From the AGU Weekly Highlights, something I’ve pointed out more than a few times. See this photo of a moulin in upper Greenland, where carbon soot has collected at the bottom:
Image from National Geographic online slide show – Photo: James Balog – click for more
The authors find that BC (black carbon) emitted within the Arctic has an almost five times larger Arctic surface temperature response (per unit of emitted mass) compared to emissions at midlatitudes.
The Arctic is especially sensitive to black carbon emissions from within the region
Black carbon, also known as soot, emitted from combustion of fuels and biomass burning, absorbs solar radiation in the atmosphere and is one of the major causes of global warming, after carbon dioxide emissions. When black carbon is deposited on snow and ice, the soot-covered snow or ice absorbs more sunlight, leading to surface warming. Due to the large amount of snow and ice in the Arctic—which has warmed twice as fast as the global average over the past century—the region is likely to be especially sensitive to black carbon.
To investigate how sensitive the Arctic is to black carbon emissions from within the Arctic compared to those transported from mid-latitudes, Sand et al. conducted experiments using a climate model that includes simulation of the effects of black carbon deposited on snow.
They find that most of the Arctic warming effect from black carbon is due to black carbon deposited on snow and ice, rather than in the atmosphere. Black carbon emitted within the Arctic is more likely to stay at low altitudes and thus to be deposited on the snow and ice there, whereas black carbon transported into the Arctic from mid-latitudes is more likely to remain at higher altitudes. Because of this, the Arctic surface temperature is almost 5 times more sensitive to black carbon emitted from within the Arctic than to emissions from mid-latitudes, the authors find.
They note that although there are currently few sources of black carbon emissions within the Arctic (the most dominant ones are oil and gas fields in northwestern Russia), that is likely to change as human activity in the region increases. Therefore, the authors believe there is a need to improve technologies for controlling black carbon emissions in the Arctic.
Source:
Geophysical Research Letters, doi: 10.1002/jgrd.50613, 2013
Title:
Arctic surface temperature change to emissions of black carbon within Arctic or mid-latitudes
Abstract
[1] In this study, we address the question of how sensitive the Arctic climate is to black carbon (BC) emitted within the Arctic compared to BC emitted at midlatitudes. We consider the emission-climate response spectrum and present a set of experiments using a global climate model. A new emission data set including BC emissions from flaring and a seasonal variation in the domestic sector has been used. The climate model includes a snow model to simulate the climate effect of BC deposited on snow. We find that BC emitted within the Arctic has an almost five times larger Arctic surface temperature response (per unit of emitted mass) compared to emissions at midlatitudes. Especially during winter, BC emitted in North-Eurasia is transported into the high Arctic at low altitudes. A large fraction of the surface temperature response from BC is due to increased absorption when BC is deposited on snow and sea ice with associated feedbacks. Today there are few within-Arctic sources of BC, but the emissions are expected to grow due to increased human activity in the Arctic. There is a great need to improve cleaner technologies if further development is to take place in the Arctic, especially since the Arctic has a significantly higher sensitivity to BC emitted within the Arctic compared to BC emitted at midlatitudes.
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Russia, eh? This must be revenge for Snowden.
