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Thread: Answer to SeanD on the Cloud Cover hypothesis

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    tWebber Leonhard's Avatar
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    Answer to SeanD on the Cloud Cover hypothesis

    I open this thread here because I didn't want to derail Cow Poke's criticisms of the New Green Deal (which I don't know enough about to criticize or defend). This thread will primarily be scientific in nature. Moderators will confirm that global warming threads, whether scientific or political in nature have taken place in Civics, so I ask that the thread get to stay.

    Mountain Man, you may post here, but I ask you to stick to the subject of this article, and not wander off into other subjects. That goes for others as well.

    Quote Originally Posted by seanD View Post
    We know most politics behind man-made climate change is self-serving bullcrap, but we'll see at least from climate change scientific circles how serious they are about the facts based on how they respond (or don't) to this recent study.
    The Svensmark effect is perhaps the most interesting alternative primary driving force of the Earth's global climate other than CO2.

    It was actually proposed all the way back in 1997, and there's been active research into it. There's also been plenty of media attention around it, at least on the level of ordinary popular science.

    The idea is that cloud cover correlates with the background radiation. The more radiation the stronger, the more clouds, the stronger the cooling. The mechanism is that the highly energetic particles leave a trail of water clusters. Tiny balls made of dozens and dozens of water molecules. Basically nano droplets. These then grow as they collide with other water molecules. This, so the hypothesis goes, causes more clouds to occur. And clouds reflect sunlight, thereby decreasing the amount of heat the Earth gets exposed to. Svensmark documented several places where an increase in the background radiation, was correlated with a decrease in global temperature. While correlation wasn't perfect, it was still very interesting and enough reason to launch a scientific investigation.

    The article that SeanD links to is another such correlation between a period where the cosmological background radiation changed (in this case going up) correlated with a similar change in the Earth's temperature. There have been plenty of those. Though for all them none of them can really explain the rapid increase in temperature since the fifties. I know enough about Svensmark to know that he considers CO2 a greenhouse gas.

    I know a bit about this hypothesis because I did a bit of laboratory work assisting an old Professor Emeritus at Aarhus University - Institute of Physics and Astronomy, who was trying to replicate a particular hard to replicate aspect of it. We used a particle accelerator that was configured almost exactly like one of the old Calutron accelerators from the Manhatten project. Using it we aimed a beam of ionized particles accelerated up to around 500kev, and collided them with water measuring the results on a mass spectrometer.

    And we got water ion clusters of various sizes. This is one step that was necessary. In doing that we were simply replicating results from the CERN CLOUD experiment which used a much more powerful accelerator, and got even better results, but it made for an interesting exercise and it gave the old emeritus a chance to teach a new generation of students to work with old equipment. I have fond memories of him.

    The CLOUD experiment is where the meat is at. They've been researching actively this topic for the past decade.

    http://cdsweb.cern.ch/record/1257940...PSC-SR-061.pdf
    https://authors.library.caltech.edu/...re10343-s1.pdf
    http://www.readcube.com/articles/10.1038/nature12663
    http://adsabs.harvard.edu/abs/2016Sci...354.1119D

    The results have been that it is both very difficult to use this mechanism to generate sufficient water ion clusters, and for them to grow on their own. They considered a wide variety of mechanisms, and interactions with other aerosols and found that the effect is more pronounced when sulfuric acid is present (but later determined it wasn't by much), or when biological molecules were present.

    Overall the conclusion seems to be slowly heading towards the idea that its a very small contributor to climate change, but its not the dominant effect. And in situations where we find correlations between cosmological background radiation, and temperature, the effect will explain part of that, but there's likely to be other contributing causes as well.
    Last edited by Leonhard; 07-14-2019 at 12:10 AM.

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    See, the Thing is... Cow Poke's Avatar
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    Every problem is the result of a previous solution.

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    tWebber Teallaura's Avatar
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    Text of the Green New Deal Resolution

    Okay, so above ground nuclear testing bad. Non-issue now. Low level radiation not as bad - but how not as bad and what happens over time?

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    tWebber
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    Quote Originally Posted by Leonhard View Post
    I open this thread here because I didn't want to derail Cow Poke's criticisms of the New Green Deal (which I don't know enough about to criticize or defend). This thread will primarily be scientific in nature. Moderators will confirm that global warming threads, whether scientific or political in nature have taken place in Civics, so I ask that the thread get to stay.

    Mountain Man, you may post here, but I ask you to stick to the subject of this article, and not wander off into other subjects. That goes for others as well.



    The Svensmark effect is perhaps the most interesting alternative primary driving force of the Earth's global climate other than CO2.

    It was actually proposed all the way back in 1997, and there's been active research into it. There's also been plenty of media attention around it, at least on the level of ordinary popular science.

