The state of the Arctic ice in December 2009 is the 2nd worst of any December in recorded history. As has been the case for months now, the areal extent of Arctic sea ice continues to be nowhere near the climatological average. As I’ve stated before, that’s indicative that a new phase of the Arctic (and Antarctic) has been reached. Arctic ice through the month of November mimicked the behavior seen in 2007, the year the extent reached the record low. Slower ice growth was seen in the first half of the month; faster growth was seen in the second half of the month. Not everything is abnormal. Ice growth has been observed in the expected locations for the most part. There is always variability of where the ice grows and when it grows there from year to year. What hasn’t changed too much since 2007 is the lack of long-term (2-year or older) ice, which resists melting in the summer. A key point many climate change deniers miss is that the ice will appear winter after winter for many years to come. The lack of ice in the summer is the issue: increased solar radiation absorption by dark ocean water (instead of being reflected by white ice) adds to global ocean heat content instead of preventing it. Warmer oceans mean higher sea levels and shifting weather patterns – one aspect of climate change.
For comparison purposes, here is the similar picture from August:
Here is the time series graph with the +/- 2 standard deviations through yesterday:
The NSIDC hasn’t issued their early-month report on the Arctic yet. When they do, I’ll provide a link to it and share anything I find interesting from it. Absent that report, I want to share something else I keep me eye on. The University of Illinois’ Polar Research Group maintains a number of maps and plots for both poles of the cryosphere. Additionally, they track the state of sea ice globally through time. As of today, the maximum global extent of sea ice already occurred a couple of months ago and measured ~21 million sq. km. According to the time series, this is near a record low maximum for the year. The only other times this value was reached was in 2001 and 2007 (the record extends back to 1979). The climatological maximum is over 22 million sq. km. The difference might seem small – 1 million sq. km. – but it’s not. Egypt has 1 million sq. km. of land area. So this year, an area of ice the size of Egypt didn’t form. Of more concern is the low anomalies seen the past three years globally: between 2 and 3 million sq. km. or 2-3 Egypt’s worth of ice. That’s what I’m talking about when I say a new phase of the poles has been reached.
This larger view is probably something I’ll put more focus on in the future, hence the updated title from my ongoing series on this subject. Examining the Antarctic is and will be just as important as examining the Arctic.
Cross-posted at SquareState.