From the University of Maryland Rising air pollution worsens drought, flooding, UMD-led study shows
COLLEGE PARK, Md. – Increases in air pollution and other particulate matter in the atmosphere can strongly affect cloud development in ways that reduce precipitation in dry regions or seasons, while increasing rain, snowfall and the intensity of severe storms in wet regions or seasons, says a new study by a University of Maryland-led team of researchers.
The research provides the first clear evidence of how aerosols — soot, dust and other small particles in the atmosphere — can affect weather and climate; and the findings have important economic and water resource implications for regions across the United States and around the world, say the researchers and other scientists.
“Using a 10-year dataset of extensive atmosphere measurements from the U.S. Southern Great Plains research facility in Oklahoma [run by the Department of Energy’s Atmospheric Radiation Measurement program] — we have uncovered, for the first time, the long-term, net impact of aerosols on cloud height and thickness, and the resultant changes in precipitation frequency and intensity,” says Zhanqing Li, a professor of atmospheric and oceanic science at Maryland and lead author of the study.
The scientists obtained additional support for these findings with matching results obtained using a cloud-resolving computer model. The study by Li and co-authors Feng Niu and Yanni Ding, also of the University of Maryland; Jiwen Fan of Pacific Northwest National Laboratory; Yangang Liu of Brookhaven National Laboratory, Upton, NY; and Daniel Rosenfeld of The Hebrew University of Jerusalem, is published in the Nov. 13 in Nature Geoscience.
“These new findings of long-term impacts, which we made using regional ground measurements, also are consistent with different findings we obtained from an analysis of NASA’s global satellite products and have just published in a separate study. Together, they attest to the needs of tackling both climate and environmental changes that matter so much to our daily life,” says Maryland’s Li, who is also affiliated with Beijing Normal University.”
“Our findings have significant policy implications for sustainable development and water resources, especially for those developing regions susceptible to extreme events such as drought and flood. Increases in manufacturing, building of power plants and other industrial developments are often accompanied with increases in pollution whose adverse impacts on weather and climate, as revealed in this study, can undercut economic gains,” he stresses.
Tony Busalacchi, chair of the Joint Scientific Committee, World Climate Research Program notes the significance of the new findings. “Understanding interactions across clouds, aerosols, and precipitation is one of the grand challenges for climate research in the decade ahead, as identified in a recent major world climate conference. Findings of this study represent a significant advance in our understanding of such processes with significant implications for both climate science and sustainable development,” says Busalacchi, who also is professor and director of the University of Maryland Earth System Science Interdisciplinary Center.
“We have known for a long time that aerosols impact both the heating and phase changes [condensing, freezing] of clouds and can either inhibit or intensify clouds and precipitation,” says Russell Dickerson, a professor of atmospheric and oceanic science at Maryland. “What we have not been able to determine, until now, is the net effect. This study by Li and his colleagues shows that fine particulate matter, mostly from air pollution, impedes gentle rains while exacerbating severe storms. It adds urgency to the need to control sulfur, nitrogen, and hydrocarbon emissions.”
According to climate scientist Steve Ghan of the Pacific Northwest National Laboratory, “This work confirms what previous cloud modeling studies had suggested, that although clouds are influenced by many factors, increasing aerosols enhance the variability of precipitation, suppressing it when precipitation is light and intensifying it when it is strong. This complex influence is completely missing from climate models, casting doubt on their ability to simulate the response of precipitation to changes in aerosol pollution.”
Aerosol Science
Aerosols are tiny solid particles or liquid particles suspended in air. They include soot, dust and sulfate 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 and agricultural processes, and the accidental or deliberate burning of fields and forests. They can be hazardous to both human health and the environment.
Aerosol particles also 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. This variable cooling and heating is, in part, how aerosols modify atmospheric stability that dictates atmospheric vertical motion and cloud formation. Aerosols also affect cloud microphysics because the serve as nuclei around which water droplets or ice particles form. Both processes can affect cloud properties and rainfall. Different processes may work in harmony or offset each other, leading to a complex yet inconclusive interpretation of their long-term net effect.
Greenhouse gases and aerosol particles are two major agents dictating climate change. The mechanisms of climate warming impacts of increased greenhouse gases are clear (they prevent solar energy that has been absorbed by the earth’s surface from being radiated as heat back into space), but the climate effects of increased aerosols are much less certain. Until now, studies of the long-term effects of aerosols on climate change have been largely lacking and inconclusive because their mechanisms are much more sophisticated, variable, and tangled with meteorology.
“This study demonstrates the importance and value of keeping a long record of continuous and comprehensive measurements such as the highly instrumented (ARM) sites run by the Department of Energy’s Office of Science, including the Southern Great Plains site, to identify and quantify important roles of aerosols in climate processes,” says Stephen E. Schwartz, a scientist at Brookhaven National Laboratory. “While the mechanisms for some of these effects remain uncertain, the well-defined relationships discovered here clearly demonstrate the significance of the effects. Developing this understanding to represent the controlling processes in models remains a future challenge, but this study clearly points in important directions.”
