A new modeling study from NASA confirms that when tiny air pollution particles we commonly call soot – also known as black carbon – travel along wind currents from densely populated south Asian cities and accumulate over a climate hotspot called the Tibetan Plateau, the result may be anything but inconsequential.
In fact, the new research, by NASA’s William Lau and collaborators, reinforces with detailed numerical analysis what earlier studies suggest: that soot and dust contribute as much (or more) to atmospheric warming in the Himalayas as greenhouse gases. This warming fuels the melting of glaciers and could threaten fresh water resources in a region that is home to more than a billion people.
Lau explored the causes of rapid melting, which occurs primarily in the western Tibetan Plateau, beginning each year in April and extending through early fall. The brisk melting coincides with the time when concentrations of aerosols like soot and dust transported from places like India and Nepal are most dense in the atmosphere.
“Over areas of the Himalayas, the rate of warming is more than five times faster than warming globally,” said William Lau, head of atmospheric sciences at NASA’s Goddard Space Flight Center in Greenbelt, Md. “Based on the differences it’s not difficult to conclude that greenhouse gases are not the sole agents of change in this region. There’s a localized phenomenon at play.”
He has produced new evidence suggesting that an “elevated heat pump” process is fueling the loss of ice, driven by airborne dust and soot particles absorbing the sun’s heat and warming the local atmosphere and land surface. A related modeling study by Lau and colleagues has been submitted to Environmental Research Letters for publication.
A unique landscape plays supporting actor in the melting drama. The Himalayas, which dominate the plateau region, are the source of meltwater for many of Asia’s most important rivers—the Ganges and Indus in India, the Brahmaputra in Bangladesh, the Salween through China, Thailand and Burma, the Mekong across Laos, Cambodia and Vietnam, and the Yellow and Yangtze rivers in China. When fossil fuels are burned without enough oxygen to complete combustion, one of the byproducts is black carbon, an aerosol that absorbs solar radiation (Most classes of aerosols typically reflect incoming sunlight, causing a cooling effect). Rising populations in Asia, industrial and agricultural burning, and vehicle exhaust have thickened concentrations of black carbon in the air.
Sooty black carbon travels east along wind currents latched to dust – its agent of transport – and become trapped in the air against Himalayan foothills. The particles’ dark color absorbs solar radiation, creating a layer of warm air from the surface that rises to higher altitudes above the mountain ranges to become a major catalyst of glacier and snow melt.
- CLICK TO VIEW ANIMATION – Tiny, dark-colored aerosols — specifically black carbon — travel along wind currents from Asian cities and accumulate over the Tibetan Plateau and Himalayan foothills. Seen here as a light brown mass, these brown clouds of soot absorb sunlight, creating a layer of warm air (seen in orange) that rises to higher altitudes, amplifying the melting of glaciers and snow. Credit: NASA/Sally Bensusen Nicknamed the “Third Pole”, the region in fact holds the third largest amount of stored water on the planet beyond the North and South Poles. But since the early 1960s, the acreage covered by Himalayan glaciers has declined by over 20 percent. Some Himalayan glaciers are melting so rapidly, some scientists postulate, that they may vanish by mid-century if trends persist. Climatologists have generally blamed the build-up of greenhouse gases for the retreat, but Lau’s work suggests that may not be the complete story.
Building on work by Veerabhardran Ramanathan of the Scripps Institution of Oceanography, San Diego, Calif., Lau and colleagues conducted modeling experiments that simulated the movement of air masses in the region from 2000 to 2007. They also made detailed numerical analyses of how soot particles and other aerosols absorb heat from the sun.
“Field campaigns with ground observations are already underway with more planned to test Lau’s modeling results,” said Hal Maring who manages the Radiation Sciences program at NASA Headquarters in Washington. “But even at this stage we should be compelled to take notice.”
“Airborne particles have a much shorter atmospheric lifespan than greenhouse gases,” continued Maring. “So reducing particle emissions can have much more rapid impact on warming.”
