Great thread, Gm - and some interesting work. I know several people working in cosmic ray showers but none in this field.
Cosmic Rays and Climate
- Thread starter Gothmog
- Start date
Gothmog
Dread Enforcer
- Joined
- Sep 19, 2002
- Messages
- 3,352
Ayatollah So wrote:
The one hypothesis I've heard that makes any sense is to inject sulfur into the stratosphere. There it forms reflective aerosols (i.e. cooling) that only have a couple few year lifetime. This is the primary way that volcanos affect climate as well. This was put forward by Paul Crutzen (nobel prize winner), and another excellent scientist whose name now escapes me though I worked in a department where he was the chair... (edit: that's Ralph J. Cicerone).
One problem here is that there will always be winners and losers in any climate change situation. I don't think were ready for that type of action yet, but we should study the possibilities because it could become necessary.
@ainwood
Svensmark has been the author of a number of controversial papers, as I outline in the OP. His most recent work on empirical correlations is not very strong (again see the OP), and it only claims a change in low cloud amount (as seen from space in the infrared) of 2-3% for a 15-25% change in GCR flux. This is not a very strong effect, nor does it consider what the effects of those clouds would be on climate.
The publication I assume you're thinking of is his new experimental work done in a big chamber, and which leads into the upcoming CERN work.
As I've noted, I am somewhat of a fan of this work. I've done this sort of experimental work myself in the past (though with much less funding). There are problems with direct interpretation of the results though, that discussion would be quite technical but we can go there if you want.
The misrepresentation was that those experiments in some way showed that current climate models are wrong. It isn't all Svensmark's fault, if you read the paper he specifically says that is not the case (I have the paper at work, I'll try to get the quote and post it here). The thing is his institute is trying to get its funding re-upped, and he is trying to get the CERN experiment going (very expensive). So the marketing guys in his government institute were very aggressive in their press release. Then there have been a number of articles (newspaper, magazine) that go way beyond credible interpretation of his results.
I have more on this at work, including I think some comments from one of his coauthors (a postdoc) about the press release and subsequent coverage.
Bottom line though is that if you read the article as published in the scientific literature you would never think it lead to all the outrageous statements published in the popular press.
@TLC Yeah, thus 'economically viable', as prices rise alternative energy sources become more and more viable as well further reducing demand for oil. Also, we could very well come upon some more efficient way of producing energy in the next few decades - especially as the price of energy rises because that reduces the marginal cost of R&D. Finally, I consider much of the US's involvement in the middle east a subsidy of oil prices as it now stands.
@Goa I thought we might see Mon Mauer (?), or theimmortal1, show up because they both have brought this up in global warming threads recently and both seem to be technically competent. But I guess not, my hope is that when anyone brings up this topic in the context of global warming people will link to this thread, especially the OP.
This sort of geoengineering is being studied. The problem with trying to change tropospheric clouds is that they can warm or cool the atmosphere depending on their location, altitude, and droplet size distribution.
The one hypothesis I've heard that makes any sense is to inject sulfur into the stratosphere. There it forms reflective aerosols (i.e. cooling) that only have a couple few year lifetime. This is the primary way that volcanos affect climate as well. This was put forward by Paul Crutzen (nobel prize winner), and another excellent scientist whose name now escapes me though I worked in a department where he was the chair... (edit: that's Ralph J. Cicerone).
One problem here is that there will always be winners and losers in any climate change situation. I don't think were ready for that type of action yet, but we should study the possibilities because it could become necessary.
@ainwood
Svensmark has been the author of a number of controversial papers, as I outline in the OP. His most recent work on empirical correlations is not very strong (again see the OP), and it only claims a change in low cloud amount (as seen from space in the infrared) of 2-3% for a 15-25% change in GCR flux. This is not a very strong effect, nor does it consider what the effects of those clouds would be on climate.
The publication I assume you're thinking of is his new experimental work done in a big chamber, and which leads into the upcoming CERN work.
As I've noted, I am somewhat of a fan of this work. I've done this sort of experimental work myself in the past (though with much less funding). There are problems with direct interpretation of the results though, that discussion would be quite technical but we can go there if you want.
The misrepresentation was that those experiments in some way showed that current climate models are wrong. It isn't all Svensmark's fault, if you read the paper he specifically says that is not the case (I have the paper at work, I'll try to get the quote and post it here). The thing is his institute is trying to get its funding re-upped, and he is trying to get the CERN experiment going (very expensive). So the marketing guys in his government institute were very aggressive in their press release. Then there have been a number of articles (newspaper, magazine) that go way beyond credible interpretation of his results.
