached a low in 2007, Antarctic sea ice reached the greatest extent ever measured. In 2012, Antarctic sea ice remains above the 1979-2008 mean value.