A Few Things Ill Considered

A layman's take on the science of Global Warming featuring a guide on How to Talk to a Climate Sceptic.

Thursday, April 06, 2006

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Historically CO2 Never Causes Temperature Change

(Part of the How to Talk to a Climate Sceptic guide)

This article has moved to ScienceBlogs

It has also been updated and this page is still here only to preserve the original comment thread. Please visit A Few Things Ill Considered there. You may also like to view Painting With Water, Coby Beck's original fine art photography.

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16 Comments:

  • At April 11, 2006 8:22 AM, Anonymous Peter K Anderson aka Hartlod(tm) said…

    There is the issue that CO2 does not present 'greenhouse behavior' and thus is unable to produce a 'greenhouse effect'.

    Your's
    Peter K Anderson aka Hartlod(tm)

     
  • At April 11, 2006 3:14 PM, Blogger coby said…

    For a striking exapmle of CO2's greenhouse effect, just look at Venus

    This link has a nice graphic illustration of why CO2 is radiatively active (ie a GHG)

     
  • At April 12, 2006 3:05 AM, Blogger Lloyd Flack said…

    The Siberian Traps are another example of flood volcanism and consequent massive CO2 emission corresponding with a mass extinction. In this case it was with the End-Permian extinction - the biggest one of all when over 90% of species became extinct. The End-Cretaceous extinction was the second biggest.

    Granted,in both of these cases there were probably other effects aggravating the harm done by CO2 induced warming. In the case of the End-Cretaceous extinction it was a giant bolide impact. In the case of the End-Permian extinction it has been suggested that warming led to massive methane releases which doubbled the warming. The warming also could have led to sea level changes and upwellings of anoxic water.

    The suggested End-Permian temperature increase was about 10 degrees centigrade. This gives an idea of just how bad a worst case scenario for global warming could concievably get. Unlikely, I know but possible.

    The current warming is as far as I know much faster than that in these two extinctions -something that should give us pause.

     
  • At April 13, 2006 6:25 PM, Blogger Lloyd Flack said…

    A couple of corrections to my previous post.

    The End-Cretaceous extinction was the third largest mass extinction. The End-Ordovician was larger.

    And at least one more mass extinction coincides with massive flood volcanism. The End-Triassic Extinction Event occurred at the same time as the eruption of the Central Atlantic Magmatic Province.

    While there were large scale extinctions associated with the Paleocene-Eocene Thermal Maximum it was not a mass extinction event in the sense that the term is usually used. I t looks like we may need complicating factors not just a temperature increase to cause a mas extinction. Unfortunately I think habitat destruction and habitat fragmentation could be just such factors.

     
  • At April 13, 2006 7:56 PM, Blogger coby said…

    Indeed the stress that other human activities have put on so many ecosystems will definately be a handicap for adaptions that might have otherwise been possible.

     
  • At November 15, 2006 12:49 PM, Anonymous David Summers said…

    For a striking exapmle of CO2's greenhouse effect, just look at Venus

    Just a nit, but Venus is an example of what happens to planets close to the sun - it is more likely that the added heat input caused the CO2 release than that a sharp rise in CO2 caused a runaway warming trend.

    This causal relationship is at the heart of the issue. If the temperature rise causes a CO2 increase, then that means that CO2 is in some way like H2O - it has a short lifetime. Otherwise, previous temperature increases could not have been reversed. I believe the lifetime is CO2 in the atmosphere is longer than H2O, but instead of showing positive feedback, it shows negative feedback. This is because the primary method removing CO2 is rock weathering, which increases with temperature. What we may be seeing now is Humanity overwhelming the ability of weathering (and other effects) to remove CO2 - but it is inconclusive.

    I realize that CO2 is a greenhouse gas, and I don't think any serious people doubt that. I also don't think anyone doubts that humans are having an effect - the question in people's minds is: "Is the effect serious enough to try to avoid?" I think a lot of the credibility problem GW has is due to the lack of a credible answer to this question. The people backing it want to eliminate the "fun" of the other people.

