Another unknown climate feedback – plankton blooms create brighter clouds

Marine plankton brighten clouds over Southern Ocean

From the NASA/GODDARD SPACE FLIGHT CENTER

New research using NASA satellite data and ocean biology models suggests tiny organisms in vast stretches of the Southern Ocean play a significant role in generating brighter clouds overhead. Brighter clouds reflect more sunlight back into space affecting the amount of solar energy that reaches Earth’s surface, which in turn has implications for global climate. The results were published July 17 in the journal Science Advances.

Satellites use chlorophyll's green color to detect biological activity in the oceans. The lighter-green swirls are a massive December 2010 plankton bloom following ocean currents off Patagonia, at the southern tip of South America. Credits: NASA's Earth Observatory

Satellites use chlorophyll’s green color to detect biological activity in the oceans. The lighter-green swirls are a massive December 2010 plankton bloom following ocean currents off Patagonia, at the southern tip of South America. Credits: NASA’s Earth Observatory

The study shows that plankton, the tiny drifting organisms in the sea, produce airborne gases and organic matter to seed cloud droplets, which lead to brighter clouds that reflect more sunlight.

“The clouds over the Southern Ocean reflect significantly more sunlight in the summertime than they would without these huge plankton blooms,” said co-lead author Daniel McCoy, a University of Washington doctoral student in atmospheric sciences. “In the summer, we get about double the concentration of cloud droplets as we would if it were a biologically dead ocean.”

Although remote, the oceans in the study area between 35 and 55 degrees south is an important region for Earth’s climate. Results of the study show that averaged over a year, the increased brightness reflects about 4 watts of solar energy per square meter.

McCoy and co-author Daniel Grosvenor, now at the University of Leeds, began this research in 2014 looking at NASA satellite data for clouds over the parts of the Southern Ocean that are not covered in sea ice and have year-round satellite data. The space agency launched the first Moderate Resolution Imaging Spectroradiometer (MODIS), instrument onboard the Terra satellite in 1999 to measure the cloud droplet size for all Earth’s skies. A second MODIS instrument was launched onboard the Aqua satellite in 2002.

Clouds reflect sunlight based on both the amount of liquid suspended in the cloud and the size of the drops, which range from tiny mist spanning less than a hundredth of an inch (0.1 millimeters) to large drops about half an inch (10 millimeters) across. Each droplet begins by growing on an aerosol particle, and the same amount of liquid spread across more droplets will reflect more sunlight.

Using the NASA satellite data, the team showed in 2014 that Southern Ocean clouds are composed of smaller droplets in the summertime. But that doesn’t make sense, since the stormy seas calm down in summer and generate less sea spray to create airborne salts.

The new study looked more closely at what else might be making the clouds more reflective. Co-lead author Susannah Burrows, a scientist at the Pacific Northwest National Lab in Richland, Washington, used an ocean biology model to see whether biological matter could be responsible.

Marine life can affect clouds in two ways. The first is by emitting a gas, such as dimethyl sulfide released by Sulfitobacter bacteria and phytoplankton such as coccolithophores, which creates the distinctive sulfurous smell of the sea and also produces particles to seed marine cloud droplets.

The second way is directly through organic matter that collects at the water’s surface, forming a bubbly scum that can get whipped up and lofted into the air as tiny particles of dead plant and animal material.

By matching the cloud droplet concentration with ocean biology models, the team found correlations with the sulfate aerosols, which in that region come mainly from phytoplankton, and with the amount of organic matter in the sea spray.

“The dimethyl sulfide produced by the phytoplankton gets transported up into higher levels of the atmosphere and then gets chemically transformed and produces aerosols further downwind, and that tends to happen more in the northern part of the domain we studied,” Burrows said. “In the southern part of the domain there is more effect from the organics, because that’s where the big phytoplankton blooms happen.”

Taken together, these two mechanisms roughly double the droplet concentration in summer months.

The Southern Ocean is a unique environment for studying clouds. Unlike in other places, the effects of marine life there are not swamped out by aerosols from forests or pollution. The authors say it is likely that similar processes could occur in the Northern Hemisphere, but they would be harder to measure and may have a smaller effect since aerosol particles from other sources are so plentiful.

###

The research was funded by NASA, the U.S. Department of Energy and a graduate fellowship from the Air Force Office of Scientific Research.