“The science suggests that we’ve got to better monitor the flue on our ‘rooftop to the world,” said Lau. “We need to add another topic to the climate dialogue.”
h/t to Dr. Roger Pielke Sr.
Related Links:
> The Dark Side of Carbon: Will Black Carbon Siphon Asia’s Drinking Water Away?
> Soot is Key Player in Himalayan Warming, Looming Water Woes in Asia
> Asian Summer Monsoon Stirred by Dust in the Wind
> A Unique Geography — and Soot and Dust — Conspire Against Himalayan Glaciers
Gretchen Cook-Anderson
NASA Earth Science News Team
Shouldn’t the H-word in the headline be “Hima-LAY-an?” As it is now, it appears to rhyme with “Somalian.”
AdderW (16:17:14) : “Since english isn’t my first language I should have double checked. How many languages do you speak? I speak 4, but I obviously do not master english yet :)”
I speak every language except Greek. Go ahead, try me! 🙂
As climates change, so do fashions. According to my sources, dark colors will once again be all the rage among peppered moths in the coming years.
@Gary Young Hladik
Fira lira lattra, tvo sworte tattra, en bröhönting o en swort 🙂
Soot article word art
AdderW (16:40:43) : “@Gary Young Hladik Fira lira lattra, tvo sworte tattra, en bröhönting o en swort :)”
Sorry, that’s Greek to me! 🙂
(A joke that goes back to William Shakespeare, or even earlier. See
http://en.wikipedia.org/wiki/Greek_to_me
Thanks for being a good sport.)
AdderW (16:40:43), and of course I forgot to ask what your joke was.
As I understand it, these “brown clouds” can be quite large – several miles across, and hundreds of meters high, and last anywhere from a few days to a week before they dissipate. They’ve been known to suffocate livestock, and are of course dangerous to humans with health issues such as asthma. It seems logical that they would absorb energy from sunlight and gain in temperature more than the surrounding air, and that if they came into contact with glaciers could cause higher melt rates. As to just how much melting they could cause, it doesn’t seem to me it could be a considerable amount, since they don’t last that long.
Soot, though, is considered to be an aeorosol, which are supposed to have an overall cooling effect. Expounding a bit on what George E. Smith (15:16:26) said above, perhaps it is the size of the sooticle which determines its overall climatic effect, with smaller particles rising higher along with other aerosols, blocking sunlight, and causing cooling, and larger, heavier ones traveling in lower flying brown clouds, adding some of their accumulated warmth to glaciers as well as depositing directly onto the ice and adding insult to injury by boring holes into it.
The bottom line is of course that it is real pollution that should be dealt with, not C02, which is harmless.
What would be interesting is to see if the hypothesis here is borne out in actual temperature change in the L.A. Basin. The 60s, 70s and 80s had high particulate counts that have been greatly reduced over the bast 20+ years. Has L.A. cooled with its reduction in particulates (i.e. soot)?
Doug
@LPM
‘First let me say that I know next to nothing about climate science,’
Apparently not even the (in)famous climate scientists do, even though they, as dare I say everyone, goes through the seasons every year.
Personally I think most of every day rational people know more about actual climate science ’cause of a neutral and objective stance to pretty much everything that has to do about the weather, i.e. there’s no readily inference of every negative bit into belief and faith about doom and gloom to come.
The MannStickBear parade and Al Gore can trumpet their horns all they want but it still won’t change the fact that not even they would want to go back to the median temperatures that is the schtick.
Are they pretty sure that soot is also called black carbon? Because that’s the first time I’ve ever heard of that. I’ve heard of carbon black, but it’s not soot.
This makes me wonder how many other things we could be researching to help countries get rid of real pollution, such as soot, untreated waste water, ocean dumping of waste, landfills, contaminated water run-off from coastal cities into the ocean, etc. if all the research money wasn’t going to the global warming scam.