    For example, a reasonable answer to global warming might be putting dust bags on all our aircraft, so that we can get more dust in the upper atmosphere. That approach could be done for the low billions of dollars (far cheaper than either curtailing oil use or allowing a global warming catastrophe), and almost provably would work if we were sure of the global warming effect. Why are approaches like this not explored? Why is the only answer to eliminate (or at least curtail) the use of oil?

    To ask this another way, pretend that tomorrow I invent the "CO2 smasher machine" that magically transforms CO2 into slime (some kind of super-algea). For $10, it solves the CO2 problem forever. Given that, would you still argue against oil usage?

    The answer is almost certainly yes - and that is where the lack of credibility happens. The discussion is all too often seen as "using science the way a drunk uses a lamppole - for support, not for illumination."

    (Sorry for drifting off-topic...)

     
  • At November 15, 2006 1:24 PM, Blogger coby said…

    Just a nit, but Venus is an example of what happens to planets close to the sun - it is more likely that the added heat input caused the CO2 release than that a sharp rise in CO2 caused a runaway warming trend.

    Venus is much hotter than mercury, and absent a greenhouse atmosphere would be only moderately warmer than earth, it is a striking example of the greenhouse effect. As for how it got that way, interesting but not relevant. You should check the ery extensive discussion of Venus on Real Climate, should be easy to find.

    This causal relationship is at the heart of the issue. If the temperature rise causes a CO2 increase, then that means that CO2 is in some way like H2O - it has a short lifetime. Otherwise, previous temperature increases could not have been reversed. I believe the lifetime is CO2 in the atmosphere is longer than H2O, but instead of showing positive feedback, it shows negative feedback. This is because the primary method removing CO2 is rock weathering, which increases with temperature. What we may be seeing now is Humanity overwhelming the ability of weathering (and other effects) to remove CO2 - but it is inconclusive.

    None of that seems to really follow, David. CO2 does have a short lifetime on geological scales, best estimates are it will take many centuries for the pulse we are putting out to come down, maybe millenia. I hae no idea why you would think a CO2 response to temperature would be a negative feedback, this certainly contradicts all paleoclimate evidence. Weathering is simply an irrelevant mitigating factor in terms of human and even societal lifetimes.

    I realize that CO2 is a greenhouse gas, and I don't think any serious people doubt that. I also don't think anyone doubts that humans are having an effect - the question in people's minds is: "Is the effect serious enough to try to avoid?" I think a lot of the credibility problem GW has is due to the lack of a credible answer to this question. The people backing it want to eliminate the "fun" of the other people.

    I think that is just a myth. There is no reason we can not develope and progress while reducing fossil fuel consumption. I sure hope so, because it is a non-renewable resource.

    For example, a reasonable answer to global warming might be putting dust bags on all our aircraft, so that we can get more dust in the upper atmosphere. That approach could be done for the low billions of dollars (far cheaper than either curtailing oil use or allowing a global warming catastrophe), and almost provably would work if we were sure of the global warming effect. Why are approaches like this not explored? Why is the only answer to eliminate (or at least curtail) the use of oil?

    People do explore ideas like this. But I think when you get in to the details it always turns out it is cheaper to conserve and transition to renewable energy.

    To ask this another way, pretend that tomorrow I invent the "CO2 smasher machine" that magically transforms CO2 into slime (some kind of super-algea). For $10, it solves the CO2 problem forever. Given that, would you still argue against oil usage?

    That would be great, but I would still argue against oil burning. It is too valuable a resource to squander the way we do, and peak oil is on us anyway. It is insanity to build everything on top of something we know for a fact will not last.

    The answer is almost certainly yes - and that is where the lack of credibility happens. The discussion is all too often seen as "using science the way a drunk uses a lamppole - for support, not for illumination."

    LOL! I like that analogy! But honestly, the serious discussions are not about living in caves again.


