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Global warming causality

  1. Jan 22, 2007 #1
    After reading several papers and seeing gore's movie on GW I'm still searching for solid scientific causal evidence (versus correlations or circumstancial) that anthropogenic greenhouse gases are the cause of global warming in the post-industrial age. I accept we are in a warm epoch, atmospheric CO2 is higher than average, humans have made CO2 levels higher, and natural CO2 levels correlate historically with temperatures. This may be enough for some, but it still does not prove human causality. I'm not rejecting the thesis of human causality for global warming, just would like to read a scientific argument that doesn't rely on correlation, circumstances, or simulations. Is that's all there is?
  2. jcsd
  3. Jan 23, 2007 #2
    Good thinking, the same reasoning has to be applied to the anti-human GW camp [this should read anti--human--caused] (just read some anti human GW papers). Its all statistics - induction -......... Now what do we do? Each camp claims their data, their conclusion, their inferences are correct.

    Now, both camps acknowledge that there is warming in certain regions and even in global average. Point has to be given to the non-linear thinking camp where we note that even local temp change can have global effects. There is much thoughts going this way as it should.

    But yes, you need to choose which one to belief just like with any science.
    Last edited: Jan 23, 2007
  4. Jan 23, 2007 #3
    As a statistical problem GW suffers because it's impossible to conduct a controlled experiment, so perhaps all we can do is rely on correlations. There is nothing wrong with that, it just makes it impossible to quantify statistical inferential error.

    I note much of the alleged inference comes from complex models and simulations, which has its own problems -- assumptions, modeling accuracies, etc. And if GW is like other fuzzy sciences I'm pretty sure a model that gives the "wrong" answer is thrown out or tweaked until it gives the right answer.

    I said perhaps this is the best we can do. I've wondered, what would lead me to accept human caused GW (or not accept it) on a more solid basis? How about an energy budget calculation from first principles? The atmosphere is a storage system. So much heat comes in from the sun and earth, so much goes out from reflectance and earth/ocean conduction. Starting with a balanced temperature, how much delta T is expected from, say, a 100ppm CO2 increase? Not saying this is a simple calculation but, if from first principles, the answer is either a negligible increase, or a lot, that may say whether human caused GW is reasonable. With a gazillion papers out there, surely someone has attempted such a calculation?
  5. Jan 23, 2007 #4
    Go to goole scholar and type your question there. "co2 increase temperature calculation", and others variations of that. There are tons of papers on that.
  6. Jan 23, 2007 #5

    Ivan Seeking

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  7. Jan 23, 2007 #6
    Thanks, sneez. So it appears that my question was first posed by Arrhenius in 1896 and remains a topic of current research, see "Arrhenius’ 1896 Model of the Greenhouse Effect in Context," with an abstract here

    Arrhenius' 1896 prediction from first principles was that a doubling of atmospheric CO2 would warm the Earth by 5-6 °C. From what I understand current models predict a 1.5-4.5 °C.

    I'll read more about that, thanks.
  8. Jan 23, 2007 #7
    Just for the record, this was the fate :eek: of the mega post I prepared here.

    The question posed is the main discussion item here.

    But there is no significant correlation between CO2 and temperature. Not in the ice coes, not in the hockeystick, not even now. It takes quite an effort to substantiate that but it's all in that discussion. Highly recommended for comparing the science.
    Last edited: Jan 23, 2007
  9. Jan 23, 2007 #8

    Ivan Seeking

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    It seems that over 600 leading scientists and a world class panel says that you're wrong.
  10. Jan 23, 2007 #9
    Last edited: Jan 23, 2007
  11. Jan 23, 2007 #10

    Ivan Seeking

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    Well, I could ask the guy who is asking for money down by the freeway, but I choose to put my faith in the experts; and not unqualified internet debates among amateurs.
    Last edited: Jan 23, 2007
  12. Jan 23, 2007 #11

    Ivan Seeking

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    By the way, those who are not experts are supposed to appeal to authority. That's why we have experts.
  13. Jan 23, 2007 #12
  14. Jan 23, 2007 #13
    Well, there is no need for this layman heated discussions. When CFCs were the issue a protocol controling CFC was proposed. That was so much fought against and scientists payed by corporations were to find evidence that CFCs do not cause ozone hole and ozone depletition. Lets guess, evidence was found that CFCs do not cause ozone depletition and x other reasons were found. Now we know that CFC do cause ozone hole and all the mechanism, it was through heterogenos chemistry that was not known or considered before in the atm that this was confirmed. The protocol is in effect and there is ozone recovery.