    The idea is that cloud cover correlates with the background radiation. The more radiation the stronger, the more clouds, the stronger the cooling. The mechanism is that the highly energetic particles leave a trail of water clusters. Tiny balls made of dozens and dozens of water molecules. Basically nano droplets. These then grow as they collide with other water molecules. This, so the hypothesis goes, causes more clouds to occur. And clouds reflect sunlight, thereby decreasing the amount of heat the Earth gets exposed to. Svensmark documented several places where an increase in the background radiation, was correlated with a decrease in global temperature. While correlation wasn't perfect, it was still very interesting and enough reason to launch a scientific investigation.

    The article that SeanD links to is another such correlation between a period where the cosmological background radiation changed (in this case going up) correlated with a similar change in the Earth's temperature. There have been plenty of those. Though for all them none of them can really explain the rapid increase in temperature since the fifties. I know enough about Svensmark to know that he considers CO2 a greenhouse gas.

    I know a bit about this hypothesis because I did a bit of laboratory work assisting an old Professor Emeritus at Aarhus University - Institute of Physics and Astronomy, who was trying to replicate a particular hard to replicate aspect of it. We used a particle accelerator that was configured almost exactly like one of the old Calutron accelerators from the Manhatten project. Using it we aimed a beam of ionized particles accelerated up to around 500kev, and collided them with water measuring the results on a mass spectrometer.

    And we got water ion clusters of various sizes. This is one step that was necessary. In doing that we were simply replicating results from the CERN CLOUD experiment which used a much more powerful accelerator, and got even better results, but it made for an interesting exercise and it gave the old emeritus a chance to teach a new generation of students to work with old equipment. I have fond memories of him.

    The CLOUD experiment is where the meat is at. They've been researching actively this topic for the past decade.

    http://cdsweb.cern.ch/record/1257940...PSC-SR-061.pdf
    https://authors.library.caltech.edu/...re10343-s1.pdf
    http://www.readcube.com/articles/10.1038/nature12663
    http://adsabs.harvard.edu/abs/2016Sci...354.1119D

    The results have been that it is both very difficult to use this mechanism to generate sufficient water ion clusters, and for them to grow on their own. They considered a wide variety of mechanisms, and interactions with other aerosols and found that the effect is more pronounced when sulfuric acid is present (but later determined it wasn't by much), or when biological molecules were present.

    Overall the conclusion seems to be slowly heading towards the idea that its a very small contributor to climate change, but its not the dominant effect. And in situations where we find correlations between cosmological background radiation, and temperature, the effect will explain part of that, but there's likely to be other contributing causes as well.
    That is a very interesting post leonhard. It would perhaps be interesting to look at the large number of potential natural contributors to both warming and cooling. This planet has gone through many significant changes in climate. Looking at what we know about and understand might be helpful in understanding what the scale and scope of the current warming is, as well as help to understand why the human component is seen as significant relative to other known factors.

    Jim
    He will reply, ‘Truly I tell you, whatever you did not do for one of the least of these, you did not do for me."

    "So in everything, do to others what you would have them do to you, for this sums up the Law and the Prophets"

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    tWebber Leonhard's Avatar
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    Quote Originally Posted by Teallaura View Post
    Text of the Green New Deal Resolution

    Okay, so above ground nuclear testing bad. Non-issue now. Low level radiation not as bad - but how not as bad and what happens over time?
    Not sure if this applies to the Svensmark hypotesis.

    The radiation from nuclear fallout wouldn't have much of an effect. Even after all the nuclear bomb tests from the US and the Soviet Union, as well as the Chernobyl and Kyshtym nuclear power disasters, the global background radiation was only at most doubled. Most of that has settled as dust on the soil now, save for the atomic fallout from the above ground nuclear tests.

    Compare that to the background radiation at a high altitude of 6 or 8 miles which is twenty times above normal background radiation. Which means a two-day tour at Pribyat at the Chernobyl Nuclear Power Plant (provided you don't enter the protected core area and stay outside the SAFE confinement), will expose you to less radiation than a transatlantic flight.

    Also the effect wouldn't be bad but welcome.

    High energy particle radiation (such as cosmic background radiation) -> Nucleation of aerosols in the upper troposhere (the nano droplets) -> Increased cloud formation (the droplets absorb water from the air and become clouds) -> More clouds which leads to a lower albedo (the clouds reflect light) -> The Earth absorbs less heat.

    That's the general idea. So if there was an increase in radiation, it would - granted that Svensmark's hypothesis is correct - lead to a decrease in global temperature. A negative temperature forcing.

    Or did you post in the wrong thread?

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    tWebber Leonhard's Avatar
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    Quote Originally Posted by oxmixmudd View Post
    That is a very interesting post leonhard. It would perhaps be interesting to look at the large number of potential natural contributors to both warming and cooling. This planet has gone through many significant changes in climate. Looking at whatcwe know about and undetstand might be helpful in understanding what the scale and scope of the current warming is, as eell as help to understand way the human component is seen as significant relative to other known factors.

