Another negative climate feedback: more CO2 = more plants = more aerosols = cooling

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

===========================================================

66 thoughts on “Another negative climate feedback: more CO2 = more plants = more aerosols = cooling

  1. “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.

  2. This means the warming of 1900-2000 might pretty well be manmade – through global deforestation and cutting off the running negative temperature feedback.

  3. Like “The Economist” reported in March, temperature has flat-lined for 15 years … now we know why.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. I thought the “science” was already settled. It isn’t? My, my, my… What a surprise!

  12. ” 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. “…and Canada this feedback loop may reduce warming substantially.”
    Noooooooooooooooooo! I’m curious about the 1%. Is it 1% of the IPCC models and thus more than 1% of lukewarming? If the models are 3 degrees and the reality is 1 degree then it would be 3%?

  18. The KEY here is that this is IIASA. The IIASA constellation of RusComs and american lefty academics started this mess in 1978 with the infamaous Laxenberg report (which paved the way for the IPCC) in order to further their agenda-driven visions, and now their progeny see the writing on the wall and are trying for the graceful exit in order to preserve some type of credibility for their next apocalypse. That would be “ocean acidification”

    Agree/disagree?

  19. 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…
    Interesting that the warmists just happened to have shut out a whole slew of rural temperature gauges (circa 1993) in their move to overemphasize urban temperature stations. Hmm…

  20. phlogiston says
    “However, rent-seeking politically driven scientists like Steve Mosher ”

    I thought SM was a “Social scientist” and writer. ie NOT a scientist at all.

  21. Steven Mosher says:
    April 28, 2013 at 3:37 pm

    “like good skeptics they didnt swallow the koolaid as some here perhaps did. they went out to prove it.”

    How is that empirical work (by mainstream climate scientists) coming on cloud formation?

    How is that empirical work (by mainstream climate scientists) coming on water vapor and the hot spot?

    How is that empirical work (by mainstream climate scientists) coming on ENSO? Oh, I forgot, you told us that ENSO is not part of the natural world. ROTFLMAO! What are the empirical conditions that immediately precede cold water upwelling near the West coast of South America? How many guys are down there working on that?

    To be continued…indefinitely long…

    By the way, empirical science confirms or disconfirms hypotheses but proves nothing.

  22. Pat Michaels says:
    April 28, 2013 at 5:35 pm

    I agree that most are Commies. Watermelons. I agree that ocean acidification will get a big push.

  23. This hypothesis looks like an adaptation of Charlson’s hypothesis in which phytoplankton (in the ocean) emits dimethylsulfide (DMS) which then reacts to form a sulfate which serve as cloud condensation nuclei (to form clouds). This was one of the negative feedback mechanisms for “justifying” Lovelock’s Gaia hypothesis. See, Charlson, R.J. Lovelock, J.E., Andreae, M.O., and Warren, S.G. 1987. Oceanic phytoplankton, atmospheric sulfur, cloud albedo and climate: a geophysiological feedback. Nature 326;655-661.

    The major difference seems to be that this is developed for land (as opposed to ocean).

  24. I’ve heard that the acidification studies showing shells not developing alter ph by adding acid in, while the ones that have seen the animals grow much bigger did a direct study of elevated CO2 which takes much longer to work through the system, hence the acid shortcut. It seems like any acidification studies should be taken with a major grain of salt until it’s known how it was done.

  25. Theo,

    You know that ‘mainstream climate scientists ” are ABOVE actually doing empirical stuff.

    Models…models , models..

    juggle, jiggle, fudge.

  26. Any respectable biologist would passionately fight to support the cause against deforestation.

    Or, conversely, they could build a ginormous home in the Vancouver area, eat lots of pretzels, and persist in self-serving behaviour, under the guise of saving the world from anthropogenic climate induced destruction. Just saying.

  27. Kinda ironic that the green movement has decided to attack one of the main substances that makes the Earth greener, ie. CO2.

  28. And that the Green poster child of wind turbines is probably among the most environmentally destructive and avian life minimising devices ever created by man.

  29. Hah! James Lovelock found over 40 years ago that that phytoplankton released DMS from the ocean to form cloud overhead to cool the surface. They are still doing it and I bet much more effectively than land plants.

  30. Steven Mosher says:
    April 28, 2013 at 3:37 pm
    …………….
    like good skeptics they didnt swallow the koolaid as some here perhaps did. they went out to prove it.

    How about also offering this great piece of advice to the climate scientists. Let them ‘prove’ positive feedback via observations out there in the field over say Europe. By the way I thought you can’t ‘prove’ anything in science.

    phlogiston:
    Mosher is not a scientist and neither am I. ;)

  31. I read from the above press release:

    That means that especially in places like Finland, Siberia, and Canada this feedback loop may reduce warming substantially.

    But I was told we are were doomed. I notice that the boreal forests have in recent years been hammered by more snow. Could it be that climate scientists have over the years been observing natural climate changes as opposed to anthropogenic induced thermageddon? Just askin’.

    April 2007
    Climate-induced boreal forest change: Predictions versus current observations
    Abstract
    ……We suggest that there is substantial evidence throughout the circumboreal region to conclude that the biosphere within the boreal terrestrial environment has already responded to the transient effects of climate change. Additionally, temperature increases and warming-induced change are progressing faster than had been predicted in some regions,…..

  32. A further point to consider with forests is that, in areas where snow lies in winter, the season that the snow remains is longer within the forest than on open ground. As a result, the reflective albedo effect of snow lasts longer in forested areas than in deforested ones.

