The Effect Of Soot On Arctic Summer Ice Extent

Scientists tell us that Arctic summer ice loss is primarily due to soot – not CO2.

http://www.scientificamerican.com/article.cfm?id=impure-as-the-driven-snow

Zender, physicist Mark Flanner and other colleagues built a model to examine how soot impacts temperature in the Arctic and Antarctic regions. Temperatures in the northern polar region have already risen by 1.6 degrees Celsius (2.88 degrees Fahrenheit) since the dawn of the Industrial Revolution. The researchers incorporated information on soot produced by burning fossil fuels, wood and other biofuels, along with that naturally produced by forest fires and then checked their model predictions against global measurements of soot levels in polar snow from Sweden to Alaska to Russia and in Antarctica as well as in nonpolar areas such as the Tibetan Plateau.

Unfortunately, the soot problem extends beyond snow, he says, noting that similar studies are needed to assess how the smut affects the melting of sea ice. That meltdown may be the impetus for an accelerating doom as it opens up shipping lanes previously blocked by ice in the Arctic Sea. “Those ships are great emitters of soot,” Zender points out, adding that, “putting a locally heavy source in the Arctic in the early spring,” is virtually guaranteed “to polish off the summer sea ice.”

Dr. Hansen confirmed this in 2003 :

Plausible estimates for the effect of soot on snow and ice albedos
(1.5% in the Arctic and 3% in Northern Hemisphere land areas)
yield a climate forcing of 0.3 Wm2 in the Northern Hemisphere.
The ‘‘efficacy’’ of this forcing is2, i.e., for a given forcing it is twice
as effective as CO2 in altering global surface air temperature. This
indirect soot forcing may have contributed to global warming of
the past century, including the trend toward early springs in the
Northern Hemisphere, thinning Arctic sea ice, and melting land ice
and permafrost.

The soot effect on snow albedo may be responsible for
a quarter of observed global warming.

The chart below shows Hansen’s calculations of the temperature effect of soot by season and latitude. He shows 1-2C warming across the Arctic due to soot.

In other words, reducing CO2 emissions (if it were possible) would have very little   effect on Arctic ice, because they aren’t the primary cause of the problem.



About stevengoddard

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5 Responses to The Effect Of Soot On Arctic Summer Ice Extent

  1. Scott says:

    Something I’ve wondered about is how the Icelandic volcano eruption earlier this year effected the Arctic melt season. It might provide an alternate explanation for why parts of the ice melted all the way to the pole this year.

    -Scott

  2. Scott :

    The extensive tundra fires seen over Russia this summer may well have played a part too.

  3. R. de Haan says:

    “Temperatures in the northern polar region have already risen by 1.6 degrees Celsius (2.88 degrees Fahrenheit) since the dawn of the Industrial Revolution”.

    Show me the data set!

    They can’t because they haven’t got any reliable temperature data from the Arctic for that period of time.

    Besides that, there always has been soot and dust in the atmosphere.
    Think dust storms, forrest fires, natural coal fires and volcano’s.

    Especially volcanic activity was much higher during the Little Ice Age period.

    Read the message between lines: It’s about us burning coal, it’s about us burning fossil fuels, it’s about us having a civilization.

    They can stick their report where the sun don’t shines.

  4. Dave says:

    Wrong. As pointed out in the comment sections of the sci-am article:

    “may be responsible for as much as 94 percent of Arctic warming” is likely a misleading or incorrect reporting of the results of the Flanner et al. JGR paper. As I read the paper, they performed two simulations: one for a strong boreal forest fire year and one for a weak one. In the strong year, BC did indeed lead to 1.6 degrees of warming in the calculation. However, in the weak year, there was only 0.5 degrees of warming. Since the Arctic has, on average, warming of about 1.6 degrees, BC “only” contributes 65% of Arctic warming on _average_ in the Flanner study.

    Moreover, even “65%” is misleading, because warming agents can add up to more than 100%, if there are also cooling agents. Certainly Flanner himself contributed to a study for AMAP (Quinn et al. 2008) which suggests that BC, at about 0.7 degrees of warming, contributes only about half as much warming as CO2 (and CH4, O3, and presumably the other GHGs also have their own contributions).

    Given that this article has been cited in Congressional Testimony by Pielke Sr., it is unfortunate that it was written in a way that could be easily misinterpreted to magnify BC’s importance and therefore decrease CO2s apparent importance.

  5. Amino says:

    alrmism in the 70’s, alarmism now, same thing, no difference, just switch cooling for warming

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