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.
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.
Originally posted by seanD
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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.
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