###
Support for this research was provided by the Department of Energy, NASA, the National Science Foundation and the Chinese Ministry of Science and Technology.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Why is it that any study that shows warming or alarmism only needs 10 years of data, but if it shows cooling or non alarmism 10 years isn’t good enough and 17 years is required.
At least this study says biofuels aren’t going to make a bit of difference (same pollution as any other carbon based fuel).
Two things:
Well, could I see some data, you know, to back it up? Maybe something showing how much and under what conditions with what kind of aerosols.
And, if this is true, we should see a lot of this going on in China right now, do we?
“We have known for a long time that aerosols impact both the heating and phase changes [condensing, freezing] of clouds and can either inhibit or intensify clouds and precipitation,”
Ah, the sulfurous smell of Chinese communist propaganda in the morning! So just like CO2 can cause both hot and cold, aerosols can cause more rain and less rain. I smell a model-based study into which some token data have been stuffed, inverted, adjusted, homogenized, tortured, then vomited out as a political paper, not science.
One interesting thing about aerosols is they give the same mid-troposphere warming signature as GHGs, but while GHGs warm the troposphere by impeding heat loss upward thus warming the climate, aerosols imped heat gain downward by blocking solar irradiance, thus cooling the climate.
The models attribute pretty much all the tropospheric warming to GHGs. I’m reasonably sure aerosols cause a large portion of it. And tropospheric warming is as much a signature of climate cooling as it is of climate warming.
The Botswana Gazette, 09 November 2011:
[ http://www.gazettebw.com/index.php?option=com_content&view=article&id=11848:botswana-talks-global-warming&catid=18:headlines&Itemid=2 ]
Ordinary folks puzzled
“Don’t you know that scientists lie a lot to make money?
I don’t believe them when they tell us that there is global warming because of emissions from fire or burning coal.
What I know is that when smoke goes up the sky it triggers rainfall and that is what we need in this country.”
These were the words of the unemployed Mothusi Songa as he sat alone in front of his shack in Old Naledi when The Gazette visited the area.
Songa does not believe that the recent heat waves were due to global warming because Botswana has always been a hot country thus to him an extra hot day is not a surprise.”
(via Luboš Motl)
[ http://motls.blogspot.com/2011/11/science-climate-sensitivity-is-17-26-c.html ]
Not mentioned is the major source of aerosols- the oceans surface. But that would be omitted because fossil fuel burning is their target.
But, but, but the models…
If I see one more paper based upon models I am going to puke. Somebody get me a bucket!
I was looking for the money maker and was not disappointed, “Greenhouse gases and aerosol particles are two major agents dictating climate change. “
So if we reduce pollution this will solve the droughts and flooding rains. If they succeed here in Australia then we will definitely have climate change.
I don’t know whether to take this post seriously or not.
Does that mean that all began in the 70s/80s with the common introduction of catalytic converters and (soot, but not only) filters of any kind, powered by the Green & Clean act?
Lesser aerosols and particles mean lesser precip and therefore lesser cooling?
That would also correlate with the starting point of the temperature incline since that date.
Did this come from their marketing department?
How did Daniel Rosenfeld got into the Asian Cloud Gang?
Lower level pollutants, who woulda thunk it? Has anyone checked to see if anyone involved with the IPCC stayed awake in thermo 101? Oh, that’s not required in liberal arts.
Lesser aerosols and particles mean lesser precip and therefore lesser cooling?
I doubt there is much of a precipitation effect. All water vapour in the atmosphere eventually ends up as precipitation somewhere.
It’s how long water vapour hangs around in the atmosphere that matters, when it forms clouds, and what kind of clouds.
The key effect IMO is that aerosol induced clouds have smaller droplet size and more reflective of solar radiation, Thus cooling the climate.
Otherwise your are correct, less aerosols,means fewer clouds and more solar insolation, warming the climate.
They don’t know where the aerosols come from. They assume from industrial activity. In green-speak, that’s bad.
They don’t know what effect aerosols have on climate. They could do just about anything. Whatever they do (less rain in dry areas, severe rain in wet areas, etc) appears to be bad.
They didn’t study greenhouse gases at all, yet state that increasing them will warm the planet, and in spite of the obvious benefits of a warmer planet they make it sound bad.
They state that increased industrialisation causes side effects which undercut economic gains, ie. bad effects. I don’t suppose for a moment that they actually quantified those side effects or even made the slightest attempt to.
Why do all these papers try to make out that everything isbad?
NB. Rhetorical question, don’t bother to reply, I know the answer perfectly well. It is “If we want a good environmental policy in the future, we’ll have to have a disaster.” – Sir John Houghton.