    [update]

    From the realclimate article I mentioned:
    "In one sense, Venus is rather similar to Earth: it has nearly the same mass as Earth, and while its orbit is somewhat closer to the Sun, that effect is more than made up for by the sunlight reflected from Venus' thick cloud cover. Because of the cloud cover, the surface temperature of Venus would be a chilly -42C if were not for the greenhouse effect of its atmosphere. In reality, the surface of Venus, at 740K (467C) is even hotter than the surface of Mercury, which is a (relatively!) pleasant 440K."
    http://www.realclimate.org/index.php/archives/2006/04/lessons-from-venus/

     
  • At November 16, 2006 12:27 PM, Anonymous David Summers said…

    I have no idea why you would think a CO2 response to temperature would be a negative feedback

    Sorry, not a negative feedback on temperature, but rather a negative feedback on CO2 levels. The point I was trying to make is that with H2O, as you get more H2O in the atmosphere it gets hotter, which puts even more H2O into the atmosphere (as you point out elsewhere, this is only stopped by the extremely transient nature of water in the atmosphere). CO2 is the opposite - as you put more CO2 into the atmosphere it gets hotter, which removes the CO2 from the atmosphere via weathering (as best I can tell). Obviously, a green house gas will cause a temperature rise until absorbed.

    My real point was that the CO2 levels in geological time scales are not really comparable to current human emissions - because on geological time scales there is a removal process. So using the geological record for proof either way is probably a bad plan.

    That would be great, but I would still argue against oil burning.

    That is the real issue - and most people see that. To put it another way, what most people say about global warming is "there is a scientific concensus", and "you can't understand it unless you are a climatologist". Both of those arguments are obviously ad hominum - trust the message because of the messenger. If that is the only way to make the argument (which may be true - this is not simple stuff), then you need to be especially careful about the flip side - the ad hominum attack. Mankind is supposed to trust you because of who you are, but one of the things you are is biased. Good, bad, or indifferent, that is how most people percieve the situation. Of course, sites like this help a lot - but even then, since the average layman can't really follow the physics, it still smells of ad hominum.

    Because of the cloud cover, the surface temperature of Venus would be a chilly -42C if were not for the greenhouse effect of its atmosphere. In reality, the surface of Venus, at 740K (467C) is even hotter than the surface of Mercury

    This is another example of my miscommunication. I did know that the atmosphere was a large contributor to the final temperature. My posit is that atmospheric effects act as an amplifier of the solar input. In other words, a 10% increase in solar activity causes a 100% increase in temperature, with about a 1000 year step response function. So a slight increase in solar activity 100 years ago can cause an exponential rise in temperature today.

    If anything, Venus is very strong evidence for this - that atmosphere is clearly doing this that are impossible at Earth's solar energy levels. You worst case numbers (at 100% CO2 absorption band saturation) is about a 10C swing, right?

    That said, my theory is certainly not proven either (though it does fit all the facts) - and if we do experience (or can forcast convincingly) global warming that is annoying to humans we should look at CO2 reduction or insolation reduction (there are many methods available, all need to be explored without bias).

    But honestly, the serious discussions are not about living in caves again.

    But they are about taking my money away from me and transfering it to your priorities (for certain values of you and me), at gun point. (I'm assuming here that you are not going to let me opt out, right?) Think about how you would feel if I forced the world's population to pay for my priorities (cheap space access for all, btw). I honestly think that this will solve 90% of the worlds problems, and is a good investment. Should I be able to gather a consensus of like minded people and force the world to pay for it?

    Again, this is why the separation of problem and solution is so important - otherwise, you are simply viewed as presenting your agenda. Global warming should not be about CO2, except to scientists. Global warming should be about how likely it is to get hot, and what we can do about it - all of the options. In other words, when global warming is suspected, and the obvious solution to scientists is to cut CO2 and the crowd reacts negatively - give them the other options, and say choose! Don't presume to choose for them - if you do that, they cannot trust you. And if they cannot trust you and cannot understand the physics, they will not avoid any possible global warming catastrophe.

     
  • At December 01, 2006 11:43 AM, Anonymous Anonymous said…

    Regarding Venus, and why it is a poor example of what could happen to Earth. Venus' mass, and consequently escape velocity, is too small to hold hydrogen. Venus may have had water 3 billion years ago, but this is gone, now. This has allowed the CO2 to persist in the atmosphere. And also, keep in mind that Venus' atmosphere is far more massive than Earth's, possibly also due to the lack of hydrogen. We are lucky here on Earth. It's just barely massive enough to keep it's hydrogen.

