These two satellite images show how aerosols can obscure the land and sea beneath, blocking incoming sunlight. On the top, aerosols over northeastern India and Bangladesh partially obscure the Ganges River and then are swept out over the Bay of Bengal. Notice how the high-altitude air over the Himalayas, near the top of the image, is clearer. On the bottom, smoke from dozens of fires (left side of image) in China swirls down along valleys and then out over Bo Hai Bay (upper right) on its way towards Korea and the Pacific Ocean.
Credits: Images courtesy of Jacques Descloitres, MODIS Land Rapid Response Team, NASA GSFC. Text from UCAR’s page on aerosols here.
From Ascribe Newswire
COLLEGE PARK, Md, March 12 — A University of Maryland-led team has compiled the first decades-long database of aerosol measurements over land, making possible new research into how air pollution changes affect climate change.
Using this new database, the researchers show that clear sky visibility over land has decreased globally over the past 30 years, indicative of increases in aerosols, or airborne pollution. Their findings are published in the March 13 issue of Science.
“Creation of this database is a big step forward for researching long-term changes in air pollution and correlating these with climate change,” said Kaicun Wang, assistant research scientist in the University of Maryland’s department of geography and lead author of the paper. “And it is the first time we have gotten global long-term aerosol information over land to go with information already available on aerosol measurements over the world’s oceans.”
Wang, together with Shunlin Liang, a University of Maryland professor of geography, and Robert Dickinson, a professor of geological science at the University of Texas, Austin, created a database that includes visibility measurements taken from 1973 – 2007 at 3,250 meteorological stations all over the world and released by the National Climatic Data Center (NCDC). Visibility was the distance a meteorological observer could see clearly from the measurement source. The more aerosols present in the air, the shorter the visibility distance.
According to the researchers, the visibility data were compared to available satellite data (2000-2007), and found to be comparable as an indicator of aerosol concentration in the air. Thus, they conclude, the visibility data provide a valid source from which scientists can study correlations between air pollution and climate change.
Aerosols, Greenhouse Gases and Climate Change
Aerosols are solid particles or liquid droplets suspended in air. They include soot, dust and sulfur dioxide particles, and are what we commonly think of when we talk about air pollution. Aerosols come, for example, from the combustion of fossil fuels, industrial processes, and biomass burning of tropical rainforests. They can be hazardous to both human health and the environment.
Aerosol particles affect the Earth’s surface temperature by either reflecting light back into space, thus reducing solar radiation at Earth’s surface, or absorbing solar radiation, thus heating the atmosphere. The variable cooling and heating effects of aerosols also modify properties of cloud cover and rainfall.
Unlike aerosol particles, carbon dioxide and other greenhouse gases are transparent and have no effect on visibility. Sunlight passes right through them, just as it does through the oxygen and nitrogen that are the main constituents of our atmosphere. Though present in the atmosphere in relatively small amounts, greenhouse gases cause global warming because these “trace” gases trap solar energy absorbed at the earth’s surface and prevent it from being radiated as heat back into space.
While the climate warming impacts of increased greenhouse gases are clear, the effects of increased aerosols are not. Studies of the long-term effects of aerosols on climate change have been largely inconclusive up to now due to limited over-land aerosol measurements, according to Wang and his team. However, with this database researchers now can compare temperature, rainfall and cloud cover data from the past 35 years with the aerosol measurements in the new database.
Global Dimming
According to the authors, a preliminary analysis of the database measurements shows a steady increase in aerosols over the period from 1973 to 2007. Increased aerosols in the atmosphere block solar radiation from the earth’s surface, and have thus caused a net “global dimming.” The only region that does not show an increase in aerosols is Europe, which has actually experienced a “global brightening,” the authors say.
The largest known source of increased aerosols is increased burning of fossil fuels. And a major product of fossil fuel combustion is sulfur dioxide. Thus, the team notes, that their finding of a steady increase in aerosols in recent decades, also suggests an increase in sulfate aerosols. This differs from studies recently cited by the Intergovernmental Panel Climate Change showing global emissions of sulfate aerosol decreased between 1980 and 2000.
OK, we need a common glossary of terms.
Air pollution regulation focuses on HC and NOx as precursers of photochemical SMOG, and control of particulate matter of various sizes from 10 to 2.5. All of these air contaminants are byproducts of combustion. The SMOG portion is a photochemical cloud of very nasty byproducts resulting from atmospheric mixing of VOC/NOx in the presence of solar energy. As distinguished from SMOKE and its particulate-rich haze of partially burned materials.
Aerosols seems to be a much more inclusive term. Would someone care to set the table? Are we talking about SMOG, SMOKE, HAZE, MIST?
Isn’t it a shame that governments worldwide are gearing up and spending their resources to go after CO2 “pollution” rather than real pollution like PM, HC, Pb, low level O3 and so forth. There is technology to take care of these real pollutants as evidenced by the ever improving air quality in the US even if we do emit 25% of the worlds CO2. Ill take CO2 over criteria pollutants any day. At what point do those in India China and elsewhere in the developing world tell us to shove off because of our CO2 hysteria. While they are at it, they may also tell us to shove off with real pollutant control systems which would actually do some good.
