Arctic Sea ice loss – “it’s the wind” says NASA

A science blogger named Tamino, in a post he made here, challenged me to “explain it or shut up” related to the loss of northern hemisphere Arctic ice this season which he claimed was …” undeniable, that it’s not natural variation” in contrast to the southern hemisphere Antarctic setting a new record for ice extent. While I suspect that sea ice is not his specialty, nor is it mine, I will bring some things to the attention of my readers available from literature.

Just last Monday, NASA was quietly issuing a press release explaining why Arctic sea ice loss was so great this year. (h/t Douglas Hoyt).

From the release: A team led by Son Nghiem of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., studied trends in Arctic perennial ice cover by combining data from NASA’s Quick Scatterometer (QuikScat) satellite with a computing model based on observations of sea ice drift from the International Arctic Buoy Programme. QuikScat can identify and map different classes of sea ice, including older, thicker perennial ice and younger, thinner seasonal ice.

“Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic,” said Son Nghiem of NASA’s Jet Propulsion Laboratory and leader of the study. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

In simpler terms, polar wind patterns changed and blew sea ice further south to warmer waters than it normally would. Sea ice can easily be wind driven.

I wonder if that’s the same mechanism that caused loss of Arctic sea ice in the 1920-30’s?

The Arctic is almost as warm now as it was seventy years ago. Unsurprisingly, Arctic ice has diminished. But, as Polyakov et al.show, the long-term changes are “generally statistically insignificant”. But there’s more ice in Antarctica now. It seems that points more to a natural, cyclical variation on a global scale when one pole diminishes while another gains.

Then there’s area to consider, as commenter Aaron wells writes:

According to Cryosphere Today, normal North Pole ice area at this time is about 5 million km^2, with current amounts amounting to a negative anomaly of about 2 million km^2, for a current total of about 3 million km^2. On the other hand, the South Pole normal area is about 15 million km^2, with current amounts amounting to a positive anomaly of 1 million km^2, for a current total of about 16 million km^2.

Now, it is easy to get alarmed about the North Pole numbers, because they have gotten so close to zero. But the truth is about 2/3rd of total North Pole ice always melts by the end of the northern summer. This summer it got down to about 1/4 of the winter amount.

It is much less alarming if you consider the total between the 2 poles. Using the Cryosphere Today normals and current ice areas, there is normally about 20 million km^2, and currently there is only 19 million km^2. When you realize that the total taken together only represents about a 5% reduction from normal, then it does not seem nearly as alarming.

Arctic = 3 million square kilometers – shrinking, new record low
Antarctic = 16 million square kilometers – growing, new record high

Net change in ice area 5%

Polyakov concludes: A combination of century- and half-a-century-long data records and model integrations leads us to conclude that the natural low-frequency oscillation (LFO) exists and is an important contributor to the recent anomalous environmental conditions in the Arctic. This mode of oscillation is related to fluctuations in the thermohaline circulation in the North Atlantic [Delworth and Mann, 2000]. Comparison of the century-long NAO index time series and half a century time series of the polar region SAT, SLP differences, and wind vorticity index shows the existence of the LFO mode in the latter time series. There is evidence that the LFO has a strong impact on ice and ocean variability. Our results suggest that the decadal AO and multidecadal LFO drive large amplitude natural variability in the Arctic making detection of possible long-term trends induced by greenhouse gas warming most difficult.

LFO Variability

It appears that there is precedence for what we are observing today, and a strong suggestion of a cyclical nature that points to a natural variability mechanism. Plus, the most important thing to note is that we only have satellite measured sea ice data from about 1979.  A 30 year trend isn’t enough to conclude much upon, especially when there is clear evidence of a larger period cycle.

Of course, I don’t expect Tamino will pay any attention to any of this, since he’s made it clear that he’s no longer going to listen to anything “deniers” (as he’s labeled those with contrasting views) have to say. That’s OK, I enjoyed the research.

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21 thoughts on “Arctic Sea ice loss – “it’s the wind” says NASA

  1. The main difference between the NH and the SH is human populations and their impact. Hundreds of millions live north of 50 degree north, while in the SH the population south of 50 degrees is a few thousand.

    The obvious implication is that SH sea ice is reacting to global processes, while the NH sea ice is reacting to local anthropomorphic effects such as particulates.

  2. I am assuming the above graph measures global sea ice coverage since 1950 in millions of sq. mi. from norm.

    If so, I agree it doesn’t seem like all that much of a global emergency.

  3. phillip, your argument does not make sense. are you proposing that humans have altered the arctic winds and sea currents? the earth’s atmosphere is well mixed. this means co2 levels are pretty consistent across the globe. they don’t build up in the north due to population. the greenhouse effect is a global phenomenon. it’s not and cannot be hemispherically specific. now a minor wobble on the earth’s axis or alteration in angle to the sun (malinkovich cycles etc) could certainly achieve the results being observed, but clearly, that is not anthropogenic.

  4. particulates tend to have a cooling effect on surface temperature, no?

    No. Back in the 70’s some scientists, worried about global cooling, even suggested finding a way to blanket the artic region with soot to promote melting. Probably a good thing they didn’t succeed.

