From the University of Manchester
Organic vapors affect clouds leading to previously unidentified climate cooling
University of Manchester scientists, writing in the journal Nature Geoscience, have shown that natural emissions and manmade pollutants can both have an unexpected cooling effect on the world’s climate by making clouds brighter.
Clouds are made of water droplets, condensed on to tiny particles suspended in the air. When the air is humid enough, the particles swell into cloud droplets. It has been known for some decades that the number of these particles and their size control how bright the clouds appear from the top, controlling the efficiency with which clouds scatter sunlight back into space. A major challenge for climate science is to understand and quantify these effects which have a major impact in polluted regions.
The tiny seed particles can either be natural (for example, sea spray or dust) or manmade pollutants (from vehicle exhausts or industrial activity). These particles often contain a large amount of organic material and these compounds are quite volatile, so in warm conditions exist as a vapour (in much the same way as a perfume is liquid but gives off an aroma when it evaporates on warm skin).
The researchers found that the effect acts in reverse in the atmosphere as volatile organic compounds from pollution or from the biosphere evaporate and give off characteristic aromas, such as the pine smells from forest, but under moist cooler conditions where clouds form, the molecules prefer to be liquid and make larger particles that are more effective seeds for cloud droplets.
“We discovered that organic compounds such as those formed from forest emissions or from vehicle exhaust, affect the number of droplets in a cloud and hence its brightness, so affecting climate,” said study author Professor Gordon McFiggans, from the University of Manchester’s School of Earth, Atmospheric and Environmental Sciences.
“We developed a model and made predictions of a substantially enhanced number of cloud droplets from an atmospherically reasonable amount of organic gases.
“More cloud droplets lead to brighter cloud when viewed from above, reflecting more incoming sunlight. We did some calculations of the effects on climate and found that the cooling effect on global climate of the increase in cloud seed effectiveness is at least as great as the previously found entire uncertainty in the effect of pollution on clouds.”
The paper:
Nature Geoscience paper, ‘Cloud droplet number enhanced by co-condensation of organic papers,’ by Gordon McFiggans et al,
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But, but, but………didn’t we kind of ‘know’ this from ages ago? – i.e. that clouds reflect sunlight and ergo have a probable negative impact on temperature? The cloud seeding issue is just another ‘unkown’ – speculatively ‘modeled’ which is subsequently ‘improved’ by adding aerosol/pollutant ‘seeds’ in the model……..etc, etc……more ‘models all the way down’, methinks
“We discovered that organic compounds such as those formed from forest emissions or from vehicle exhaust, affect the number of droplets in a cloud and hence its brightness, so affecting climate”
Easy, forests should be regulated. Or even better, utterly destroyed to get rid of emissions once and for all.
Dave Wendt says:
As for the Sahara, a canal from the Med to the Qattara Depression would not only generate large amounts of hydro power, but would create a large salt lake, and evaporation from it would do a good job of greening a large part of the Sahara.
http://en.wikipedia.org/wiki/Qattara_Depression_Project
Richard Telford: your
“…the CO2-induced warming has been masked, and you can kiss goodbye to your low climate sensitivity.”
Possibly. But, natural VOCs from forests, both urban and rural, account for a larger percent of ozone precursors in cities like Toronto. These same compounds are likely to be the aerosols modeled in this paper.
As vegetation worldwide is up over 6% since 1980, and forests are now larger in North America than they have been for a 100 years, it is likely that any VOCs that affect cloud brightness, are likely to be natural in origin.
But, as this is a model, and not empirical data, I will remain skeptical of the results.
GlynnMhor says:
May 6, 2013 at 12:30 pm
“Yet some two thirds of the supposed CO2 warming in the AGW paradigm involves the formation and behaviour of clouds from water vapour.”
What “AGW paradigm” are you talking about. Certainly not the IPCC. JP
Philip Bradley says:
May 6, 2013 at 1:52 pm
The opposite is true. Pollution levels have declined substantially in most of the world over the last 4 or 5 decades.
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I guess you have never been to China or India. Sulphate loading is flat since about 1975, not substantially declining.
http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
>>Questions I have: Can anyone point to data showing a general global rise in cloud cover? Can anyone point to data explaining the global rise in temperatures in the presence of this increasing cloud cover?
Google
http://www.drroyspencer.com cloud cover
He has a number of posts that address cloud cover.
esp this post that correlates the PDO with changes in global cloud cover
http://www.drroyspencer.com/research-articles/global-warming-as-a-natural-response/
at the bottom of that article are also links to papers he wrote regarding this relationship
Smoky mountains, USA, = Blue Mountains,NSW, 50+ miles west of Sydney. A beautiful area and a similar reason for the blue haze but eucalyptus trees and their oily emissions.
peterg says:
May 6, 2013 at 3:15 pm
“How hot would it be without clouds?”
Clouds are inextricably linked to water vapor. Without either, it would be about -16^C. JP
Berényi Péter says:
May 6, 2013 at 3:56 pm
“Easy, forests should be regulated. Or even better, utterly destroyed to get rid of emissions once and for all.”
