Recall a couple of days ago that I posted on the aerosols released by trees: Those dirty trees: why hasn’t the EPA called for trees to be regulated?
Now, from the International Institute for Applied Systems Analysis comes a cause-effect for climate.
Plants moderate climate warming
As temperatures warm, plants release gases that help form clouds and cool the atmosphere, according to research from IIASA and the University of Helsinki.
The new study, published in Nature Geoscience, identified a negative feedback loop in which higher temperatures lead to an increase in concentrations of natural aerosols that have a cooling effect on the atmosphere.
“Plants, by reacting to changes in temperature, also moderate these changes,” says IIASA and University of Helsinki researcher Pauli Paasonen, who led the study.
Scientists had known that some aerosols – particles that float in the atmosphere – cool the climate as they reflect sunlight and form cloud droplets, which reflect sunlight efficiently. Aerosol particles come from many sources, including human emissions. But the effect of so-called biogenic aerosol – particulate matter that originates from plants – had been less well understood. Plants release gases that, after atmospheric oxidation, tend to stick to aerosol particles, growing them into the larger-sized particles that reflect sunlight and also serve as the basis for cloud droplets. The new study showed that as temperatures warm and plants consequently release more of these gases, the concentrations of particles active in cloud formation increase.
“Everyone knows the scent of the forest,” says Ari Asmi, University of Helsinki researcher who also worked on the study. “That scent is made up of these gases.” While previous research had predicted the feedback effect, until now nobody had been able to prove its existence except for case studies limited to single sites and short time periods. The new study showed that the effect occurs over the long-term in continental size scales.
The effect of enhanced plant gas emissions on climate is small on a global scale – only countering approximately 1 percent of climate warming, the study suggested. “This does not save us from climate warming,” says Paasonen. However, he says, “Aerosol effects on climate are one of the main uncertainties in climate models. Understanding this mechanism could help us reduce those uncertainties and make the models better.”
The study also showed that the effect was much larger on a regional scale, counteracting possibly up to 30% of warming in more rural, forested areas where anthropogenic emissions of aerosols were much lower in comparison to the natural aerosols. That means that especially in places like Finland, Siberia, and Canada this feedback loop may reduce warming substantially.
The researchers collected data at 11 different sites around the world, measuring the concentrations of aerosol particles in the atmosphere, along with the concentrations of plant gases, the temperature, and reanalysis estimates for the height of the boundary layer, which turned out to be a key variable. The boundary layer refers to the layer of air closest to the Earth, in which gases and particles mix effectively. The height of that layer changes with weather. Paasonen says, “One of the reasons that this phenomenon was not discovered earlier was because these estimates for boundary layer height are very difficult to do. Only recently have the reanalysis estimates been improved to where they can be taken as representative of reality.”
Reference
Paasonen, P., et. al. 2013. Evidence for negative climate feedback: warming increases aerosol number concentrations. Nature Geoscience doi: 10.1038/NGEO1800
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Just when they were planning to cut down all the trees to save the planet…
Heh, negative feedbacks in nature. Whatever next.
Was taught this in F.F.A. back in the sixty’s , and now it’s headlines ?
“The study also showed that the effect was much larger on a regional scale, counteracting possibly up to 30% of warming in more rural, forested areas where anthropogenic emissions of aerosols were much lower in comparison to the natural aerosols. That means that especially in places like Finland, Siberia, and Canada this feedback loop may reduce warming substantially.”
Aerosols act locally not globally. Cool. As our understanding of influences on climate increases, maybe in a hundred years or so we will know where to locate the thermometers. Better yet, maybe we will a list of influences that are factored into each thermometer reading.
And that’s not all they didn’t know they didn’t know about the world
This means the warming of 1900-2000 might pretty well be manmade – through global deforestation and cutting off the running negative temperature feedback.
Like “The Economist” reported in March, temperature has flat-lined for 15 years … now we know why.
I thought this was well known decades ago.
It is part of the reason I have said many times that there are plenty of aerosols already in the atmosphere such that the Svensmark theory about more clouds from more cosmic rays is unlikely.
It is also known that changes in micro organisms in the oceans can change the amount of aerosols in the air above.
No joined up knowledge in climate science apparently.
Just thousands of over narrow specialists constantly reinventing the wheel.
Yes, it is still a bad idea to cut down the rainforests of Borneo to make biofuel.
The IIASA and the University of Helsinki got it right; forests cool the ground they are in.
I still remember back several years ago when the EPA recommended that Atlanta cut down its trees in order to reduce smog and meet the clean air standards at the time, even though the Blue Ridge Mountains couldn’t meet them. I kept waiting for them to suggest clear cutting the Blue Ridges.
There’s also another negative feedback consider when more CO2 increases leading to more plant life. When Carbon Dioxide Increases, it allows for plants to grow more, and withdraw more Carbon Dioxide from the atmosphere, thus providing a negative feedback.
So global warming is still influenced by man – deforestation remains a problem.
The equation involving photosynthesis is:
sunlight + water + carbon dioxide —> glucose + oxygen.
So if more of the sun’s energy goes into photosynthesis, then less is available to heat up the atmosphere.
Hopefully all this late season snow will melt so the farmers can plant crops to save us
The effect of enhanced plant gas emissions on climate is small on a global scale – only countering approximately 1 percent of climate warming, the study suggested.
>>>>>>>>>>>>>>>>>>>
Well let’s do some quick math based on the CAGW meme.
Doubling CO2 = 3.7 w/m2
Water vapour feedback = 7.4 w/m2
Total = 11.1 w/m2.
At levels of CO2 40% above “background”, and the effect being logarithmic, let;s call it 50% of the effect is currently in place. 11.1 x 0.5 = 5.55 w/m2.
1% of which would be 0.0555 w/m2.
