5 January 2011
NOAA/NSIDC: December Arctic Sea Ice Lowest on Record
Posted by Dan Satterfield
The National Snow Ice Data Center (NSIDC) released the Arctic ice summary for December today. It’s the lowest on record at 12 million square km. This is 270,000 sq. km below the previous record.
The highly negative phase of the North Atlantic Oscillation is likely a contributing factor here. The negative NAO has drained much of the polar cold down into two main regions; Eastern N. America and Western Europe. The warmer than normal temps over Greenland, and in extreme East Russia have also slowed ice growth.
Hudson bay is normally totally frozen over by late December. Look at the ice cover chart on the right. It’s still not.
Natural atmospheric and ocean oscillations cause the ice coverage to vary from year to year, but the increasing greenhouse gases are almost certainly responsible for the long term steady decline.
Besides the arctic ice coverage, the thickness of the ice is declining even more precipitously. The Polar Science Center at the Univ. of Washington uses data from many sources to produce a model (called PIOMAS) of the volume of Arctic ice. The volume as of Sept. 2010 was the lowest on record.
The outlook for January seems to be for more of the same; at least for the first 10 days or so. The NAO will remain highly negative for at least the next week or so. It’s looking possible that another major snowstorm is on the way for next week too.
In a few days, you can expect to hear that Jan- December 2010 was either the warmest or second warmest year on record as well. NASA, NOAA and the UK Met Office (Hadley Center) all do independent analysis.
The data should be fascinating.
Dan,
With the last graph (on ice volume), what do the gray shaded areas parallel to the blue trend line represent? I’m confused — usually that indicates (to me) the uncertainty, but some of the data lies outside those bounds….
C
The shaded areas are 1-3 standard deviations of the trend. Should have noted that.
For a little context, could you provide the number of years meant by the “…on record.” phrase. (For each of the times that phrase is used, please.)
Considering the limited number of years that trustworthy technology and methods have been in place for such measurements and the fact that some weather patterns/seasons cover time periods lasting from decades to centuries in length, using the phrase “on record” doesn’t carry the same weight in all discussions.
The satellite record of Arctic Sea ice starts in the 1970’s. Proxys are available for longer along with submarine and ship reports. While the arctic ice record is limited, the temperature record for the past 500 years is quite reliable using multiple proxies. This record indicates the Arctic is likely warmer than anytime in the past 1000 years or longer.
As for natural weather patterns. There are indeed natural oscillations in the atmosphere and ocean. The periods range from daily to weekly to decadal. None of these have been able to explain the rise in temperature over the Arctic and the loss of sea ice. Could there be a natural cycle responsible for the loss of ice? Yes, but that would not negate the fact that the rising greenhouse gases also are playing a role. Physics is physics.
Researchers have been looking very hard to find some other reason for the loss but nothing has been found.
Virtually every climate model however does show an amplification of temperature over the Arctic when increasing greenhouse gases are accounted for. When greenhouse gases are held at constant levels the arctic sea ice does not behave as it has been doing.
Nearly every atmospheric physics expert on Arctic sea ice will tell you that it’s in a death spiral due to rising greenhouse gases. The only uncertainty is how fast it will disappear. You can read more from those experts at the web site of the National Snow Ice Data Center.