Read the paper at Science Advances: advances.sciencemag.org/content/1/6/e1500157

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102 thoughts on “Another unknown climate feedback – plankton blooms create brighter clouds

  1. ok which way was the wind blowing in that pic ?“In the summer, we get about double the concentration of cloud droplets as we would if it were a biologically dead ocean.” and how would they know this ??
    also nothing to do with the increased heat as heat does not create evaporation

    • “heat does not create evaporation” Huh? Evaporation cannot happen without heat to cause the change of state.

      • Evaporation cannot happen without heat to cause the change of state.
        Yep. Heat of vaporization (enthalpy) = 540 calories per gram

      • So it is self regulating. More plankton leads to more and brighter clouds, which shut off sunlight and reduces the plankton blooms.

    • yeah, flea.
      Correlation.
      Causation.
      We may have the former without the latter.
      More data is needed, I suggest, but interesting comments!
      Auto – intrigued, none the less, as it may be the ‘The Science is NOT settled’

  2. Since these are phytoplankton, the negative feedback need not only be through temperature. The direct fertilizer effect of atmospheric CO2 could also increase the concentration of phytoplankton (and their effects on clouds). That could in principle lead to negative “feedback” on temperature from higher CO2. This is not the case for feedback controls that depend on temperature. At most, such controls could completely offset any direct effect of CO2 on temperature.

    • Sounds like you need a grant to study the effect of Arthropodic Climate Change. Interesting consideration though, no joke.

    • Is there also a precipitation response? Do they produce clouds and rain downwind that produce cool waters with nutrients, like co2 disolved in precipitation on the way down from the atmosphere, up-current?

    • Iron is typically the limiting nutrient in marine water but maybe with more CO2 in the water the plankton will become more efficient in their use of iron.

      • It’s possible, but I’m dubious. Lots of CO2 in the ocean already.
        Iron Fertilization should get double points for fighting global warming. It sequesters CO2 deep in the ocean, and brightens clouds. As a side bonus, it greatly enhances fish stocks. And it’s dirt cheap.
        Because it is so beneficial, it is illegal.
        Maybe environmental activists hell bent on breaking the law should dump rust in the ocean instead of chaining themselves to trees.

      • I’m not so sure iron is a limitting factor as inhibiting factor. I doubt all bio processes are limited by iron, just the most active/fastest ones we’re most observant of.

    • Good post Peter. There is no doubt that additional CO2 increases phytoplankton blooms. Yet one more reason for reduced climate sensitivity.

    • Now plankton blooms may increase the absorptions of solar energy in shallower waters, rather than it propagating deeper as it does in clear waters.
      That in itself will tend to raise the temperature of those shallower waters, and that would lead to more evaporation which leads to more clouds.
      Don’t need to postulate plankton farting to make rain drops.

      • Well Mark, just what is a “brighter” cloud.
        Clouds are formed from water droplets or ice crystals, and the H2O in that water evaporated from the liquid surface, as a single molecule of H2O. It did not cart off with it, and complex organic molecules that was a product of a zooplankton chomping on some phytoplankton.
        Cloud “brightness”, more accurately called “luminance”, is nothing more than the density of the water droplets, and their number.
        A water droplet, that condensed on a soot particle is no more luminous, or less luminous, than a droplet, that condensed on an amoeba, or on a cosmic ray charged particle offspring. Both scatter light through refraction, and the amount scattered is simply a function of the amount of sunlight intercepted by the droplet; in other words, its size. And more droplets will scatter more light and so make the cloud more luminous.
        If the paper’s authors assert that there is a luminous difference between water droplets, depending on the nature of the substrate on which it grew, then they need to provide experimental measurement proof of those differences.
        g

  3. Sounds plausible.
    #flea- clouds need nucleation particles for the vapour to form on to form droplets which come from the plankton presumably.

    • dimethyl sulfide puts it firmly under recorded phenomena such as the Tambora eruption and the year without a summer.

    • All feedbacks are positive? (except when they’re not – and then we don’t talk about them)

    • Maybe this? ” In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible.” …

      • Original Mike, I will make a more precise prediction: At no time in the year 2016 will the average daily temperature of earth exceed 20°C, unless we get hit by a giant meteor or some other out-of-system event. The point being that coupled non-linear chaotic systems often (always?) have limits.
        Consider the graphic. Near as we can figure, over the past 800,000 years earth’s temperature anomaly has varied in a chaotic manner but never more than about +/- 0.5°C. The satellite temperature record shows a maximum year-on-year change of 0.85°C over it’s 37 year life. Therefore, I can predict with some confidence that the 2015-2016 anomaly will not be greater than about 1°C. I can be certain but I’m so confident of this prediction that I’ll wager $1.
        We can’t predict even linear, non-coupled systems in the real world because there are no linear, non-coupled systems in the real world.
        When we dance, the earth wobbles.
        http://earthobservatory.nasa.gov/Features/GlobalWarming/images/epica_temperature.png

      • David A. Good point. There are none! Make that +/- about 6°C. Wrong numbers but the point is still valid. It’s bounded chaos.

