The state of polar sea ice in late January 2010 is bad compared to climatological conditions (1979-2000). For the fifth time in the past six years, the global sea ice extent minimum has fallen well below climatological values, as this graph demonstrates. The most recent data show that global sea ice covers ~15 million sq. km., compared to 16 million sq. km. normally. The last two times the annual minimum didn’t fall below climatological norms were in 2008 and 2004. In a nutshell, the annual minimum extent has shifted in behavior in a significant way in the last decade.
The state of Arctic sea ice in January 2010 continues to be poor relative to climatological norms. The areal extent of Arctic sea ice has been below -2 standard deviations since late June 2009. In the two-plus years I’ve been writing about this topic, the areal extent hasn’t exceeded the climatological average. That disturbing trend doesn’t appear likely to change any time soon. Conditions in January continued to be strongly influenced by the strongest negative phase of the Arctic Oscillation in 30+ years. Those conditions can be described as much higher surface pressures than normal, accompanied by much, much warmer surface temperatures than normal – up to 14F warmer than usual. That same phenomenon kept cold Arctic air flowing south over Canada, the U.S. and northern Europe and Russia. For the second time since the fall minimum extent, the 2009-10 sea ice extent has fallen below the 2006-07 extent, as I’ll show below. In the past week or so, Arctic weather conditions have stalled areal ice growth. Unfortunately, there isn’t up-to-date information regarding ice volume. That could be growing while the area is not. In the interest of the minimum ice extent this fall, I certainly hope that’s the case.
The state of Antarctic sea ice in January 2010 is about average relative to climatological norms, but had real differences since December. The areal extent of Antarctic sea ice shifted from near the +2 standard deviation to average, and recently just above average. The cause of this shift was increased melt rates around the continent. The areal extent since November was less than the previous austral summer, when areal extent was at or above the +2 standard deviation value until mid-January 2010. The southern hemispheric melt season should last another month or so before refreezing begins.
Here is a satellite representation of Arctic sea ice conditions from yesterday:
For comparison purposes, here is the similar picture from August:
Here is the time series graph of Arctic sea ice extent with the +/- 2 standard deviations as a light-gray envelope around the climatological average through yesterday:
You can find the NSIDC’s January report here. The page is dynamic, so if you’re reading this after early February 2010, that month’s report will show up first. You can look for the January report on the top pull-down tab on the right-hand side of the page. The January report noted that December 2009 had the fourth-lowest average ice extent for the month since 1978. Ice extent has declined since then at a rate of 3.3% per decade (Figure 3). Recent research indicated that region of the Beaufort and Chukchi Seas were covered with rotten ice floes at the end of the 2009 melt season. That’s not good news for the health of the ice in 2010. The report also mentioned that the Northern Sea Route opened in October 2009, after the fall refreeze had started.
Here is a satellite representation of Antarctic sea ice conditions from yesterday:
Here is the time series graph of Antarctic sea ice extent with the +/- 2 standard deviations through yesterday:
The freeze season in the Arctic will end in about six weeks or so. The melt season in the Antarctic will end in about four weeks. Somewhere in between those two, the minimum global sea ice extent will be reached. The current value is in the top-five lowest extents on record. Will it break the top three? Stay tuned.
Cross-posted at SquareState.