I have more on this at work, including I think some comments from one of his coauthors (a postdoc) about the press release and subsequent coverage.
Bottom line though is that if you read the article as published in the scientific literature you would never think it lead to all the outrageous statements published in the popular press.
@TLC Yeah, thus 'economically viable', as prices rise alternative energy sources become more and more viable as well further reducing demand for oil. Also, we could very well come upon some more efficient way of producing energy in the next few decades - especially as the price of energy rises because that reduces the marginal cost of R&D. Finally, I consider much of the US's involvement in the middle east a subsidy of oil prices as it now stands.
@Goa I thought we might see Mon Mauer (?), or theimmortal1, show up because they both have brought this up in global warming threads recently and both seem to be technically competent. But I guess not, my hope is that when anyone brings up this topic in the context of global warming people will link to this thread, especially the OP.
Gothmog
Dread Enforcer
- Joined
- Sep 19, 2002
- Messages
- 3,352
I just was looking at the Svensmark paper and he actually doesn't address climate models at all in it, I was thinking of another revew article I read recently. But here's a quote from the discussion section:
Now, here's a quote from one of the coauthors of the Svensmark 2007 paper I mention in the OP. This comes from an online discussion with other scientists.
Now, here's a quote from one of the coauthors of the Svensmark 2007 paper I mention in the OP. This comes from an online discussion with other scientists.
Hmm, sounds reasonable. No?
I remember an article in Scientific American authored by Keppler and Rockwell (I think) where they discuss the natural productions of methane. They emphasised over and over how their findings did NOT undermine current scientific thinking on climate change.
Gothmog
Dread Enforcer
- Joined
- Sep 19, 2002
- Messages
- 3,352
A simple energy balance model for mars...
Energy in = Energy out
Energy in is all from the sun.
At 1 AU (the earth sun distance) the solar constant is about 1366 W/m2 (see the OP).
So at the mars-sun distance of 1.5 AU the solar constant is (by the inverse square law): 1366*(1/1.5)^2 = 607 W/m2
Mars has an albedo of 0.16, i.e. it reflects away 16% of all energy incident upon it, so we are left with: 607*(1-0.16) = 510 W/m2
Energy out is due to blackbody radiation. This is given by: sigma*T^4
Here sigma is the stefan boltzmann constant (sigma = 5.67*10^-8 W/m2/K4), and T is the radiating temperature.
The only other factor is geometry (i.e. the per meter squared issue in the 'energy in' and 'energy out' terms derived above).
Any planet recieves energy from the sun as a disk of area piR2, and radiates it as a sphere of area 4*pi*R2.
To summarize: Energy in = Energy out
piR^2 * 510 = 4piR^2 * sigma * T^4
Now we solve for T...
T = (510/4/sigma)^(1/4) = 218 K
What is the empirical temperature of Mars?
According to 'http://www.nineplanets.org/mars.html' it is 218 K
Note that this is an average over day and night, and over it's eliptical orbit, etc. etc. I actually wasn't expecting such an exact answer, that's just a coincidence.
Energy in = Energy out
Energy in is all from the sun.
At 1 AU (the earth sun distance) the solar constant is about 1366 W/m2 (see the OP).
So at the mars-sun distance of 1.5 AU the solar constant is (by the inverse square law): 1366*(1/1.5)^2 = 607 W/m2
Mars has an albedo of 0.16, i.e. it reflects away 16% of all energy incident upon it, so we are left with: 607*(1-0.16) = 510 W/m2
Energy out is due to blackbody radiation. This is given by: sigma*T^4
Here sigma is the stefan boltzmann constant (sigma = 5.67*10^-8 W/m2/K4), and T is the radiating temperature.
The only other factor is geometry (i.e. the per meter squared issue in the 'energy in' and 'energy out' terms derived above).
Any planet recieves energy from the sun as a disk of area piR2, and radiates it as a sphere of area 4*pi*R2.
To summarize: Energy in = Energy out
piR^2 * 510 = 4piR^2 * sigma * T^4
Now we solve for T...
T = (510/4/sigma)^(1/4) = 218 K
What is the empirical temperature of Mars?
According to 'http://www.nineplanets.org/mars.html' it is 218 K
Note that this is an average over day and night, and over it's eliptical orbit, etc. etc. I actually wasn't expecting such an exact answer, that's just a coincidence.
Similar threads