    Jim
    I've always been fascinated with this hypothesis. The correlations were interesting enough to draw it out as a possible explanation, and certainly a candidate for being another significant driver of climate change. But correlations aren't enough, you also have to demonstrate a plausible physical mechanism. And that's been tough going for this hypothesis. Its hard to get high energy particle radiation to create enough aerosols, and its hard to get those aerosols to grow fast enough.

    The CLOUD experiment has had some success in showing that organic molecules emitted from trees can drastically increase the aerosol production in response to radiation. Which is good because if its just water alone we only produce less than a billionth the amount of aerosols needed. Getting the aerosols to seed clouds effectively is also hard to demonstrate, but Svensmark and others are working on the idea that some of the aerosol molecule clusters would be electrically charged, and so attract more water molecules more effective.... on the other hand they can't stay electrically charged for long, so it remains to be seen if this mechanism suffices.

    I don't think we can rule it out yet as a minor contributer to climate change. But there's a lot of work yet to be done on it, its a far more complex mechanism than the CO2+Water Vapor feedback mechanism.

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    tWebber Teallaura's Avatar
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    Quote Originally Posted by Leonhard View Post
    Not sure if this applies to the Svensmark hypotesis.

    The radiation from nuclear fallout wouldn't have much of an effect. Even after all the nuclear bomb tests from the US and the Soviet Union, as well as the Chernobyl and Kyshtym nuclear power disasters, the global background radiation was only at most doubled. Most of that has settled as dust on the soil now, save for the atomic fallout from the above ground nuclear tests.

    Compare that to the background radiation at a high altitude of 6 or 8 miles which is twenty times above normal background radiation. Which means a two-day tour at Pribyat at the Chernobyl Nuclear Power Plant (provided you don't enter the protected core area and stay outside the SAFE confinement), will expose you to less radiation than a transatlantic flight.

    Also the effect wouldn't be bad but welcome.

    High energy particle radiation (such as cosmic background radiation) -> Nucleation of aerosols in the upper troposhere (the nano droplets) -> Increased cloud formation (the droplets absorb water from the air and become clouds) -> More clouds which leads to a lower albedo (the clouds reflect light) -> The Earth absorbs less heat.

    That's the general idea. So if there was an increase in radiation, it would - granted that Svensmark's hypothesis is correct - lead to a decrease in global temperature. A negative temperature forcing.

    Or did you post in the wrong thread?
    Yeah, you never misread anything.

    So, point? What, if anything, does this tell us to advise policy? High altitude nukes probably not it (also not gonna happen) - so, what do we do with this?


    And it's hypothesis...

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    tWebber Teallaura's Avatar
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    Quote Originally Posted by Leonhard View Post
    I've always been fascinated with this hypothesis. The correlations were interesting enough to draw it out as a possible explanation, and certainly a candidate for being another significant driver of climate change. But correlations aren't enough, you also have to demonstrate a plausible physical mechanism. And that's been tough going for this hypothesis. Its hard to get high energy particle radiation to create enough aerosols, and its hard to get those aerosols to grow fast enough.

    The CLOUD experiment has had some success in showing that organic molecules emitted from trees can drastically increase the aerosol production in response to radiation. Which is good because if its just water alone we only produce less than a billionth the amount of aerosols needed. Getting the aerosols to seed clouds effectively is also hard to demonstrate, but Svensmark and others are working on the idea that some of the aerosol molecule clusters would be electrically charged, and so attract more water molecules more effective.... on the other hand they can't stay electrically charged for long, so it remains to be seen if this mechanism suffices.

    I don't think we can rule it out yet as a minor contributer to climate change. But there's a lot of work yet to be done on it, its a far more complex mechanism than the CO2+Water Vapor feedback mechanism.
    *emphasis mine


    You're just messing with me now.


    <grumble, grumble> Gonna have to reread the stupid thing...

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    tWebber Leonhard's Avatar
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    Quote Originally Posted by Teallaura View Post
    Yeah, you never misread anything.

    So, point? What, if anything, does this tell us to advise policy? High altitude nukes probably not it (also not gonna happen) - so, what do we do with this?


    And it's hypothesis...
    Honestly Teal, its not about nukes at all.

    The kind of radiation that would drive the Svensmark effect is the high energy particle radiation from space. This radiation varies slowly in intensity over time, and would be the primary contribute - granted that the hypothesis turns out to be right - for the production of cloud-seeding aerosols.

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    Quote Originally Posted by Leonhard View Post
    Honestly Teal, its not about nukes at all.

    The kind of radiation that would drive the Svensmark effect is the high energy particle radiation from space. This radiation varies slowly in intensity over time, and would be the primary contribute - granted that the hypothesis turns out to be right - for the production of cloud-seeding aerosols.
    And that translates to having no policy implications at all, doesn't it?


    If I were still a mod I'd soooo request a thread move now!

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