Even Wikipedia confirms
According to Dr. Charles Zender of the University of California, Irvine, black carbon is a significant contributor to Arctic ice-melt, and reducing such emissions may be “the most efficient way to mitigate Arctic warming that we know of”.[71] The “climate forcing due to snow/ice albedo change is of the order of 1.0 W/m2 at middle- and high-latitude land areas in the Northern Hemisphere and over the Arctic Ocean.”[72] The “soot effect on snow albedo may be responsible for a quarter of observed global warming.”[73] “Soot deposition increases surface melt on ice masses, and the meltwater spurs multiple radiative and dynamical feedback processes that accelerate ice disintegration,” according to NASA scientists Dr. James Hansen and Dr. Larissa Nazarenko.[74] As a result of this feedback process, “BC on snow warms the planet about three times more than an equal forcing of CO2.”[75] When black carbon concentrations in the Arctic increase during the winter and spring due to Arctic Haze, surface temperatures increase by 0.5 °C.[76] Black carbon emissions also significantly contribute to Arctic ice-melt, which is critical because “nothing in climate is more aptly described as a ‘tipping point’ than the 0 °C boundary that separates frozen from liquid water—the bright, reflective snow and ice from the dark, heat-absorbing ocean.”[77]
Black carbon emissions from northern Eurasia, North America, and Asia have the greatest absolute impact on Arctic warming.[78] However, black carbon emissions actually occurring within the Arctic have a disproportionately larger impact per particle on Arctic warming than emissions originating elsewhere.[79] As Arctic ice melts and shipping activity increases, emissions originating within the Arctic are expected to rise.[80]
http://en.wikipedia.org/wiki/Black_carbon
We I was young and the ice age was pending it was proposed we could stave off the glaciation by spraying black carbon on the advancing ice. I recall that people did experiments using this technology to see if they could calve icebergs, to be towed to fresh water poor regions.
Then it was all SOx driven aid rain destroying European forests so everyone began building taller chimneys.
Back in the late 1970’s, when the concern was Global Cooling and a second “Little Ice Age,” one plan that was proposed was to dust the entire arctic with black soot. Looks like we have done it, though not on purpose.
‘
And guess what? It isn’t working. Temperatures at the North Pole Camera have been below the freezing point of salt water for over a day now. http://psc.apl.washington.edu/northpole/PAWS819920_atmos_recent.html
Once Alarmism goes out of style, I hope the Big Chill looming in our future melts away. An arctic without ice in the summer would be a very nice thing.
May I suggest “soot” for “black soot”?
Does not the carbon black on the ice surface get covered by subsequent snow fall?
How long does the soot stay on the ice surface before it gets buried by more snowfall?
Doesn’t the duration of the soot on the surface determine to a large degree how much surface melting occurs?
If there is surface melting, doesn’t the melt water wash the soot into localized areas of lower elevation, which, presumably causes localized melting as opposed to large scale melting?
How do models consider any of these factors?
Or do the models just assume that the soot just sits in one spot all year long?
One must assume that in prior geologic eras, massive volcanic eruptions deposited massive amounts of soot, basically all at once, on the surface of the arctic ice. Did this cause the ice sheets to disappear? If not, why not?
I don’t see why they didn’t expect to see this. Ice has an almost perfect reflection surface, put something that is almost a perfect black body on top of it and absorbed energy changes as far as is possible. I would have to run a series of experiments to put actual numbers on it, but the common sense factor of this seems evident. Occasionally the universe throws a curve ball at ya, but usually only on really large or really small scales.
The problem here though is they do all their “experiments” in a computer rather than in the universe. Would have to see the methodology to see if they used any actual observations such as solar intensity, shine angle, carbon absorption rate/conversion of effective solar to temperature and length of day. Such a simple model could tell you alot about what effect black carbon “might” have, but until you instrument the heck out of a patch with alot of black carbon and a control patch with little to no black carbon and measure the actual on the ground effect you have not done a real experiment.
They note that although there are currently few sources of black carbon emissions within the Arctic (the most dominant ones are oil and gas fields in northwestern Russia), that is likely to change as human activity in the region increases.
However, prior to 2000 there were large BC emissions from Soviet era industries located in northern Russia. Almost all of which got shut down in the aftermath of the 1998 Russian Financial Crisis.
Large amounts of the BC was embedded in multi-year sea ice. When the BC emissions went, so did aerosols from the same sources. Less aerosols = less aerosol seeded clouds = more solar insolation which increased sea ice melt and the embedded BC accumulated on the sea ice surface. And surprise, surprise, we got accelerating Arctic sea ice melt after 2000. By this year, almost all the sea ice with high levels of BC has melted out. And again, surprise, surprise we see Arctic sea ice start to increase again.