Back in ’96 I sat in a Chinese bus with yellow ash falling on me from the nearby power plant in Jinan. When I came back to the US and to LA none the less I just couldn’t believe how clean our “dirty skies” are. Bring on the CO2… especially if it helps us clean up real pollution.
BTW Viva Anthony! This is a great site. Keep up the good work!
check out the link to UCAR below the pics. It gives a nice overview.
Moderators
I know this is OT, but I wanted to bring it to Anthony’s attention :
“Green Jobs Czar”
Obama appointment, 3/10/09 :
From the White House Blog :
http://www.whitehouse.gov/blog/09/03/10/Van-Jones-to-CEQ/
YouTube video of Van Jones on “The Third Wave of Environmentalism” :
YouTube video of speech from Van Jones at PoweShift 09 :
If i were president this kid would be my “Green Czar” ! 😉
YouTube video :
It would be ironic if climate scientists confirm that aerosols cause cooling. Encourage “global dimming” by burning more fossil fuels!
@ur momisugly Kath (21:14:08) :
I don’t think that they will ever promote that, the Greens won’t let them.
Everything is caused by C02.
Global Warming, Global Cooling, Global Dimming, Global Brightening.
Forget about takling the real pollutants, or the particulates, or the chemical spills, that is too easy.
Do something impossible.
Get stupid.
Yes, that’s the ticket.
Global Stupidity.
You’re getting sleepy…
Colorless, odorless, slight taste of acid.
Plants love it.
CO2 isn’t a greenhouse gas, it the gas the Green eats.
Plant food.
Now, why would you want to starve all plant life?
Tired of living is my guess.
So next time I want to increase the growth in my greenhouse, I should pop open a Coke or a Pepsi.
Let them pollute. At this point, increased affluence is saving and extending FAR more lives than are being lost to pollution. Give it a decade or three–they will have become affluent and that equation will have reversed itself. Then they’ll clean up in the same manner and for the same reasons in industrialized west did. For everything there is a season and a time for every purpose under heaven.
If they are coerced into signing any stupid treaty, I would heartily encourage them to violate it–ignore it completely. For the Children.
Everything is caused by C02.
“Everything
Everything
Everything gives you cancer
Everything gives you cancer
There’s no cure, there’s no answer”
Now wait a second. I’m no expert but haven’t I read at WUWT multi-numerously that aeroosols COOL, at least in the super-computed CC Models?
I’m sure I’ve read that aerosols are a counter-forcing negatory feedback factor, and in fact without them all the CCM’s would have blown up long ago. Why, if not for aerosols the world’s oceans would have boiled away in the Eocene, at least according to the mysterious CODE written in proto-Fortran that is the medulla oblongata of IPCC models.
Moreover, don’t volcanos spew forth gobs of aerosols? Haven’t biggish eruptions like Pinatubo cooled the globe rather emphatically, surmounting even the vaunted El Nino?
I feel sorry for those choking Bangladeshis, but don’t they understand that without those greasy brown aerosols they’d all be treading water?
I mean, if COOLING the planet is such a grand idea, so important that we bleed trillions in taxes in paganous symbolic gesture, why not air pollute like crazy instead? Fire up the teepee burners, fill the smokestacks, rip out the automobile catalytic converters and chuff, baby chuff?
Personally, I am in favor of warming the planet. I don’t see any upside to cooling this rock down. But that’s just me, iconclast and outre contrarian such as I am. Billions of huddled masses yearn for a cooler world, including the sagacious Political Elite. So give it to them. Particulate the airsheds today!
Unless aerosols warm the globe, too, as the article implies, or they might, or we just don’t know, or the CCM have it backasswards, or something is screwy in Denmark, or huh, whatever?
Let’s have it both ways. Why not?
Although the article above blames the burning of fossil fuels of aerosols, a recent study has showed that the major cause of brown cloud over Asia and India is caused by the burning of biomass.
http://www.sciam.com/podcast/episode.cfm?id=south-asia-brown-cloud-is-homemade-09-01-26
Silly naive question. (aha!) Why does the sky look blue when you look up, lightening the black night sky; but it doesn’t blue out the blackness of the oceans, even though it’s the same thickness?
Robert Bateman (21:53:38) :
Everything is caused by C02.
…
Do something impossible.
Get stupid.
Yes, that’s the ticket.
Global Stupidity.
