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
Soot, eh?
I have forgotten – how many million tons of space dust hits the atmosphere each year though meteors, etc?
Just wondering…
so it would seem the solution to Himalayan melting is…
wait for it…
MORE economic development in the area. Which requires the availability of abundant, cheap energy supplies, which currently are only mass produced through the combustion of fossil fuels.
AHHHHHHHHHHH, but the soot wouldn’t be as damaging IF C02 levels were brought down.
(the easy answer by the AGW supporters)
This is an example of man-made climate change I can believe in! Fortunately it’s relatively cheap and easy to reverse. Too bad there isn’t more focus on fixing these types of problems instead of almost solely focusing on CO2 emissions.
A few years ago a UCI report said that up to 40% of the warming in the Arctic is due to black carbon, apparently most of it from China. If we can convince China to control pollution from diesel trucks we can greatly reduce the black carbon darkening the ice in the Arctic at a cost of about $250 per truck.
Is this like the same kind of soot that from 1940 to 1975 caused a net cooling?
Just askin’.
I question this conclusion. Dust is a FAR greater particulate in the atmosphere than carbon soot is. The depiction of purple and white clouds gives a very wrong impression and leads the reader to think the colorful but menacing looking clouds are made up of just soot. Nothing could be further from the truth. This could be another way to bring about the green political change NOAA seems to be a party to but will be plagued with the same questionable scientific underpinnings.
I’m glad you are highlighting this.
I think most on this blog are quite sceptical about AGW claims, but if one accepts that some warming due to CO2 is quite plausible, the sensible policy action is to tackle pollution first.
In my view AR4 underestimates the forcing from soot, and it is much cheaper and more practical to tackle this than CO2 emissions.
Various policies appear plausible : one is to furnish families in developing countries with better cooking appliances. Another is strengthening controls on diesel emissions, and a third would be to reduce wild fires by better management of the countryside.
Apparently coal fired power stations are not a problem.
Put the smoke through a water bath trap. How hard it that?
Deutz does it on their permissible diesel engines, last I looked.
Sounds a lot more scientific than the guff we get from alarmists. Satellite photos from NASA regularly show these clouds of muck parked up along the mountains and in parts of Northern India you can chew the smog
I’ve just emailed following message to Mr. Piers Corbyn
“Mr. Corbyn
There is a snow storm in Copenhagen tonight. Congratulations. I personally and some of the people I correspond with, consider you a weather forecaster of our age.
All the best.
Regards M. Vukcevic”
WA News No 91 – 30th Nov 2009
WeatherAction releases free long range forecast for Copenhagen
Climate summit to be hit by blustery deluges, probably turning to snow or blizzards and icy blasts in the region at times – especially heavy when President Obama visits
Honest Greens called on to “Jump from the Titanic before you and what you stand for gets dragged down with it”….
http://www.weatheraction.com/displayarticle.asp?a=114&c=1
Click here to view this news item
http://www.weatheraction.com/docs/WANews09No91.pdf
I know they’ve been quiet lately, but anyone want to place bets on how long it will take RC to “debunk” this research? Or had they done this already 😉
“Progress will come by more systematic comparisons among studies to identify key uncertainties. The unambiguous distinction between individual aerosol species within models will eventually become possible by direct observation as a result of more discerning instruments. Nonetheless, models will remain valuable for their ability to distinguish natural and anthropogenic sources of the same aerosol species. While Bellouin et al. assume that all soot particles over the ocean are anthropogenic, naturally occurring forest fires contribute as well. As consensus emerges regarding the global aerosol forcing, attention will turn to regional values that cause local changes to climate and heat redistribution by the atmosphere. Because of the added complexity of cloud physics, the aerosol indirect effect may be even more resistant to consensus. Aerosol forcing remains a crucial problem because its offset of greenhouse warming is expected to decrease with time as governments address the health problems associated with aerosols. Because of their comparatively short lifetimes, the concentration of aerosols decreases much faster than that of CO2 given a reduction in fossil fuel use. [B]Regardless of the absolute amount of the forcing, future reductions in aerosol emissions will be a positive forcing, amplyfying the warming effects of increasing greenhouse gases[/B].”
http://www.realclimate.org/index.php/archives/2006/02/an-aerosol-tour-de-forcing/ – attempt at emphasis mine
I think he’s saying it won’t be a consensus issue any time soon (i.e. it’s debatable) but at the same time the net effect of removal of aerosols (which I believe includes soot right?) will be a positive forcing… “regardless”.