  4. UV solar radiation varies to large extent with solar cycles. The UV effect on the plankton concentration needs to be considered.

    • Yes………and include too, the effects on the airbourne organic matter resulting from the plankton bloom, subjected to increased Cosmic Rays, also varying with solar cycles over the short and longer term periods.

      • Thank you. I read it twice thinking I’d missed some mention of energized particles and their impact on the natural aerosols in cloud formation. They are apparently myopic in their focus of research.

      • The interesting aspect for me, of variable solar UV output, is its possible connection with atmospheric structure (and in particular the correlation with the Azores High and cold NW European winters and NE N. American cold winters).
        Quote: Thus the spectral composition of solar radiation is crucial in determining atmospheric structure, as well as surface temperature, and it follows that the response of the atmosphere to variations in solar irradiance depends on the spectrum2. Daily measurements of the solar spectrum between 0.2 µm and 2.4 µm, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite3 since April 2004, have revealed4 that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding.
        from – http://www.nature.com/nature/journal/v467/n7316/full/nature09426.html and http://solarphysics.livingreviews.org/Articles/lrsp-2007-2/download/lrsp-2007-2Color.pdf
        see also – http://arxiv.org/pdf/1306.2770.pdf (S. K. Solanki, N.A. Krivova, J.D. Haigh)

    • Wonder what the direct reflection off of the plankton mass is. Sure is visible in that satellite picture.

    • Yep. And we also need to consider that traits develop that don’t necessarily benefit a species. They can persist and propogate so long as they generally aren’t too harmful.

    • Good question, Vukcevic,
      “bacterioplankton … find it difficult to consume long-chained dissolved organic carbon. Solar UV breaks down these long molecules, and the bacteria can consume the fragments faster. This increases the transparency of the water and the penetration of solar UV to greater depths. One feedback loop is that solar UV damages the bacteria, decreasing their numbers”
      http://www.photobiology.info/Hader.html

      • Lewis, Good point. See my further comments at 1:15 PM. Seems like solar cycles could affect phytoplankton because UV increases 0.5% while visible light increases on 0.1% meaning that the critters have to go to lower light levels to find low enough UV levels. But I’m sure the real relationship is far, far more complex!

  5. I kept looking for a mention of increased plankton blooms during the period studied. But no joy. The picture is for December 2010, but the smaller droplets of Southern Ocean clouds was in 2014. In other words, it looks like models all the way down. How about some validation?!
    Oh, it turns out that “the modeled sulfate concentration, the modeled OMF, and the satellite data do not represent the same years.” Never mind.

  6. Upwelling, the secret solution is in upwelling. Upwell nutrients from below to feed the plankton at the surface (where the sunlight is) and – presto! – you will have before you a plankton bloom.
    And a plankton bloom will cool the earth and a cooled earth will not produce boiling seas – boiling seas of acid.
    The earth will be saved!

    • There was a proposal (or an idea, or whatever) many years ago to tap into the temperature differential between warm surface waters and cold waters from the abyss to generate electricity. The proposal suggested extending a large pipe to the abyss to pump up the cold water from way below – and along with it (as a byproduct) would be pumped up much-needed nutrients (much-needed nutrients for the mostly nutrient starved plankton that lived at the surface).

      • That sounds like a recipe for tapping into hell and bringing the goblins to the surface where they will reproduce and take over the Earth. It can happen.

  7. For ‘settled science’ there do seem to be a lot of unknown unknowns appearing. And if they are not modelled then the results are not likely to be accurate – as indeed they aren’t.

  8. These folks should work in Svensmark’s cosmic ray hypothesis too, as he claims that’s part of the link from DMS to H2SO4 to sulfate aerosols to low maritime clouds in relatively clean air.