You’re getting sleepy…
you have to have a party
when you’re in a state like this
you can really move it all
you have to vote and change
you have to get right out of it
like out of all this mess
you’ll say yeah to anything
if you believe all this but
don’t cry, don’t do anything
no lies, back in the government
no tears, party time is here again
president gas is up for president
line up, put your kisses down
say yeah, say yes again
stand up, there’s a head count
president gas on everything but roller skates
it’s sick the price of medicine
stand up, we’ll put you on your feet again
open up your eyes
just to check that you’re asleep again
president gas is president gas again
-Psychedelic Furs 1982-
atmospheric aerosols could either warm or cool the atmosphere depending upon the size, distribution and optical properties. Of all the climatic elements, temperature plays a major role in detecting climatic change brought about by urbanization and industrialization. This paper, therefore, attempts to study temporal variation in temperature over Pune city, India, during the period 1901–2000. The long-term change in temperature has been evaluated by Mann–Kendall rank statistics and linear trend. The analysis reveals significant decrease in mean annual and mean maximum temperature. This decrease in temperature is more pronounced during the winter season, which can be ascribed to a significant increase in the amount of suspended particulate matter (SPM) in the ambient air during the last decade. On the contrary, monsoon season shows warming. This warming can be attributed to a significant increase in the low cloud amount.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VH3-4H68T8S-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=10&md5=0419d93ad49cf24bdd1bb4a69bc7d2c9
BTW, temperature changes over the last 50 to 100 years seems linked to low cloud levels.
Global data showing temperature trends by humidity level may well be the ‘smoking gun’ for aerosols being the primary cause of the observed warming.
cite=”While the climate warming impacts of increased greenhouse gases are clear, the effects of increased aerosols are not.”>cite
Statement part 1, I think there might be a degree of disagreement with.
Part 2 should be interesting, we’ll have one side arguing that this means that once this pollution is cleared up (Naturally by taxing something or other), then we’ll have a planet resembling that shown in that great film “Waterworld” crossed with a sauna. The other side will say that we’ll have a somewhat extended skiing season.
“the researchers show that clear sky visibility over land has decreased globally” is a really lousy sample of English. It is utterly ambiguous because “globally” might mean “everywhere on the globe” [or approximately so] or it may be intended to mean “averaged over the globe”.
Just Want Truth… (21:03:57) :
I watched the vids. Oh my God, I feel sorry for those kids!
As to the post, I guess climate change has it covered. What’s
next: Up means down and right means left! All, and I mean
all of these people live in different reality. They are really
screwed up!
Lucy Skywalker (00:13:26) :
Silly naive question. (aha!) Why does the sky look blue when you look up, lightening the black night sky; but it doesn’t blue out the blackness of the oceans, even though it’s the same thickness?
I always thought that was to do with the way inbound light the atmosphere refracts through the scattering of molecules. My suggestion is lightning would be outbound light and perhaps is such a small source of light compared to the sun, the scattering effect of molecules is minimal. I have seen a lot of pictures of lightning where the outer fringes of the light are blue though. Here are some photo examples although they could be taken through filters;
one
two
three
four
five
From my experience in developing countries I wonder how much of these aerosols are due to fossil fuels and how much are due to burning wood and trash. In Nicaragua one of the reasons they cut down the rain forests is to get fuel to cook with, and the wood makes a lot of smoke. In Managua, since no one will haul away the trash, they burn it in the middle of the city on every street corner which probably isn’t good for the planet, and is certainly no fun to breathe. Burning fossil fuels cleanly to cook with and to properly dispose of the trash would be a great improvement.
I recall the great yellow cloud of muck wafting over the Pacific from Managua at twilight. Not a pleasant sight.
Philip_B (00:51:35) :
So smoke is the ‘smoking gun’ being the primary cause of the observed warming?
This new database, if confirmed will be built into the models now.
The models need to have the negative temperature impacts from factors such as Aerosols to keep them on track given the increase in temps they have built in for greenhouse gases.
Aerosols is the biggest negative temperature factor right now (given there has been no significant volcano for amost 18 years).
The model’s predictions will miss future temperature trends by a very large margin unless there is a big uptick in temps in the next few years or if they don’t find another big negative forcing to build in to offset the GHG components.
I haven’t seen this data yet but a bigger Aerosols impact than previously projected might be just be what the models need right now.
Here is GISS Model E “Aerosols” forcing versus temperature.
http://img175.imageshack.us/img175/6919/modeleaerosolshb4.png
Previously I posted about the 1940-1975 warming “pause” as perhaps being caused by air pollution.
link 1
Then I hypothesized that the “pause” we are experiencing now might be due to the industrialization of the Eastern world, China and India especially. I was told that the pollution in the East was “brown cloud” which is actually a warmer.
link 2
Brown Cloud pollution does not show up on IPCC forcing list as a positive forcing. Aerosols, in general, are listed as negative forcings. If Brown Cloud pollution is confirmed to be a positive forcing this will diminish the role of co2 as a warmer. The good news about Brown Cloud pollution, unlike co2, is that it can be addressed using proven technology long in use in the Western world and China and India will do this before they turn to trying to control co2.
“According to the authors, a preliminary analysis of the database measurements shows a steady increase in aerosols over the period from 1973 to 2007. Increased aerosols in the atmosphere block solar radiation from the earth’s surface, and have thus caused a net “global dimming.” The only region that does not show an increase in aerosols is Europe, which has actually experienced a “global brightening,” the authors say.” Europe agressively implemented clean air legislation to combat the acid rains and killer smogs (question: on this blog are we believing in acid rain and killer smog or is this another scam?). This is the reason Europe’s particulate production drop. At a guess Britains dash to gas and France extensive nuclear energy programs would be big factors in this.
Philip_B
Now the idea that sulphate pollution warms the world is a new one on me. 1815, Tamboda and all you see.