Please correct me if that summarization of his summarization is off, but my reading does seem to conflict with the article for the Himalayas.
We should not read into this more than what it is, a regional study – whereas the RC analysis is intended to be global… but if the heat gain from soot > heat loss from other aerosol shading in this instance, this could challenge the assertion that the net global effect of aerosols is the reverse.
…or I might not know what the heck I’m looking at
We need more CO2. Burn up that soot in more efficient stoves.
Combine the soot effect with glaciohydraulic supercooling and you are going to have a lot of ice melt.
I can see where soot causes more melt, which causes more seepage to the bottom of the glacier, which causes glaciohydraulic supercooling, which spits more dirt material to the surface.
“We need to add another topic to the climate dialogue.”
might want to double check your ‘5 times the rate’ thermometers before you head down that road, Mr. Lau. I’m just sayin…
In China, the “pollution” is more dust than soot. Yes, that dust is born of farming and irrigation practices. But nonetheless, most people are mistaken about the amount of soot in China’s atmosphere compared to the amount of soft yellow silt dust.
OT: can anyone tell me how the erruption of the Mayon volcano may impact on cooling? Is this a possible climate altering event or small fry?? Please excuse my mistake if this is the wrong area to post a question not quite in line with the thread under discussion.
Kind regards
My question is this, if the glaciers lose more ice in summer months due to extra warmth, will this stop all those people downstream from having water? The way they talk about it they make it sound like a disaster, but it will still rain / snow there regardless of temp, and the rivers will still flow! They may get more variation in flow, but they will still have water – whats the issue?
No one complained when the glaciers used to shrink in the past?
“travel along wind currents from densely populated south Asian cities and accumulate over a climate hotspot called the Tibetan Plateau”
Sounds like another reason to bring manufacturing back to the United States. Pollution control is stricter here = less soot. Quit outsourcing everything to China and India. Build closer to market = less fuel used = less soot. But all we hear is that the developed countries are supposed to cut back which would result in even more soot.
An additional thought… the models assume future aerosol reductions as a net positive. If it was, in fact, a net negative or neutral it means their emissions targets and other future projections are completely off… which means the targets they’re talking in Copenhagen are overstated
Hehe, and that’s assuming the rest of the models and projections are accurate. Which is not a given 😉
By “black carbon” I assume they really mean “carbon black” correct?
I don’t know why things are so dumbed-down these days.
Here is one of the better articles on China’s suspended particulate matter.
http://docs.google.com/viewer?a=v&q=cache:oY78Kz1LE7wJ:scialert.net/pdfs/tasr/2006/91-96.pdf+total+supended+particulates+in+China%27s+atmosphere&hl=en&gl=us&pid=bl&srcid=ADGEEShzryBVWiXBL4kaS6QwiB3Rmmn4fI1yW50ed9Jlw2fG-_9lxppclM_xVa27mjoGpIKrRmuQ5WJHeU4lR0qmuwa4efuF7M2wzsiJnmfKLBdyt7KDosVpUv5SK8hvteeXxwl8rfqz&sig=AHIEtbRcxrtdFoGwXJRWjcUjRoCPydqCPA
Yeah, I’m with Pamela. I’m not sure that these particles are just doing warming.
Carbon particulates, when they fall out of the atmosphere, can depress the freezing points of the glaciers, increasing the range at which the surface of the glacier can melt.
It’d be nice to get some surface scrapings of the glaciers from the area and check them for particulate matter concentrations over the span of a year. In fact, I call dibs on this! NSF money here I come!
Looky, ANOTHER computer model that confirms the researcher’s theory. XBox climate science at its best. These guys can prove ANTHING with their models! On the bright side, the People are Evil Freaks are not blaming the West this time. Welcome to the club guys.
OR
Perhaps this study is not junk science with the model, data, and methods, programmed, adjusted, and contrived to give the desired result.
How can you tell?
oops, Nigeria, not China
The problem here being that China releases immense amounts of soot from uncontrolled coal mine fires. I wonder if anyone has discussed putting those out?