    Just a note from history how things usually happen.

    The truth is that both sides are worthy investigating and no need yet to call for scientific dishonesty (in general for any of the supporters of either theory). This should be learning experience.

    Ander i find your papers good reference points to other point of view.
  15. Jan 23, 2007 #14
    <When experts keep telling that they are right because the models say so then they have abandoned the scientific method and hence rely on autority.>

    Andre, I agree, and thanks for those links, that is the type of first principles paper I've been trying to find. As I commented earlier, sneez pointed me to other first principle papers that argue for anthropogenic warming. I can accept that different studies may conclude different results, based on their assumptions, data accuracy, etc. But I can't accept arguments based on blind reliance on experts, black box computer models, corporations, or politicians. Furthermore, I'm always suspicious when I see thousands of "experts" reproducing similar results, it smacks to me of stacking the deck by funding certain answers. If the science is good, a few studies are enough, then we should move to the next problem.
  16. Jan 23, 2007 #15
    "If the science is good, a few studies are enough, then we should move to the next problem."

    I understand your emotion, but its way too simplified. Science is historical and philosophical as much as political and at the last little experimental. Do not let intro books into science fool you. I also had my romantic views of science shattered after couple years of doing it.

    If you belief that white light is composed of colors you are victim of what you call blind reliance. If you belief there is inverse square law of gravity the same, and i could continue for some time. (But they would close the thread, so lets proudly claim we belief all those things, and abhore "experts").

    just making a point.....that its not that easy and let experts be experts. Susan solomon who is on the review comitee is such a good scientist that none of us can approach her in life time. (figurativelly). She has level of science which all of us should be learning. Dont throw everyting into one bag. She contributed to geosciences as much and profoundly as many known main stream physicists.
  17. Jan 23, 2007 #16
    With reference to the original post, there is no conclusive evidence that the observed global warming is caused by industrial anthropogenic gas releases. I am of the opinion that we have contributed to global warming, it is undeniable that we have raised the level of CO2 in the atmosphere, and it is undeniable that CO2 is a greenhouse gas. This does not mean that we have caused global warming, it is possible that the earth was heating up anyway! Perhaps we're just making it worse than it would otherwise have been?

    Besides, it is not the CO2 itself which we should be most worried about. We must be concerned with the possible effects of the melting of the ice sheets, and the onset of positive feedback mechanisms that could trigger a large mass of greenhouse gases to be released.
  18. Jan 24, 2007 #17
    The question is what effect has radiative gas anyway. Without greenhouse gasses, the atmosphere cannot exchange radiative energy. The key word is "exchange". Sure there is greenhouse effect, about 0.95K per doubling CO2 in radiative balance without any feedbacks, but there is also increased radiation out, as seen by the increased cooling of the stratosphere. Moreover (need to find the papers later) but satelite measurements reveal that IR with CO2 signature (freq spectrum) is mainly emitted from a cold source (around -55C) which suggest stratosphere, while water vapor signature has a much warmer source, suggesting troposphere. This would make the feedback idea a bit complicated.

    Furthermore positive feedback, which is required to boost up the doubling temperature to 1.5 - 4.5 degrees or what is it, is never been proven yet disproven by several seperate mechanisms.

    Here is one:

    Here is another

    the last glacial transition in the EPICA Dome C ice cores shows a clear lagging of the CO2 signal not influencing the leading isotope signal. This used to be the main straw of the empirical global warming positive feedback evidence until the high resoltion of todays proxies are telling us a completely different story. So this graph moves from positive evidence of global warming to refuting the mechanism of global warming due to the increase of greenhouse gas. But who wants to know that.

    The urge to save humanity is almost always only a false-face for the urge to rule it, H.L. Mencken
  19. Jan 24, 2007 #18
    Andre, indeed CO2 has cooling effect middle atmos. but also a warming effect.