    It appears intuitively obvious, therefore, that sensible, strategic replanting of forests is one contributory factor toward abating warming scenarios.

    To me, this is far more sensible than shutting down all power stations immediately.

  33. An interesting question is whether all plants emit the same amount of aerosols per hectare and are they of equal effectiveness. So, for example, when in response to warmist hysteria, the rain forests are replaced with sugar cane or oil seed palms for the production of bio fuels does this increase or decrease the warming/cooling response. i.e. are the warmists in fact really warmists contributing directly to warming via their insane bio-fuel projects.

  34. Jimbo Says.
    “Mosher is not a scientist ”

    Which does explain the basic lack of scientific understanding inherent in the large majority of his posts.

  35. This is just another desperate attempt on the Climate Fictionists’ part to stay in business. Aeorosols, whether manmade or natural give them an “out”, and wiggle room (or so they think). The warming is still there, you see, it’s just being hidden by all these other factors, so we just need to add these other factors back into the models to make them better. Riiiiight.

  36. Jimbo quotes… “Additionally, [b]temperature increases and warming-induced change are progressing faster than had been predicted in some regions[/b]”

    Clearly talking about the ocean under 700m there!

  37. Rob:

    Please cite your evidence for your astonishing assertion concerning “the ocean under 700m” that ” temperature increases and warming-induced change are progressing faster than had been predicted”.

    Richard

  38. Did someone mention koolaid? This “study” is a good example. They take their standard, sour C02-centric climate formula, add a good helping of sweetness in the form of actual science to make it go down easier, and presto! Whoever mentioned koolaid above didn’t seem to understand how it’s made, so I’m happy to help him out.

  39. The contribution of aerosols to climate forcings is guesswork. Known is, however, that trees are the largest source of methane to the atmosphere [Pangala et al., New Phytol. 197: 524-531, 2013] . Rising atmospheric methane concentration correlates with global warming even more than carbon dioxide [Reay et al. in “Methane and climate change”, Earthscan, 2010]. Hence, scientific consensus on arborgenic global warming (AGW) calls for immediate large-scale lumbering. Save nature: cut down the trees !

  40. Over land dust is king. Over the oceans salt and organic compounds are king. Of greater importance, wind appears to be the driver of changes in these major sources of aerosols and the climate community laments they can’t get their models to reproduce the wind (or clouds, or El Nino events, or La Nina events, or no ninoa events or…etc, etc, etc). Do you suppose this is why they try to compensate by producing their own wind? Gas from plant flatulence has to be a new low in investigating the minutia of the h-air on a gnat’s ass.

  41. This is completely OT and absolutely not meant for posting but where else is there to say this : I am having trouble getting on to and around in WUWT. Is it my computer or have others been having trouble?
    I hit the WUWT website and get a strip ad at the top of the page, so I hit Refresh and get another ad, Refresh again and perhaps I get in or perhaps another ad ( 6 is the record so far). Then I get the first item and nothing else. So the whole thing starts again. Eventually I get the listed articles and choose one to read and hit either the title or Continue reading and get more ad/refresh, ad/refresh until I can read the article but no comments. This has started very recently, in the last 9 days, and is frustrating and time-consuming. Is this just me?

  42. You can actually see this in action. Drive along I-8 in southern California. You will notice a drop in the temperature between the east and west Canals (where they irrigate the land to farm).

  43. Has anyone mentioned that CO2 causes Global cooling because it was figured that it has a negative feed back? LMAO!!

  44. phlogiston asks (at April 28, 2013, 3:32 pm above) about how much area is required to keep a person alive. The UN’s Food and Agricultural Organization calculated in 1993 that it was as little as 0.17 acre per person. But that is under ideal conditions (no land degredation, water shortages, post-harvest waste, human errors by the farmer in planting times, crop choices, etc) and it assumes a subsistence diet.

    Dr David Pimentel of Cornell more reasonably calculated that to support one person on a diverse Western diet requires just over 1 acre of “average” land.

    Interestingly, you can support more people on a given unit of land by adding meat to their diet because the animals are able to exploit land which is unsuitable for cultivated crops. But it has to be the right kind of meat. Grazers like beef are good for land usage. Grain-fed animals like poultry work against you on the person/acre basis.

  45. Jimbo was highlighting the amazing claim of the study’s preamble that CO2 warming has proceeded at unexpectedly high rates in some regions, I joked that the “regions” they meant must have been <700m in the ocean because based on surface temp, that's crazy talk.

  46. phlogiston says: “…rent-seeking politically driven scientists like Steve Mosher”

    I thought everyone knew that Mosher is an English major with a career in marketing?

    Steven Mosher, B.A. Philosophy and English, Northwestern University (1981); Director of Operations Research/Foreign Military Sales & Marketing, Northrop Aircraft Northrop Aircraft (1985-1990); Vice President of “Engineering” [Marketing], Eidetics International (1990-1993); Director of Marketing, Kubota Graphics Company (1993-1994); Vice President of Sales & Marketing, Criterion Software (1994-1995); Vice President of Emerging Technology [Marketing], Creative Labs (1995-2006); Vice President [Marketing], Openmoko (2007-2009); Marketing Consultant, Qi Hardware Inc. (2009); Marketing Consultant (2010-Present); [Marketing] Advisor, RedZu Online Dating Service (2012-Present)

Comments are closed.