Why would we want to”destroy” a temperature modulator? JP
Duster says:
“You want to remember that all science starts out as speculation. Some philosophers of science such as Karl Popper and Carl Hempel rejected the idea that development of explanatory ideas concerning scientific problems was even part of science.”
Never heard of Mr. Hempel, but are you sure you are not mistaking Karl Popper for someone else? Popper asserted that all scientific knowledge is, and always remains, hypothesis. In contrast to the fashion of the day, which sought the recipe for extorting theories from facts by some sort of distillation, Popper emphasized that science always starts with, and is guided by, hypotheses.
This world seems to have a well-designed climate system with self-correcting mechanisms built into it. Who would have guessed?
I hate being sarcastic but I was told that the science was settled. We MUST act now! Imagine the known unknowns and the unknown unknowns.
If ever there was an area of serious scientific dispute and controversy it is Climate Science at No. 1. It’s never settled.
So … The Clean Air Act is the US and UK and a bunch of other industrial nations would have have created cleaner air which would resulting warming?
From the 1980s on or so ….
Is it me or has the text font changed? Please advise.
[Check your ctrl+scroll wheel setting. No change on WUWT. Mod.]
This is not on. Climate scientists make PROJECTIONS not ” predictions“. Sheesh! & LOL.
richard telford says:
May 6, 2013 at 4:08 pm
I guess you have never been to China or India. Sulphate loading is flat since about 1975, not substantially declining.
http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
What Tamino says is,
They find (as do previous studies) rapid increase in sulfate emissions from mid-century until about 1975-1980, followed by a decline in emissions.
Please don’t misrepresent a source, and I noted there are exceptions to the general global reductions in anthropogenic aerosols, specifically mentioning India. I could go on, reductions in atmospheric nitrogen compounds from the use of catalytic converters that exactly coincides with the start of the mid-1970s warming, etc.
What I find fascinating, is that a couple of years ago, the “Team” would have squashed publication of a paper like this. Or the would have forced it the be published in a minor journal.
We are now seeing many more papers than ever I can remember, that do not reinforce the “consensus”. I suspect / hope that we are evolving from post normal science back to normal science. Although, I fear it will take a while yet.
Regards
/ikh
@AlecM
What was van der Hulst’s mistake? If true this affects some of my work, I really would like to know.
The UK is now climate quackology central. On one hand you have dumbed down group thinking in academia and on the other you have the greenfleecing Royal family sucking the lifeblood out of the once renowned Royal Society.
Is there any historical global pollution data that could be used to see if there is any correlation with clouds? I was also pointed to http://wattsupwiththat.com/2012/08/20/spencers-cloud-hypothesis-confirmed/ This paper referenced looked at reasons for cloud distributions over only the last 39 years. It does not tie the formations to global warming except through statements like; “The declines in total cloud cover seen at middle latitudes and the increases in the Arctic agree with recent predictions by global climate models given greenhouse warming.” The article also talks about aerosols/clouds as if they are are an already known process, albeit not completely known. It seems to me that the title of this WATT article “another global cooling mechanism found…” is misleading. It is already known and is in the models to some level of accuracy. Further, what about before the Clean Air Act and into the 1800s when it was even cooler?
Berényi Péter says:
May 6, 2013 at 3:56 pm
“We discovered that organic compounds such as those formed from forest emissions or from vehicle exhaust, affect the number of droplets in a cloud and hence its brightness, so affecting climate”
Easy, forests should be regulated. Or even better, utterly destroyed to get rid of emissions once and for all.
———————————
There you go forgetting about the unintended consequences.
Where we gonna get Christmas trees?
cn
http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
The first law in climate science! Any changes of climate must be caused by changes internal to the Earth, preferable caused by man and can not be attributed the object outside the Earth such as the Sun or the Moon. Therefore any failed prediction has to have a new or re-circulated Earth based cause. The heat has escaped to the depth of the oceans, [recent] cooling is caused by Chinese smokestacks, cooling is caused by the warm Arctic or organic compounds from plants is cooling the Earth.
Um, no.
“affect the number of droplets” … “affecting climate”… “We developed a model and made predictions” … “atmospherically reasonable” … .
Nonsense!
“Climate Alchemy ” [AlecM]
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Hey, Jimbo! This dovetails nicely with your excellent ship to submarine (now looking for AGW in the deep oceans) “Ding! ding!” LOL metaphor (on the I-can’t-remember-thread recently).
Hansen: [looking out sub porthole into the murky depths] Ah, this is more like it, Cook! That water is mighty warm; our supersensitive crackdiddly magnificent CO2 detection decoder (a.k.a. thermometer) says that the ocean is a whopping 68 degrees F! That’s a LOT more than we expected. It MUST BE —
Cook: [high five’s H.] C– O — 2!
SubCommander [under contract, not part of The Team — as if they could!]: Mr. Hansen, sir, (cough), we are at a depth of 20 feet. Water’s pretty warm this time of year in Florida.
Hansen: Oh [frowny face]……………………… [brightens] — clouds!
[Next scene: Hansen and Cook getting into a tiny airplane, the (non-Team) pilot looking highly dubious makes sure he is paid in advance.]
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Re: font — I haven’t detected a change — MUST mean there isn’t one, LOL.