The records broken this winter were supposed to be for cold weather. But fast on the heels of the Arctic seeing the lowest January sea ice extent in the satellite record, the National Snow and Ice Data Center reports:
February 2011 tied February 2005 for the lowest ice extent for the month in the satellite record. Including 2011, the February trend is now at -3.0 percent per decade.
The NSIDC has more details:
While ice extent has declined less in winter months than in summer, the downward winter trend is clear. The 1979 to 2000 average is 15.64 million square kilometers (6.04 million square miles). From 1979 through 2003, the February extent averaged 15.60 million square kilometers (6.02 million square miles). Every year since 2004 has had a mean February extent below 15 million square kilometers (5.79 million square miles).
You can read some of the underlying conditions in the NSIDC post, including an extensive discussion of the Arctic Oscillation (AO). Here’s a less technical discussion from NSIDC director Mark Serreze:
Mark Serreze, director of Boulder, Colorado’s National Snow and Ice Data Center, said the warming trends under way have had a noticeable impact on the Arctic region this winter. According to UCS, Serreze pointed out that winter temperatures this year have been at near record highs and the area covered by sea ice had shrunk to record low levels in December, January and February.
Serreze noted that less sea ice could lead to other global warming impacts, notably a strong negative phase of the Arctic Oscillation, the atmospheric circulation pattern in polar regions. Higher than normal atmospheric pressure occurs during the negative phase, resulting in wind patterns delivering warmer than average temperatures to the Arctic. In turn, cold Arctic air is forced down to middle latitude in Europe and the US.
“It’s still cutting edge research and there’s no smoking gun, but there’s evidence that with less sea ice, you put a lot of heat from the ocean into the atmosphere, and the circulation of the atmosphere responds to that. We’ve seen a tendency for autumns with low sea ice cover to be followed by a negative Arctic Oscillation,” Serreze said in the UCS release.
And shrinking sea ice is still bad news for humanity:
- Tundra 4 — Permafrost loss linked to Arctic sea ice loss: “We find that simulated western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate-change trends. The accelerated warming signal penetrates up to 1500 km inland”¦.”
- NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100; Study underestimates impacts with conservative assumptions.