     
  • At February 20, 2007 6:07 PM, Anonymous Anonymous said…

    You should merge this with the other thread dealing with CO2 lagging temperature.

     
  • At March 13, 2007 4:32 AM, Anonymous Ted Westhead said…

    weathering is the pocess of breaking down rocks to its smaller constituent parts. This includes the re-release of CO2into the atmosphere and our oceans. the opposite of this would be the formation of new rock, in particular calcium cabonate which is also known as limestone or chalk. whereas this process will sequester more CO2 from our atmosphere, this is a very slow process relative to anthropogenically accelerated global warming and I don't really believe it should be used in the context of this debate.

    Keep going though, without debate, science is dead.

     
  • At August 07, 2007 7:22 AM, Blogger gail said…

    I think this is utter nonsense. The whole idea that humans with a few percent of GHG emissions are going to cause climate change is based on a theoretical science in its infancy. Think about how complex the world is? Then consider Quantum mechanics and what it says about our knowledge of the very small. Then consider our big dumb 'models' climatologists are using based on very inadequate temperature and observational data. If a model is unable to predict the weather accurately for an hour ahead, then how less accurate is it going to be over a longer period?

    It does not matter if CO2 precedes or follows higher temperatures because you cannot absolutely know one way or another. Consider how they get this data, and how they put it into the timeline! It's fraught with error.

    So here, without recourse to looking a Venus, we can see that the whole concept is flawed. A mathematical model is only as good as the data and the knowledge you have at your disposal.

     
  • At August 07, 2007 4:51 PM, Blogger coby said…

    Hi Gail,

    The theory that human CO2 might cause warming was first proposed in the 19th century, I don't think being over 100 years old qualifies as infancy. The rest of your objections are similarily unfounded, you should do some basic research into the science before trying to form such strong convictions.

    Thanks for the comment.

     
  • At December 22, 2007 12:57 AM, Blogger Barry said…

    AGW is the flat earth of today that will be laughed at by future generations. Someday, the world will look at Al Gore, and Ban Ki Moon and ask, "What were they smoking?" The AGW movement is like the butterfly effect without the ability to go back and change.

    What changes will we make to "fix" the supposed problem today that will create far greater consequences for future generations. A great example of this was the introduction of Japanese Kudzu in the southern US for erosion control. Now The South still has erosion problems but they also have a parasitic plant that kills trees and when the trees rot they fall. It takes over everything and because the natural predators don't exist in the US to control the weed, it spreads like wildfire.

    The causal affect of CO2 increase has not been conclusively established as the driving factor in temperature increase. In fact, the empirical evidence suggests the opposite. But we have some "brilliant" scientists who can look at a cat and tell us it is actually a pig. And some, foolish enough to not use the brain given them, believe, in spite of the evidence, that CO2 is the driving factor in temperature increase.

     
  • At June 05, 2008 12:33 AM, Anonymous Anonymous said…

    The causal affect of CO2 increase has not been conclusively established as the driving factor in temperature increase.

    Neither has the HIV virus 'conclusively' been determined as the cause of AIDS. Nor is there a 'conclusive' theory that 'proves' evolution. Nor is there a 'conclusive' study that exposes the link between smoking and cancer. The circumstantial evidence is so strong for these theories that they are considered to be 'true'.

    In fact, the empirical evidence suggests the opposite.

    Wrong. The empirical evidence is a test that can be performed in a class room laboratory. Shine a beam of light (infrared) through a volume of atmosphere and measure the amount of infrared coming out the other side. Increase the level of CO2 in the volume and see if less infrared is getting through.

    Done. It is an empirical fact that adding CO2 to a volume of atmosphere in the lab will absorb more heat than the same volume without the added CO2. This isn't even controversial (unless you perform the experiment with unrealistic parameters).

    How this translates to the actual atmosphere is another matter, and here is room for debate, but the empirical evidence does not counter AGW theory. It is what AGW theory is based on.

    At best you could say that some a priori evidence suggests that AGW theory is wrong.

     
  • At July 11, 2008 11:10 PM, Blogger yezi said…

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