Please note that I have not quoted the better-known “unless we announce disasters, no-one will listen” because Sir John has stated categorically “I have never said that. … [they] say it comes from the first edition of my global warming book … It does not appear in that book in any shape or form.“. http://news.bbc.co.uk/2/hi/uk_news/wales/8511780.stm
However, before you start thinking that Sir John has been badly misrepresented, note the qualifier “in that book“. The better-known misquote has, it seems, morphed from the quote that I did use, which was indeed said by Sir John according to http://rabett.blogspot.com/2010/02/defining-denial-down_17.html
So it seems that Sir John has in fact said it in some shape or form, it’s just that he didn’t say it “in that book“. So why does he protest so vehemently? (Rhetorical again).
Maybe I should have used “The threat of environmental crisis will be the ‘international disaster key’ that will unlock the New World Order.” Mikhail Gorbachev. Nah, I’ll stick with Sir John’s rare moment of honesty, it has more ‘punch’.
“All water vapour in the atmosphere eventually ends up as precipitation somewhere.”
Well….but wait, not locally, way too many aerosols and particles create things like the self-feeding Dust Bowl of the ’30’s. With that many particles you would think it would be flooding but instead there was NO rain. That dust turned the skies of Chicago and D.C. red all the way from the Texas panhandle and Colorado. Read up on it. So, too much can in fact also bad for any droplets forming never get large enough to even fall, there are too many tiny droplets instead of a less number of big ones heavy enough to drop. I wouldn’t blow off such a paper at first glance. (and I have not even read it yet, but have read some history)
Don’t oceans cover 75% of our planet? As such, the oceans would not qualify as dry regions. The net effect of increased aerosols over the planet would then have to be an increase in “rain, snowfall and the intensity of severe storms.”
John M Reynolds
a) It’s a model! Simulations, representations, & sophisticated, etc,
b) too many mays, cans, could be, etc, with just as likely may nots, can nots, & could nots etc!
Oh well I exepcet the cheque was in the post any how! 🙂
Don’t know how it affected rainfall amounts on the plains of Spain, but it was widely noted during the American Civil War that major battles — which filled the air with particulates — were frequently followed by major deluges.
“Aerosol particles also affect the Earth’s surface temperature…….// Different processes MAY work in harmony or offset each other, leading to a complex yet INCONCLUSIVE interpretation of their long term net effect”
In other words, the models do not tell us what the net effect is, or even if it is in one direction.
But if you give us more money we will do some more research.
Aerosols come from many natural sources..eg. pine trees emit terpenes which degrade into fine aerosols and increase local cloud formation over pine forests, and as mentioned above, open water also produces aerosols. Not to mention dust storms and pollen and so on. It would be interesting to be able to compare times of high human aerosol production ( ie. pre clean air act legislation) with this (statistically short) data sample.
“Increases in manufacturing, building of power plants and other industrial developments are often accompanied with increases in pollution whose adverse impacts on weather and climate, as revealed in this study, can undercut economic gains,” he stresses.”
This shows the agenda of the Watermelons. They are anti-development and anti-energy. Notice the wiggle word “often”. The supreme irony is that their very own anti-carbon policies have simply forced many industries to China and other developing countries, where pollution controls are far less stringent. Only in the land of Water (melon) World are all power plants and industrial devolpments the same worldwide, no matter what country they are in.
Gary Mount says:
November 14, 2011 at 12:33 am
Why is it that any study that shows warming or alarmism only needs 10 years of data, but if it shows cooling or non alarmism 10 years isn’t good enough and 17 years is required.
At least this study says biofuels aren’t going to make a bit of difference (same pollution as any other carbon based fuel).
_____________________________________
Darn you beat me to it.
Why is 10 years good enough??? Because they used COMPUTER MODELS! Oh and also because they need the study for added ammo at Durbin since Kyoto Protocol ends December 2011.
That chap from Botswana was right. Years ago, before stubble-burning was made illegal (in UK), I was crossing Salisbury Plain, where stubble-burning was in progress. A|t the top of each column of smoke clouds were forming, some of them big, and very stormy-looking. Just an observation, no modelling, so no funding.
Anthea
I don’t remember these impacts in the 60’s and 70’s when I was growing up. In fact I remember pretty good growing seasons with adequate rainfall and a kind of hazy brownish blue sky from all the aerosols . I think someone is experiencing a very large case of expectation bias in this study, otherwise known as “I programed a computer to find what I wanted it to find!”
*****
Increases in air pollution and other particulate matter in the atmosphere can strongly affect cloud development in ways that reduce precipitation in dry regions or seasons, while increasing rain, snowfall and the intensity of severe storms in wet regions or seasons, says a new study by a University of Maryland-led team of researchers.
*****
The presence/absence of water does that anyway, on land at least. Wet regions evaporate water into vapor, which is lighter than typical air. Dry areas don’t evaporate as much. So wet areas favor upward convection (& resulting precip) at the expense of adjacent dry regions where sinking air is favored — adjacent wet & dry areas tend to reinforce each other. Tropical storms can disrupt the effect, tho.
You don’t need “Increases in air pollution and other particulate matter in the atmosphere” to cause the “wet begets wet & dry begets dry” effect on land.