The Greens are going to turn the Earth brown if they keep diverting resources to a non-problem.
who remembers when soot was a prize … in the 1970s the very same liberals wanted to coat the poles with carbon black to stop the for sure coming ice gae.
GISS Model E has a +0.1C impact built-in for Black Carbon on Snow (and Ice).
http://img509.imageshack.us/img509/8388/modeletempimpactst.png
I’m not sure I really buy this explanation. We all know black surfaces on snow can warm up and melt through the snow or the ice.
But the last snow and ice to melt in the spring is the snow/ice covered by soot. The soot accumulates on top (eventually) and starts to act as an insulating layer and keeps the cold in and the warmth out. Many glacial melting fronts actually look black rather than white because this soot and material tends to (eventually) accumulate on top forming an insulating layer and pushes the glacial front out farther than it would have been without being covered in soot and dust.
In any event, the negative Aerosols impact on temperature does not seem to actually occur. The Black Carbon/Soot that goes with it seems to have a greater warming influence than the sulfate Aerosols negative impact.
There is a reason why the northern hemisphere has warmed faster than the southern hemisphere and why Asia seems to be warming faster than other places on the globe right now. And it is not because the negative impact of Aerosols which should have affected the northern hemisphere more than the southern and Asia now.
In the chart above, you might have noticed the -0.6C impact of Aerosols which allows the climate models to come close in hindcasts to the actual (artificially adjusted upward) temperature trend.
It doesn’t hold together. Black Carbon – Aerosols – Artificial Temperature Adjustments – Normally called Fudge Factors.
“”” AdderW (16:17:14) :
George E. Smith (15:50:11) :
“”” AdderW (13:11:06) :
“The science suggests that we’ve got to better monitor the flue on our ‘rooftop to the world,” said Lau. “We need to add another topic to the climate dialogue.”
Is this another weird scientific term? flue??!!
soot is soot, don’t make it into a disease “””
Well influenza is “flu” and not “flue” which is another name for part of a chimney.
So the speaker Lau was speaking quite correctly.
Anybody who didn’t get their education from a California Public School would know that one.
Yes my bad, I should have looked it up. Since english isn’t my first language I should have double checked. How many languages do you speak? I speak 4, but I obviously do not master english yet 🙂 “””
Well if you speak four languages; then you very likely didn’t get your education from a California Public School; so we’ll give you a pass on the English; which I often say is the only foreign language I ever studied.
In fairness to you I should say that flue is somewhat archaic; and in particular it is not so common in America, as it likely is in other English speaking countries; but if you think “chimney” you’ll roughly have the gist of it.
Come to think of it; we used to have a very nice African chap working in our company cafeteria; washing the dishes specifically; in an otherwise all Mexican restaurant crew; who of course conversed among themselves in Spanish leaving our African friend in the dark (he was from Ghana), so he just washed the dishes, in his business suit, plus apron, and he always wore a nice bow tie. I asked him why he didn’t get out of the sink and get himself a much better job, with workmates who would converse with him.
Turns out he was fluent in English, French, Spanish plus three African Languages of the Bantu family, and he wasn’t at all interested in his crew mates knowing that he understood every single word they said about him; and he really didn’t have to think much while washing the dishes quite happily.
BIll Illis,
You seem to forget that the soot that you see is not so much soot as it is other particulate. It’s not because of soot that trees grow on a glacier, it’s because of the accumulated soil, but that pretty much only adheres to some glaciers, if not most, due to the fact that every time it snows a lot of white is added that offset the soot capability to warm, and that’s not even taking into consideration the offset that hundred of feet of ice tends to have on anything that want to get warm on the surface.
And never to forget that a retracting glacier leaves mountain sides bare and those mountain sides are no small variable to consider as a heat sink working from below. Now couple that with weight pressure and friction…. or have you never wondered why there is running water high up in the mountains from glaciers when the temperature reads even as high as minus 20?
