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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“Sounds like the same principle here only I learned this in grade school”
How about the principle in plant science known as photosynthesis that we all learned in biology or science class? Remember that, back in the old days when CO2 was a good guy.
Why do all these unproven theories get so much weighting/money/attention when something on ground as solid as gravity(the use of CO2 by plants to make their own food) gets brushed under the rug.
Increased CO2 is causing massive increases in plant growth, crop yields and world food production. http://www.co2science.org/data/plant_growth/dry/dry_subject.php
Cutting back on CO2 would be like a man barely making enough to feed his 10 kids being presented with a solution:
Cut back on your work hours because you’re making too much money!.
Is there something new with this? It has been long known that aerosols suck up VOCs, indeed that VOCs and SO2 play an important role in forming CCNs (the VOCs also are important for tropospheric ozone formation). An interesting recent paper showed that beyond 2 nm diameter the VOCs dominate while under 2nm, the SO2 concentration is limiting.
BTW, this sticks a fork into the CERN experiment if its point is to show that cosmic rays dominate the formation of CCNs.