    The rate of CO2 cooling is also more involved it depends on 1) kinetic temp, 2) CO2 abundance, 3) rate coeff for collisional deactivation of CO2(0,1,0), 4)
    O(3P) number density.

    The CO2 cooling rate is not the same in the strato and meso as it is in lower thermosphere. Different bands of CO2 have different effect.

    There are many uncertainties which may introduce 50% error. Those are O(3P) concentration and rate coefitients co2->o.There is significant from solar near IR heating of CO2 through vib energy being thermalized by N2.

    CO2 cooles atm at night generally BUT net heating can still result at cool high levels due to absorbtion of lower level radiation.

    Clear and complete discussion of mechanism of cooling and heating by all molecules relevant is in the book : NON-LTE radiative transfer in the amtosphere by lopez-puertas.

    The point is the more optically thick troposphere (in ir )the bigger the GH effect. CO2 is major contributor to that.

    To be more complicated, there are ozone feedbacks to variations of CO2 and with that related dynamical phenomena which may reinforce CO2 proceses.
    O3 is very important for radiative balance of atmos.

    It would be foolish to argue about these things just from radiative perspective or just chemical or dynamical. Thats why its not so easy. It would be nice to say "all else remaining the same, doubling of CO2 has this and that effect". Well, its not that simple. The rates and effects we observe are due to all the interaction of all players. Thats why using those and leaving all else the same will not tell us much or it will be incomplete picture.

    Yes, if we have laboratory atmosphere, we can, but in real one there is still more science needed to go both ways.
    Last edited: Jan 24, 2007
  20. Jan 24, 2007 #19
    Andre, sneez, I appreciate the complexity of the GW science much better from the papers and comments you've provided. The Karner paper is interesting in its findings contrary to positive feedback, though the data set is pretty sparse. And the CO2 temperature (proxy) graph puts into question the causality that is so widely claimed.

    One further question, how well do these studies and models account for the rate of CO2 increase rather than its absolute level? Are the predictions of x degrees change for y percent change in CO2, with or without feedback, based on steady state end states, or do they account for the shock of rapid CO2 increase we've seen in the last couple of hundred years?

    In the language of dynamic nonlinear systems, could such a shock cause a rapid bifurcation of global climate into a different state without much warning? Analogous to, say, laminar fluid flow quckly becoming turbulent.

    I'm aware of the theoretical scenario in which Greenland melts causing ocean currents to change and throwing the earth into an ice age. I'm not referring to that kind of macro causality. What I mean is, could the shock of rapid CO2 increase cause some fundamental change in the dynamics, say a reversal from antipersistence to persistence between atmospheric transfer at different levels, and climatic dynamics are suddenly reversed? Are climate models sufficiently granular to replicate such potential effects?
  21. Jan 24, 2007 #20
    As far as i know (i may be wrong), the rate of CO2 is assumed constant or change lineary or only responds to SSE. This is huge problem in the models, for the rate might be more important than the actual concentration.

    I did not study on my own these models but from what i know in general about them the answer is, no.

    There is going on much research and finally realizing that phtochemistry and chemistry itself is non linear. Its all dynamic processes from radiative transfer to chemistry, but to solve those equations is not possible. So we develop methods of solving them numericaly (and or SSE-steady state approach used most of the time). There is plethora methods but all have pros and cons and ALL OF THEM cannot be generalized to long term. Most of them do not conserve (converge) in long time, and many other problems.

    There is much uncertanties with vegetation forcing, ocean-atm feedback etc.

    It has been shown that even local changes in vegetation (too small to resolve in models) can have large scale irreversible impact in temperature (like turning amazon forest into desert) (this is not GW). Hysteresis or irreversibility -> changes that perist in the new post disturbance state even when the original level of forcing is restored. This may be consequence of multiple stable equilibrium in the coupled systems-> which atm certainly is.

    Then there is issues of how to distribute probabilities in the models of events happening...

    For your sake read this of understanding: http://stephenschneider.stanford.edu/Publications/PDF_Papers/M00037347.pdf

    That about how much i know about this, which is very little...
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