    • So just suppose we take their theory as gospel truth. Plankton blooms cause more brighter clouds.
      So what ?? That is all just a part of the natural variability of the environment. And remember that climate is measured over 30 years; otherwise it is just weather.
      So have they found these more and brighter clouds persisting for 30 years, or maybe what about just the last 18 years and six months.
      Their paper may be interesting to people who may see a plankton bloom as being a positive for ocean life productivity.
      Can’t see that it is otherwise of any consequence. Just more taxpayer dollars going up in smoke supporting otherwise unemployable “science” graduates.
      But then Anthony’s measure is stuff that is interesting. So it’s interesting. Plankton blooms affect ocean life; sometimes good, sometimes bad; it all depends.
      But the sky is not falling; this process has presumably been going on for hundreds of millions of years.

  9. organisms modify their environment to aid in their survival. those that make the biggest change have the greatest advantage. those that don’t go extinct. Plankton has been controlling the earth’s climate for the benefit of plankton, for a very long time.
    No doubt Obama and the IPCC will speak up in Paris this December and bring the naughty phytoplankton into line. Shame and blame them for all the climate change they have caused over the past 1000 billion years.
    White House officials remain cautious however, that Plankton might yet turn the tables and demand their fair share of the 100 billion annual World Carbon Fund. Officials were quick to dismiss the role of Plankton in turning deadly CO2 into pure Oxygen. However, at $30 dollars a ton for CO2, the nations of the world are projected to run out of paper and ink to print money long before they settled what they owe Plankton.

  10. Just some physical chemistry info;
    Dimethyl sulfide: Boiling point 35 to 41 ºC Melting point -98 ºC.
    Dimethyl sulfoxide: Boiling point 189 ºC. Melting point 19 ºC
    Dimethyl sulfone: Boiling point 238 ºC. Melting point 109 ºC,
    So it is perfectly possible that dimethyl sulfide oxidizes to sulfoxide or sulfone and these form aerosol particles in the upper atmosphere.
    What I don’t know is why they use models.

    By matching the cloud droplet concentration with ocean biology models…

    Or what exactly those ocean biology models are

    • You and me both Pamela. I think I’ll have a beer, suggest you do likewise.
      This morning, my local MacDonalds ran out of CO2, so they weren’t selling any soft drinks. Well I don’t drink that stuff anyway.
      I talked to a lady at the Safeway store; standing by their 57 varieties of milk, and I asked her why they didn’t have any just milk, milk . She didn’t know. So I added that all of their organic milk had carbon in it, and the SCOTUS said that’s poisonous.
      She responded; “Wow, that’s good to know !”

  11. Another effect is on the transparency of the ocean, less transparency means a smaller volume of water being heated directly by sunlight, hence higher surface temperatures, lower deep ocean heat.

    • Good point. Phytoplankton cool the upper ocean by shading the depths and converting energy into living matter, some of which leads to carbon sequestration.
      Is the additional reflectivity and the conversion to living matter instead of heat locating some of the ‘missing heat’?

      • Indeed, it should be obvious, but not alas quantified, that SW radiation penetrating deeper into the oceans will have longer residence time, thus more potential energy flux in total energy over a given period of time due to any increase or decrease.

  12. A MODEL, and they found a CORRELATION.
    I am so excited.
    Any models around to explain why such a polar and hydrophillic molecule should get in the atmosphere and stay there long enough to have an effect on anything. Seems to me that DMS was recently “discovered” to be produced by plankton, and now everybody is finding that DMS is soooo important in their own little area. Nothing more than another fad with a molecule “de jour”.

    • Is DMS DiMethyl Stilbestrol ?? izzat some female hormone ? I once used a Stilbene Crystal as a scintillation detector for neutrons. I think it is better than Anthracene if my memory serves me.

    • *sigh*
      I have to explain everything to the youngsters, these days.
      These are aerobic algae creating DMS, in an oxygen rich environment, presumably from environmental sulfate.
      (please ignore the fact that reduced sulfur compounds are made by chemosynthetic bacteria under anaerobic conditions)
      A side reaction caused by Ocean Acidification, catalyzed by sulfur free radicals which are an intermediate of DMS production, is the reduction of H+ to H2 gas. It is the evolution of the hydrogen gas in these macro-aerosols which loft them high into the stratosphere, where they sulfatise back to sulfate, under the influence of UV radiation, causing the clouds to brighten, and lighten up. When you model this system correctly, this is just what you would expect. Which proves the model and the theory correct.
      Remember,

      I would like to know how you do that.

      you asked.