  5. People are quick to jump on the sea ice MINIMUMS, but not so quick to mention the sea ice MAXIMUMS.

    Watch the following NASA animation:

    http://svs.gsfc.nasa.gov/vis/a000000/a003300/a003370/SeaIceMaxWdates320x240.mpg

    Look at the following data chart, paying attention to the ANNUAL (average) values. Seems to recover quite nicely each winter.

    http://arctic.atmos.uiuc.edu/SEAICE/timeseries.1870-2007

    So not only is the melting SEASONAL, its REGIONAL. (NH vs SH)

  6. Morgan,

    You’re right – CO2 shouldn’t affect the NH any more than the SH. That’s one of Phillips’ points. What he’s getting at with population is this…

    A Hansen co-authored paper from 2005

    http://earthobservatory.nasa.gov/Newsroom/NasaNews/2005/2005032318608.html

    And another paper in 207 here

    http://www.cbsnews.com/stories/2007/08/10/tech/main3154858.shtml

    In addition to the difference in development and industrial progression between the NH and SH, coupled with the population difference between the NH and SH that drives industry and energy use, would be expected to cause more warming and ice melt in the NH. Soot (as opposed to CO2) is not well-mixed and not global.

  7. Taking the average temperature of x locations, finding an effect and then invoking a global cause is a serious error of logic. The cause could just as well be a bunch of local effects.

    If there is a global process at work, i.e. CO2, then we should find a clear signal at pristine locations, i.e. locations remote from any human ‘local’ influence. IMO almost all the pristine locations on earth are in the SH and most are in the Southern Ocean or Antarctica. I have yet to see a pristine SH location with a 20th C warming trend.

    BTW, an interesting outcome of Anthony’s site survey would be a Pristine Index, a measure of how remote a site is from local human influences, including and especially land use changes.

  8. The main difference between the NH and SH is the land/ocean ratio.
    The amount of land surface area in the NH certainly explains the population imbalance.
    I suspect the difference in ocean volume might explain a lot of the temperature difference.

  9. stan-

    i can see how that might work if black particulates were laid on the ice. i was thinking more in terms of aerosolized particulates from fuels like coal that increase opacity in the atmosphere and block solar rays along the lines of the arguments made that pollution is masking the full extent of CO2 based AGW. would be tricky to net those out, but i now see the point you are making. thanks.

  10. Morgan,

    And now I see the point you were trying to make. The global temperature dropped precipitously following the Mt. Pinatubo erruption in 1991 because of the phenomenon you cite.

    Because they scatter and absorb incoming sunlight, aerosol particles exert a cooling effect on the Earth’s surface. The Pinatubo eruption increased aerosol optical depth in the stratosphere by a factor of 10 to 100 times normal levels measured prior to the eruption. (“Aerosol optical depth” is a measure of how much light airborne particles prevent from passing through a column of atmosphere.) Consequently, over the next 15 months, scientists measured a drop in the average global temperature of about 1 degree F (0.6 degrees C).

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  12. This report is from NASA-JPL (CalTech), not NASA-GISS. I’m starting to see a lot of differences in the work coming out of the climate research from these two institutions.

  13. The arctic responds more to ocean processes, the antarctic to a combination of land processes. Both places are a mixture of such process influeneces, but these are the dominant ones.

    From 1979 to quite recently, the Pacific spent a lot of time with higher than normal SSTs over significant areas, due to a positive PDO phase. The Atlantic was warm during the 90s and early 00s. The global system of ocean currents move heat around. It is not inconceivable that a good chunk of such heat contributed to the great melt back of this past summer in the East Siberian and Chukchi Seas. Plus, the winds, as duly noted. Now that the Pacific is drastically falling in temperature (due to La Nina and possible flip to negative PDO phase) and the Atlantic is a bit cooler as well, it will be interesting to see if there is an impact in the Arctic on some sort of delayed basis.

  14. If particulates are the problem then we are damn lucky SOBs. It’s the cheapest solution and a vast cleanup is going to happen anyway without legislation as China, India, etc., move from dirty superindustrial to clean postindustrial societies. (Besides, primitive agricultural societies are always the hardest of all on the land. Any historian knows that.)

  15. The idea that winds are causing the reduced surface area makes sense to me. I live just north of Anchorage, Alaska and have, as part of my job, dealt with maintaining ocean docks. Since sea ice can do substantial damage to docks and affects the ships calling there I have kept a fairly close watch on Cook Inlet ice for the last 12 years. Last winter’s Cook Inlet sea ice was some of the worst (i.e. thickest and most detrimental to shipping) that I have seen during this time period. Additionally Anchorage and other regions of Alaska experienced two of the coldest Novembers and Marches on record last winter. This seems terribly incongruous with sea ice extents being the least ever observed. One typical pattern of sea ice in the inlet is that winds push it to one side of the inlet or the other. Ship crews have reported that this phenomena has opened large channels for ship traffic (and likely reduced the overall area covered by ice as there are often large voids in the ice sheet).

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  17. For those who don’t know, “Tamino” [not his real name] is a troll. He posts on other sites, in the same manner, as well. Tamino’s M.O. is to throw out an allegation, then skedaddle. Whenever a neutral, moderated debate is proposed, Tamino puts his tail between his legs and runs — just like Hansen, Mann, Halpern and Gore. And that is the problem with the repeatedly falsified AGW hypothesis: those purveying anthropogenic global warming as a proven fact are not willing to defend their [falsified] hypothesis in a public forum.

    That tells you all you need to know about their confidence in AGW.

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