I don’t trust these studies about soot any more than I trust studies of CO2. These scientists work in the same departments and on occasion write papers about CO2 based warming – thus they’re unreliable.
I think our cause is damaged when we readily accept science that agrees with our beliefs, while always rejecting science that doesn’t. We’re not on message. We need to be skeptical about this, too, otherwise we risk losing integrity by seeming to blindly embrace ANYTHING that contradicts AGW.
1DandyTroll (18:26:06) : (nice nic by the way).
GISS Model E builds in almost the same impact for Black Carbon on Snow as the Solar Irradiance increase through the past century.
Does that seem reasonable to you.
http://data.giss.nasa.gov/modelforce/RadF.gif
During parts of the ice ages, huge dust levels are recorded in the ice layers for thousands of years and this didn’t seem to reverse the ice ages. It wasn’t until solar irradiance picked up that the ice finally melted back.
http://img205.imageshack.us/img205/3616/dustandiceages.png
A man from Orissa in India told me that in some areas laundry on a washing line gets black in one day. There are plenty of big coal and steel plants in East-central India, and environment rules are not seriously enforced on big companies. Also, millions of people cook on wood fires, plus hundreds of thousands of old diesel trucks ply the sub-continent.
China is another story.
JerryM (13:34:02) :
Thanks, I remember it now. After some quick googling, I found this document at Dr. Ramanathan’s website:
I think that the following excerpt is important, so did he:
“It is important to note that our simulations do not contradict the surface
cooling effect of ABCs [Atmospheric Brown Clouds]. In fact, in our simulations, ABCs cooled the surface over most of the plains in Asia, while warming the overlying free atmosphere. The surface cooling and the atmospheric warming are two sides of the same energy-balance coin: absorption by ABCs causes solar radiation that otherwise would have warmed the surface to instead warm the free atmosphere from1 to 5 km above the surface. In addition, the ABC induced warming was due to air pollution originating from all of Asia and not just S Asia, as can be seen most every day from satellite particle sensors. The latter two points were missed by the media covering the finding.”
The question that came to mind when I was reading this and some of the other documents he listed in his bibliography was, What happens to the heat in the atmospheric black carbon and dust blanket (or parasol) when the sun goes down? Perhaps I just missed it, or he addresses it in one of his other papers? I will take a closer look — sometime.
acementhead;
I apologise on the”carbon monoxide ” inclusion as a forcer. It’s just that finding 35-40 other environmental forcing mechanisms for global warming is quite a treat! I got overenthusiastic.
What slice of the globlawarming increase pie can be claimed by each forcing and at any one time and for what duration? And will it change seasonally? That’s gonna be tough.
The science isn’t settled.
Troels Halken (11:32:17) :
http://pielkeclimatesci.wordpress.com/2009/12/10/news-bbc-article-himalayan-glaciers-melting-deadline-a-mistake/
So there is a warming but the glaciers does not melt?
Hmm…
Proofreading FAIL !
see more Epic Fails
This sounds way more plausible than CO2 to me, but its unlikely to be a “cause” of global climate change on its own. I suspect any human contribution to climate (+ and -) will be though the combination of lots of little effects like more GHG’s, increased soot and particulates in the air, urban heat islands, land use changes, deforestation, changes in water courses etc.
Shouldn’t more soot promote cooling though? I thought thats what volcanic eruptions did with all the ash in the air – perhaps soot concentrations in the high atmosphere don’t have the same effect or concentraiton? Maybe we need to start poking Mt Pinatubo, El Chichon and Mt St Helens with a big stick or take more long haul flights.. 😉
As a AGW skeptic now quickly becoming a denier hahaha from the emails etc. I would say that this is one point the warmistas and coldistas could agree on, and say that humans could influence to some extent locally… ice on mountains and maybe NH and SH poles. But for Gods sake forget C02 etc…! But then what would eruption of as volcano such as Mt Helen have had on surrounding ice?
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