State of the Arctic (Poles) – 12/30/09

The state of the Arctic sea ice in late December 2009 remains the 2nd worst of any recorded December. The areal extent of sea ice continues to be well below the climatological average, and as it has for most of 2009, significantly below the negative 2nd standard deviation of the 1979-2000 area. The areal extent of Arctic sea ice continues to be anomalously low, as it has for well over a year now. The Hudson Bay has finally iced over. The late freeze this year was due to anomalously warm waters in the Bay in 2009. The Barents Sea remains relatively ice-free for this time of year. Remember, the Arctic Ocean hasn’t seen sun in a couple of months now.

The state of the Antarctic sea ice in late December 2009 is less disturbing. After reaching a high value of ~19 million sq. km. back in late September, the 2009 melt season exceeded that of the 2008 season. That trend shifted slightly as December drew to a close – the areal extent has increased from the 1979-2000 average to the positive 2nd standard deviation. The exact value of areal extent in 2009 remains below the value measured in 2008 by a small amount. The trend found in December is likely due to this year’s storms: both tracks and intensities vary year to year.

Globally, the extent of sea ice in 2009 continued the trend seen throughout the Aught’s: anomalously low extent, as seen in this graph. There were only a handful of times when global ice extent was significantly above the climatological average these past 10 years and none had the magnitude of the record low extents seen in 2007 and 2008. When viewed in the long term, it is clear to see that the state of the poles has shifted in the past 10 years. The majority of that state change has been in the Arctic.

State of the Arctic (and poles) – 12/1/09

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.

Here is my State of the Arctic post for November and for  September.  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 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.

Closing In On Yearly Arctic Ice Maximum – 3/3/09

March is the time of year when the ice in the Arctic reaches its yearly maximum areal extent.  The Vernal Equinox is coming up in a couple of weeks, which means that the Northern Hemisphere is going to start receiving more sunlight than not every day.  The National Snow and Ice Data Center released a news update this morning on this subject.  Here are a few items worthy of examination.

Ice extent averaged for February 2009 is the fourth-lowest February in the satellite record.  February 2005 had the lowest ice extent for the month; February 2006 was the second lowest; and February 2007 is in third place. Including 2009, the downward linear trend in February ice extent over the satellite record stands at –2.8% per decade.

The news release has a times series graph demonstrating this decline.  The site also has an ice extent vs. date graph in which it compares winter 2008-09 extent to the climatological average (1979-2000) and to the 2006-07 data.  2006-07 is used because the record minimum extent occurred in the fall of 2007.  Comparing today’s conditions to the worst ever is a good idea, I think.  I’ve read murmurings from the climate change denialists that things are fine since today’s extent isn’t as bad as the worst case.  That’s like saying today’s economy is fine since it’s not quite as bad as the 1st Republican Great Depression.  It’s a ridiculous statement to make.  The extent of Arctic ice today is nearly 1,000,000 sq. km. below normal (dynamic link – only good for a few days).

The long-term trend is clear and it isn’t good.  The Arctic needs but the right kind of summer weather conditions in order for even more ice to melt this year.  And that’s what’s hidden in the areal extent data: it says nothing about ice volume, which is dangerously low.  The amount of multi-year ice decreased to very low levels last summer/fall.  That makes this year’s ice pack all the easier to melt.

Related to the news release is the state of the Antarctic ice sheet.  It appears to have reached this year’s minimum areal extent of about 2,000,000 sq. km (dynamic link – only good for a few days).  That’s the climatological norm for this time of year, which is quite a different story than what denialists would have the public believe.  According to them, Antarctic glaciers and ice are increasing.  That is devoid of the requisite detail to describe the actual reality.  Compared to this same date last year, there is ~600,000 sq. km. less ice today.  I won’t speculate on whether this is indicative of any kind of trend.  It’s certainly at the long-term average.  My worry last fall was the maximum areal extent reached a near-record low, which was a clear break in a recent trend.  How the ice sheet fares this austral winter remains to be seen, of course.

Recent news of melt rates increasing at both poles is very disconcerting.  Global ice conditions remain in less than healthy shape, as this graph demonstrates.  Last spring saw the only above-average areal ice extent since 2003.  Every other data point since then has been at or well below average.