So they detected a difference due to plant based aerosols that could be accurately differentiated from all other aerosols (which they state in the paper are poorly understood!) and they measured it to be 5 one hundredths of 1 w/m2?
LOL
lenbilen says:
April 28, 2013 at 2:03 pm
“Yes, it is still a bad idea to cut down the rainforests of Borneo to make biofuel.”
Matt Ridley recently pointed out that fossil fuels are what the Green movement should want; as we don’t compete with plants or animals for resources when we use fossil fuels.
“No animal eats coal”
http://wattsupwiththat.com/2013/03/14/a-must-watch-greening-the-planet-dr-matt-ridley/#more-82153
If the Green movement were not the shocktroops of the Club of Rome, that is…
“The common enemy of humanity is man. In searching for a new enemy to unite us, we came up with the idea that pollution, the threat of global warming, water shortages, famine and the like would fit the bill. All these dangers are caused by human intervention, and it is only through changed attitudes and behavior that they can be overcome. The real enemy then, is humanity itself.”
– Club of Rome
Robber says:
April 28, 2013 at 2:42 pm
So global warming is still influenced by man – deforestation remains a problem.
Yes I agree, loss of vegetation is a real environmental / ecological problem. CO2 increase on the other hand actually mitigates the problem of vegetation loss by making the remaining vegetation photosynthesise more vigorously. As this realisation sinks in the truly enormous scale of the fallacy of CAGW will become apparent. We need as much vegetative cover as possible and as much CO2 as possible as well (dont pave over your garden!)
Fortunately every human being requires the existence of several acres / hectares (dont know what area exactly) of plant food production to keep him / her alive, this fact will limit the extent to which population growth will reduce vegetative cover. Plus if forest is cleared for agriculture, i.e. plants especially monocotyledon grasses like wheat, then these plants can actually photosynthesise more efficiently (with 4 photosynthesis) than the equivanent C3 tree cover.
I thought the “science” was already settled. It isn’t? My, my, my… What a surprise!
” While previous research had predicted the feedback effect, until now nobody had been able to prove its existence except for case studies limited to single sites and short time periods. The new study showed that the effect occurs over the long-term in continental size scales.”
so yes some of you folks ( see Wilde) may have been taught this before.
like good skeptics they didnt swallow the koolaid as some here perhaps did. they went out to prove it.
Funny.
Werner Brozek says:
April 28, 2013 at 3:12 pm
The equation involving photosynthesis is:
sunlight + water + carbon dioxide —> glucose + oxygen.
So if more of the sun’s energy goes into photosynthesis, then less is available to heat up the atmosphere.
First the earth’s surface was mostly rock. Then snowball earth ice ages lasting tens of millions of years ground much of the surface rock to dry powder. Later, plants (having evolved and spread on land) turned these “weathered silicates” into moist, humic soils. In doing so they locked water on previously arid land. The earth got quite a lot cooler around that time (Silurian-Devonian-Carboniferous).
The ways plants cool the earth are:
– maintaining humic soil this locking water on (otherwise arid) land
– transpiration of water from these soils (that they have created) to the atmosphere via woody roots and stems and leaf stomata
– in this way sustaining the hydrological cycle over land
– darkening of the surface thus decrease in albedo
2-methyl-1,3-butadiene (Isoprene).
To their credit, the IPCC has managed to mention it, but I suspect that it’s effects may have been underestimated.
Whether the EPA could forgive trees for emitting so much of it remains to be seen.
Stephen Wilde says:
April 28, 2013 at 1:49 pm
I thought this was well known decades ago.
It is part of the reason I have said many times that there are plenty of aerosols already in the atmosphere such that the Svensmark theory about more clouds from more cosmic rays is unlikely.
It is also known that changes in micro organisms in the oceans can change the amount of aerosols in the air above.
No joined up knowledge in climate science apparently.
Just thousands of over narrow specialists constantly reinventing the wheel.
You’re dead right. Real scientists are driven to learn the complexity and wonder of the natural world as an interacting system of many parts. However, rent-seeking politically driven scientists like Steve Mosher wonder into a research field like this stoned out of their heads in delirious haze of mystical necrophilia, ignoring the complexity and multi-facetedness of nature and seeking only a mono-topic story of some death-particle which can be blamed on bipedal apes, hanging like a sword of Damocles over the biosphere, avoidable only by granting them money and political power. A very effective modern day shamanism. Maybe its time for them – and the masses who have piously and blindly followed them – to wake up and smell the coffee.
Abstract from above paper.
Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. Apart from black carbon aerosol, aerosols cause a negative radiative forcing at the top of the atmosphere and substantially mitigate the warming caused by greenhouse gases. In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect. Natural aerosols, too, might affect future warming. Here we analyse long-term observations of concentrations and compositions of aerosol particles and their biogenic precursor vapours in continental mid – and high – latitude environments. We use measurements of particle number size distribution together with boundary layer heights derived from reanalysis data to show that the boundary layer burden of cloud condensation nuclei increases exponentially with temperature. Our results confirm a negative feedback mechanism between the continental biosphere, aerosols and climate: aerosol cooling effects are strengthened by rising biogenic organic vapour emissions in response to warming, which in turn enhance condensation on particles and their growth to the size of cloud condensation nuclei. This natural growth mechanism produces roughly 50% of particles at the size of cloud condensation nuclei across Europe. We conclude that biosphere – atmosphere interactions are crucial for aerosol climate effects and can significantly influence the effects of anthropogenic aerosol emission controls, both on climate and air quality.
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1800.html
Supplementary Information (1.32MB PDF)
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1800.html
Oops….wrong abstract link….sorry… 🙂
http://www.nature.com/ngeo/journal/vaop/ncurrent/extref/ngeo1800-s1.pdf