“Black carbon ….. is one of the major causes of global warming, after carbon dioxide emissions.”
Is it clear that soot comes after CO2 or is this another “repeat after me” assumption?
CO2 doesn’t seem to be working all that well as the cause, so we need to switch to carbon, I suppose. So, is the soot deposition increasing from the growth of India and China, or decreasing because the polluting west pollutes less?
JA says: ” One must assume that in prior geologic eras, massive volcanic eruptions deposited massive amounts of soot, basically all at once, on the surface of the arctic ice. Did this cause the ice sheets to disappear? If not, why not?”
The really explosive eruptions deposit rhyolitic or andesitic ash, which is light coloured (think pumice). So not such a big effect as soot.
OK, do the satellites support that “arctic warming twice as fast” statement? or is it all based on the surface stations which do not for the most part exist there?
I don’t know why this article bugs me so much. I read them all, but only comment occasionally when something either grabs my funny bone or sticks in the craw.
Did anyone know they apply BC to golf coarse greens to heat thing up some for earlier growing season in colder climates. I even apply Ground up Charcoal or biochar it to my garden in the late winter over the snow to get things going faster.
I have been in the snow plowing business for many years and if you can scrape the snow and ice so the pavement shows a little bit the snow and ice melts much faster when the sun is up.
Any bit of black or even something that has a color other then white will absorbs the suns rays and heats up. Ever see tree bases in late winter, they absorb the sun’s rays and the snow melts around their base.
BC is easy to capture.
I do feel the Southern Hemisphere Sea Ice is at record highshttp://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html and has been increasing while the sun has ben decreasing in energy output because BC is a lot less there.. There is only a little bit of BC that falls from the sky in the S hem not like the N hem.
Remember, BC is only an issue when the sun is shining during the spring, summer and early fall months. Not an issue at all during the winter months.
Oops S hem sea ice link..
http://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html
“Black carbon ….. is one of the major causes of global warming, after carbon dioxide emissions.”
When I read that, I quit reading. The author(s) lost all credibility in my eyes.
On a (far) side note there is negligible black soot in the Antarctic and no reduction in ice extent.
I’ve seen ducks kick dirt onto the ice to give them some drinking water, and eventually open up some swim space. Same deal — black earth absorbs heat, melting ice. ERGO…. ducks cause global warming (or something)?
It’s all that soot that Santa disturbs going up and down chimneys.
So, geek49203, are those ducks heavier or lighter than a witch?
We ‘Flat Earthers’ have been pointing out that carbon black was likely to be a huge factor for years. The sad reality is that for a fraction of the money squandered on AGW hype over CO2, a real treaty and shared technology for reduction of carbon black could have been achieved and implemented.
“Especially during winter… response from BC is due to increased absorption when BC is deposited on snow and sea ice…”
During winter there is no sunlight to be absorbed, the BC can only aid the radiation of heat to space.
“””””…….Owen in GA says:
August 13, 2013 at 6:21 pm
I don’t see why they didn’t expect to see this. Ice has an almost perfect reflection surface, put something that is almost a perfect black body on top of it and absorbed energy changes as far as is possible. I would have to run a series of experiments to put actual numbers on it, but the common sense factor of this seems evident. Occasionally the universe throws a curve ball at ya, but usually only on really large or really small scales……..”””””””
Well melt ice has an almost perfect reflectance of 2-3% of the incident solar radiation; whatever almost perfect is. Typical photographs of glaciers, show significant surface deposits of black materials, and if those deposits were almost perfect blackbodies, they would continue to melt their way down. As particles get smaller the surface area to mass ratio gets larger, so that presumably means the equilibrium Temperature goes up; but if the insolation is low enough they might still not reach water melting Temperature.
But ice is not the great reflector its cracked up to be; it’s like glass.
But…..but……but……..today we also had this on E&E’s Climatewire:
Climate benefit of cutting soot and methane may be lower than initially thought — study
Stephanie Paige Ogburn, E&E reporter
Published: Tuesday, August 13, 2013
Correction appended.