    • Raindrops don’t get that big. Also, cloud droplets smaller than .1mm are common. The Wikipedia article for cloud mentions .002mm radius (.004mm diameter) as a normal size of cloud droplets.

      • the size of the drops, which range from tiny mist spanning less than a hundredth of an inch (0.1 millimeters) to large drops about half an inch (10 millimeters) across.

      • Cloud condensation nuclei start with a molecule and work up. At about 20 nanometers (0.02 microns) they start to have significant influence and grow rapidly, often in a supersaturated mass of air that was pregnant with possibilities, just short of something to start condensing on.
        On the opposite end you can prevent the evaporation of water to a temperature significantly above 100C by putting the water in a very smooth ceramic container that has been washed with sulfuric acid to remove tiny pricks and hairs. The record before boiling is about 200 C. See http://www.ucl.ac.uk/sts/staff/chang/boiling/index.htm#5 for some cool experiments. Use protection.
        Getting droplets to form has its own interesting deviations from the expected.
        Water droplets smaller than 0.0001 mm are invisible to us because they don’t interfere with visible light. Visible clouds therefore have to be made up of particles larger than this.
        A great many particles in clouds are frozen. As the particles of water are frozen, they release heat (which then appears as IR) which is transmitted off the white surface upwards more than downwards (because it is white below). If thermals drive a lot of wet clouds high enough that they freeze, the energy is not evenly radiated back to Earth. A slight warming will produce massive additional cooling, Willis and alla that.

    • Well for your information , 10 mm across, is NOT half an inch. Try 12.7 mm in diameter.
      So we already know about what their error bands are.

    • Yes, and it was part of undergraduate biology training in the1980s.
      Common knowledge to any marine biologist today.

      • Indeed I remember learning about dimethyl sulphide from plankton seeding clouds in my early 80’s oceanography degree course.
        Of course, more CO2 means more phytoplankton primary production and eventually, via dimethyl sulphide etc, more cloud albedo. Yet another biologically related negative feedback opposing climate warming by CO2.

  13. None of the quotes say anything about “feedback”. It may or may not be a positive or negative feedback depending on how changing conditions affect the competing populations of the differently emitting plankton.
    There is really nothing new here other than using satellite data to estimate the effect. Robert Charlson pointed out all of this over 25 years ago.
    The Original Mike M will note that I too have altered my signature to make the difference less subtle.

  14. Results of the study show that averaged over a year, the increased brightness reflects about 4 watts of solar energy per square meter
    That’s about 2x the anthropogenic forcing as published by the IPCC…
    I wonder what the derivative is – how much does the reflection change per additional degC? That would determine the feedback loop effects.
    Peter

  15. From the article:

    To represent these processes in a changing climate will require models capable of representing the dynamic response of ocean biology to the warming and acidification of the oceans and to the retreat of sea ice and predicting the subsequent effects on natural aerosol sources.

    Um, what retreating sea ice? Especially in the Antarctic, the sea ice is advancing…

  16. So… where’s the source code and the data? Another publishing fail…
    I note they make use of a nice algorithm for robust interpolation and smoothing. Willis take note, it looks pretty good to my signal processing eyes. I wish I’d have this for some ECG work about 17 years ago…
    http://www.biomecardio.com/pageshtm/publi/csda10.pdf
    And actual source code that was also in the paper!. Now that’s how you do it.
    http://www.biomecardio.com/matlab/smoothn.html#7
    Peter

  17. Thank you for this paper. This explains nicely the negative feedback mechanism that caps the temperature rise after coming out of an ice age.

      • Dawtgtomis If there were any substantial positive feedbacks in the climate system you would not be around to ask that question and I wouldn’t be answering.

      • Matt, “If there were any substantial positive feedbacks in the climate system you would not be around to ask that question and I wouldn’t be answering.”
        This statement is not precisely true.
        Greenhouse gases cause substantial positive feedbacks, making the plant much warmer than it would otherwise be, but the effect is capped so there is no run-away warming.

      • Thomas, I think he’s referring to the historical cycle of cooling followed by warming rebounds.allowing human populations to recover from the reductions caused by ice ages. We indeed would not have survived had there not been some positive forcings of the climate (heliospheric, orbital and oceanic in my perspective). I guess my comment was a flippant wish that we wouldn’t have to endure a repeat of the dalton minimum or worse.

