The Polar Science Center at the University of Washington has updated its calculations of Arctic sea ice volume. As usual, Neven has the best graphs of the PSC’s data at his Arctic Sea Ice Blog, a must-read for cryosphere-junkies.
The PSC recently improved their PIOMAS model, which combines the best observational data with their own analysis. They are publishing their findings in the Journal of Geophysical Research, “Uncertainty in Modeled Arctic Sea Ice Volume”:
… the 2010 September ice volume anomaly did in fact exceed the previous 2007 minimum by a large enough margin to establish a statistically significant new record.
And now that 2010 record is broken — and the melt season isn’t over yet.
Indeed, it is going to be a close race to see if we break the record for sea-ice extent, a two-dimensional metric that the media and others focus on because that data is reported every day by many different sources. If you’re interested in that trend, the National Snow and Ice Data Center released its latest analysis yesterday, “Arctic sea ice near record lows” [see figure below].
Those who know polar ice the best know the “death spiral” continues. Far from seeing the Arctic recovering since 2007, as some claimed, the volume of sea ice dropped by another one third in 3 years, according to the PSC!
In November, Rear Admiral David Titley, the Oceanographer of the Navy, testified that “the volume of ice as of last September has never been lower … in the last several thousand years.” Titley, who is also the Director of Navy’s Task Force Climate Change, said he has told the Chief of Naval Operations that “we expect to see four weeks of basically ice free conditions in the mid to late 2030s.”
Here’s another way to look at the death spiral, via Wipneus:
This “shows a little bit more clearly that the current number actually is right on the projected exponential downward trend (although the minimum probably hasn’t been reached yet),” notes Neven.
Whether the trend will actually turn out to be exponential or not remains to be seen. While human emissions drive the long-term trend — and thinning ice and warming waters ensure “recovery” of the sea ice ain’t gonna happen — ice loss year to year is driven by the Arctic summer weather. That weather was always hard to predict and more so now, since it is likely affected by the sharp loss of sea ice in ways we are only beginning to understand.
I have focused on sea ice volume for the past 5 years, since I was fortunate enough to hear Dr. Wieslaw Maslowski of the Oceanography Department at the Naval Postgraduate School in a 2006 American Meteorological Society seminar. He reported that models suggest the Arctic lost one third of its ice volume from 1997 to 2002. He then made an alarming forecast:
And that was in 2006, so he was talking about the possibility of being ice free in 2016 — before the big drop in sea ice area in 2007.
Looking at volume and thickness helped me avoid the mistake that so many others made in thinking that the sea ice “recovered” after the 2007 minimum in sea ice extent. The scientific literature and actual observations continued to vindicate Maslowski’s projection (see New study supports finding that “the amount of [multi-year] sea ice in the northern hemisphere was the lowest on record in 2009″). See also, NSIDC Director Serreze (9/10): Arctic is “continuing down in a death spiral. Every bit of evidence we have says the ice is thinning.”
Maslowski’s basic prediction for many years now has been for “a (virtually) ice-free fall by 2016 (+/- 3 yrs),” though he is in the process of creating a more sophisticated model that he expects “will improve prediction of sea ice melt,” as he explained to me recently.
Long-time readers may remember that Maslowski’s work on ice volume is one of the main reasons I entered into my big $1000 bet with James Annan, William Connolley, and Brian Schmidt (see “Another big climate bet — Of Ice and Men“). That bet was for a 90% drop in sea ice extent in the summer minimum in any year through 2020 vs. the 1979-2000 average summer minimum using NSIDC data.
So for me to win, the sea extent minimum must drop well below 1 million square kilometers sometime in the next 9 years. I still think is a reasonable bet, but this year Maslowski told me a better bet would be for an 80% drop, since he thinks some sea ice above Greenland and Eastern Canada may survive into the 2020s. But if I lose the bet by several hundred thousand square kilometers that won’t change the fact that the Arctic as it has been for apparently a million years will be all but gone, and those who said we were in a death spiral will be proved correct.
Why is this not a purely academic matter? A 2008 study led by David Lawrence of the National Center for Atmospheric Research (NCAR) concluded (see “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”¦.
In other words, if it continues, the recent trend in sea ice loss may triple overall Arctic warming, causing large emissions in carbon dioxide and methane from the tundra this century (for a review of recent literature on the tundra, see “Science stunner: Vast East Siberian Arctic Shelf methane stores destabilizing and venting“). Indeed, Lawrence himself said, “Our study suggests that, if sea-ice continues to contract rapidly over the next several years, Arctic land warming and permafrost thaw are likely to accelerate.”
NCAR said of the 2008 study:
The decade during which a rapid sea-ice loss event occurs could see autumn temperatures warm by as much as 5 degrees C (9 degrees F) along the Arctic coasts of Russia, Alaska, and Canada.
In short, it is going to get hot up North before it gets even hotter:
The time to act was a long time ago, but now is far, far better than later, just to give the next generation some chance.
- NSIDC bombshell (2/11): Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100:
“The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO2 concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate…. [Our] estimate may be low because it does not account for amplified surface warming due to the PCF itself…. We predict that the PCF will change the arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42-88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration.”
Figure: Carbon emission (in billions of tons of carbon a year) from thawing permafrost.