In recent years, scientists and policymakers have focused on controlling climate pollutants other than carbon dioxide as a potential way to curb global warming in the short term. Curbing emissions of methane and soot, also called black carbon, could limit short-term global warming, the idea goes, because these substances have a strong effect on global temperatures in the short term.
Plus, at least politically, such short-lived climate pollutants are often seen as easier to control than carbon dioxide. Last year, a coalition of countries including the United States formed the Climate and Clean Air Coalition, dedicated to reducing these types of emissions (ClimateWire Feb. 16, 2012).
A study published online yesterday in the Proceedings of the National Academy of Sciences, though, says the climate benefit of curbing methane and black carbon may not be quite as large as some previous studies have estimated.
The authors of the new paper, Steven Smith and Andrew Mizrahi, say that even if the maximum reductions on these two pollutants were put into place, there would be only a “modest” reduction in average global warming of 0.16 degree Celsius (0.28 degree Fahrenheit) by 2050.
Previous estimates have put the reduction closer to 0.5 C, or 0.9 F.
Reducing methane and black carbon emissions “is likely to have a climate benefit. It’s just that this climate benefit is smaller than we previously thought,” said Smith, a senior scientist at the Joint Global Change Research Institute, a joint venture of the University of Maryland and the Pacific Northwest National Laboratory.
Questioning assumptions of models
As a result, the paper authors write, a comprehensive strategy that includes reducing emissions from carbon dioxide and other long-lived greenhouse gases as well as short-lived pollutants should be the main focus of policy efforts to stabilize the climate.
“We hope that this scientific information will help inform the discussion,” Smith said.
The researcher pointed out that there are still strong reasons to reduce emissions of such short-lived pollutants, because they can have serious negative health consequences.
“We are talking about people that are dying prematurely and having less quality of life because of air pollution worldwide from particulates and also ground-level ozone,” Smith said.
There are a few reasons Smith’s calculation of the benefits of curbing such pollutants differs from some earlier ones.
The researchers used a model that assumed existing trends in pollution control would happen regardless of any additional policies. So as incomes rise and cookstoves get cleaner and put out less black carbon, for example, the base-line model assumed this trend would continue until the end of the century.
They also took into account the fact that generally, as incomes go up, air pollution decreases. This has happened in the United States and Europe, and their model assumed it will happen elsewhere as well.
The model also assumed that methane emissions will be reduced in the future, because capturing leaking methane, which can be used as a fuel, is an economically sensible thing to do.
“You have this declining base line, so we did everything relative to that,” Smith said.
Behavior may not follow economics
That approach makes sense in some ways, said Drew Shindell, a climate scientist at NASA’s Goddard Institute for Space Studies, but the assumptions that underlie it may not play out that way in the future.
Shindell was the lead author of a 2012 paper in Science that estimated around a 0.5 C reduction by 2050 if short-lived climate pollutants were curbed. Shindell’s paper had a different outcome because his model did not automatically assume that future emissions will continue to go down, he said. So in a way, the two studies ask different questions.
“Their question is really, assuming a world where everything economically attractive has already happened, then what extra benefit can you get by targeting these [short-lived] pollutants?” Shindell said. “That’s a really important difference.”
To Shindell, it is important that policymakers understand that policies need to be put into place to see such emissions reductions — that they are not automatically going to happen.
Another difference between the model used in Smith’s study and the ones Shindell has used is that it doesn’t include the additional warming effects of black carbon based on where it falls.
“If soot gets carried over the Himalayas, it has a much bigger physical impact,” Shindell said.
Smith said he hopes to look at the regional impacts of black carbon in the future.
“We know that black carbon has a disproportionate effect in the Arctic in part because if you deposit black soot on snow or ice, that’s extra warming that doesn’t occur here,” he said.
Correction: An earlier version of the story incorrectly described the researchers’ base-line model regarding cookstoves.
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Corrigendum: Models, what can you do?