      • Oops, sorry Matt, misread your comment. I see now that you were referring to the Venusian effect of runaway warming. Although, who’s to say what evolution might have done to develop a species that is at home in a dense, hot atmosphere. makes one imagine cockroaches or maybe chelonian reptiles…

      • There seems to be a misunderstanding as to what a’positive feedback’ is. It doesn’t mean a feedback that increases temperature.
        It is “the amplification of an effect by its own influence on the process which gives rise to it”.
        A positive feedback refers, just as easily, to a decreasing temperature (and anything else.)
        I don’t know whether this interpretation is universal.

  18. Phytoplankton move in response to light. They move towards light (towards the surface) to increase photosynthesis and away from light (to greater depth) to avoid excessive destructive UV radiation. When phytoplankton are near the surface, the surface layer is warmer, because the plankton absorb sunlight and shade the water below. When the surface is warmer, air near the surface is also warmer. When phytoplankton move to depth, e.g. to avoid damaging UV radiation, the ocean surface is cooler and the air above the surface is also cooler. Solar UV varies by about 1.5% from minima to maxima whereas total solar radiation varies only about 0.1%. This could cause a dilemma for phytoplankton during solar maxima because photosynthetic light increase only slightly but UV increases. If phytoplankton are less productive, and further from the surface, during solar maxima, that could cause the surface to be cooler, but they would also produce fewer cloud nuclei, which would tend to make the surface warmer. It’s a fascinatingly complex process.

      • …more total energy flux into the oceans for two reasons, less absorption in the near surface layers, and a decrease in cloud cover. We appear to be a long way from quantifying these things.

  19. Others have mentioned it, but this post shows how the science is certainly not settled. Humanity is a long, long way from having a “settled” climate science. The one thing that we can demonstrate is that CO2 is not the “control knob”.

  20. “The study shows that plankton, the tiny drifting organisms in the sea, produce airborne gases and organic matter to seed cloud droplets, which lead to brighter clouds that reflect more sunlight.”
    Yea, I got a kick out of the brighter cloud thing. I never knew clouds came in different levels of brightness.

  21. Why are they continuing to do research on anything climate? This can’t be true; the science was settled before this paper, wasn’t it? There is no room at the inn of knowledge; go find a stable somewhere.

  22. Would undersea volcanic activity improve the Fe nutrition available to plankton, helping facilitate a bloom?

  23. There are often some glimpse of realism in such papers.
    At least we now have a confirmation of what we could expect a priori:
    “Aerosol processes remain a poorly understood influence on clouds (4). Processes regulating the concentration of naturally occurring aerosols, in particular, remain a major source of uncertainty, limiting our ability to quantify the magnitude of the human impact on climate from aerosols (5, 6).”
    “Because of the complexity of chemical and physical interactions affecting sea spray production and processing in the atmosphere, experimental and observational studies have been unable to unambiguously determine whether marine organic aerosol derived from phytoplankton is associated with an increase or with a decrease in CCN and Nd in marine clouds.”

  24. In the paper it is claimed:
    “Aerosols influence clouds by acting as the cloud condensation nuclei (CCN) on which cloud droplets form, and the resulting concentration Nd of cloud droplets influences the amount of sunlight reflected by clouds (3). ”
    Reference (3) is:
    S. Twomey, Pollution and planetary albedo. Atmos. Environ. 8, 1251–1256 (1974).
    For your convenience, here is a link to the paper:
    http://www.clidyn.ethz.ch/ese101/Papers/twomey74a.pdf
    I propose that you skim through this paper – which is referred to as basis for the above statement.
    In my opinion, it does not even closely resemble a scientific approach to the issue.
    Science or fiction? – I would say fiction!
    If you disagree – please reply and let me know.

  25. This is how IPCC summarized on aerosol-climate feedback:
    “Aerosol-climate feedbacks occur mainly through changes in the source strength of natural aerosols or changes in the sink efficiency of natural and anthropogenic aerosols; a limited number of modelling studies have assessed the magnitude of this feedback to be small with a low confidence. There is medium confidence for a weak feedback (of uncertain sign) involving dimethylsulphide, cloud condensation nuclei and cloud albedo due to a weak sensitivity of cloud condensation nuclei population to changes in dimethylsulphide emissions. {7.3.5}”
    (Ref. Working group I contribution; on the scientific basis; to the fifth assessment report by IPCC; TS.3.7 Climate Feedbacks)
    To put the language straight: On this area there is no established theory which has been exposed to and stood up to rigorous testing.
    Science or fiction? – I call it fiction!

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