Runaway Global Warming

Discussion in 'Earth Science' started by Facial, Jul 11, 2014.

  1. billvon Valued Senior Member

    Messages:
    12,795
    Correct, and that makes sense.

    Let's try this. Let's say Joe Villain gets arrested for robbery and goes to court. You want to find out if the court found him guilty, so you get the court docket for the week. These are the cases you see:

    Allen Smith vs State of Washington. Verdict - not guilty.
    Joe Villain vs State of Washington. Verdict - guilty.
    Jane Doe vs State of Washington. Verdict - not guilty.
    Dave Jones vs State of Washington. Verdict - not guilty.

    Would you then decide "gee, only 25% of the verdicts listed were guilty! Therefore Joe Villain must not be guilty."
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. rpenner Fully Wired Staff Member

    Messages:
    4,833
    The vast majority of physics papers do not explicitly take a position on the question of if electrons carry electric charge, yet this is no reason to doubt physicists believe that is commonly the case.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. sculptor Valued Senior Member

    Messages:
    4,524
    I really have not done a complete comparison of science papers that address global warming nor climate change.

    All I'm posting here, is that, as phrased, the paper by Cook, et.al, does not support the previous claim in post #30 that
    in reference to my
    which was in response to the claim from post #25:
    Until i see really good data on the subject, I'll stick with:

    A tale told by a politician "full of sound and fury and signifying--------------nothing"
     
    Last edited: Jul 15, 2014
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. billvon Valued Senior Member

    Messages:
    12,795
    Fair enough. Fortunately, several people have done just that and made their conclusions available.
    A good summary of denialism.
     
  8. Truck Captain Stumpy Registered Senior Member

    Messages:
    709
    @billvon
    this is not the specific paper to which I was referring, but here is a good paper to argue the point about consensus: http://www.pnas.org/content/early/2010/06/04/1003187107.full.pdf
    Published 2010, it holds the key to one reference of 97% consensus.

    I will continue to search for the other article/publication .. my memory remembers certain details, but cannot remember where it was
     
  9. Truck Captain Stumpy Registered Senior Member

    Messages:
    709
    Here is another article that is quite cogent and speaks about a completely different set of numbers regarding the published papers
    The article, published on AAAS on Jan 10, 2014 seems to have stirred a few comments too

    http://blogs.scientificamerican.com...s-on-global-warming-9136-agree-one-disagrees/
     
  10. billvon Valued Senior Member

    Messages:
    12,795
  11. iceaura Valued Senior Member

    Messages:
    24,424
    Were you typing at the time?

    I have read that for some people washing their hands is much like a religion, also believing in Sunday. Best not to have crazy religions.

    They're still good ideas, though - washing your hands, taking a day off work for gratitude and reflection, being careful with greenhouse gasses.

    It's not hard to find, if you look.
     
  12. Facial Valued Senior Member

    Messages:
    2,217
    I'm at my university library and I'm looking at the Russell paper now (Figure 1 and Table 1). At 256X (eight times doubling) CO2, the atmosphere equilibrates at a mean surface temperature of close to 140 deg. Fahrenheit! Wow!

    This is pretty close to my initial expectations from an extrapolation (tabulation) of the IPCC equilibrium climate sensitivities (AR4, 2007, Ch. 8 and TS chapter), where I did doublings all the way to the maximum limit of oxygen concentration (20.5 vol%), assuming all of it is from photosynthesis with a corresponding carbon 'conjugate' stored under the sea or under the ground. I arrived at a figure of 154 degrees Fahrenheit, since I assumed that the climate sensitivity would plateau at the upper estimate of the models listed.

    The result also agrees with Hansen's assessment (see OP for link to essay) that there would likely be a planet that is not only ice-free but also human-free.
     
  13. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152
    That's wrong. (See below.)

    The question of runaway warming is much more complicated, so let me just address the CO[sub]2[/sub] vs water vapor issue. This is a fallacy exploited by the Right in their relentless propaganda. The argument that the spectrum for water is broader is correct but you've left out a key point: water vapor concentrations are, on average, equalized to saturation. That is, concentrations can not rise above a threshold without producing precipitation. CO[sub]2[/sub] however is a trace gas and its concentrations can increase without any such limits (chemically speaking; obviously bad things would happen to the biosphere).

    BTW it's an old issue, one that was rather hotly debated in 1900. But that's how long folks have had a chance to learn that CO[sub]2[/sub] is crucial. (At the time some scientists thought it would be good thing to melt global ice, particularly since climate science was thriving in and around the Arctic Zone, in countries like Sweden, where there is an understandable affinity for solar heat.)
     
  14. billvon Valued Senior Member

    Messages:
    12,795
    Right. The issue is they can also be far _below_ those concentrations. For example, the greenhouse effect is much lower over arid areas because there is less water vapor in the atmosphere. An additional issue is that condensation (clouds) causes cooling during the day but warming at night.

    So it's not as simple as "water vapor can't go over saturation." It is perhaps the most complex question in any climate model.
     
  15. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152

    In the first place we can set aside the issue about modeling here since the historical data shows a slight increase in humidity globally over the past four decades or so. My point is simply that, on average, it will rain or snow wherever the air becomes saturated. Therefore there are severe limits to the amount of water vapor that will remain suspended in the air, whereas there are no such limits (chemically) to the concentrations of CO[sub]2[/sub]. The antagonists are arguing that the potential harm of CO[sub]2[/sub] can be ignored since water vapor is broad spectrum. In so doing they are ignoring something much more fundamental than models. They're missing the point about this more fundamental constraint on water vapor which does not apply to CO[sub]2[/sub].
     
  16. billvon Valued Senior Member

    Messages:
    12,795
    Well, clouds will form first. Then if water content is sufficient _then_ it will come down as rain. This is significant because clouds are very strong climactic drivers in both directions.

    Agreed with everything you said above. However, you have to be careful saying that "the idea that water vapor is a stronger and more important greenhouse gas is a denier fallacy" because it's actually a critical point. As you mention, that point does not overshadow the fact that CO2 is also an important greenhouse gas, and the increase in its concentration is driving much of the current warming.
     
  17. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152
    My intent is to debunk a denialist argument hijacked from a 1900 debate that went on between Arrhenius and Knut Angstrom, son of the better scientist.

    You're probably already aware of this, but for the casual reader here are two really crappy denialist arguments typical of the sludge that gets dredged up whenever the water vapor argument is mentioned.

    Arrhenius made one of the first predictions of global warming from anthropogenic CO[sub]2[/sub] in 1896. He was unaware of the major forcing functions (e.g. volcanic aerosols), so this first cut at modeling was pretty crude. But it was an improvement on Tyndall's ca. 1850 conclusion that the ice ages end due to warming from elevated CO[sub]2[/sub]. (Denialists need to be reminded of these dates since they tend to superimpose Al Gore on top of what is a long record of scientific inquiry. As we know, Gore took a class from one of the esteemed experts at NOAA, and had good reason to see the need to educate the public on science they lack, since, as we know, Americans are notoriously ignorant of first principles of science. The really stupid claim is that Gore is anything more than a messenger, whereas his facts are pretty damn good for a lay person. The denialists should be so accurate

    Please Register or Log in to view the hidden image!

    .)

    In a nutshell: around 1900 Knut Angstrom attacked Arrhenius from the stance that water vapor trumps CO[sub]2[/sub] and thus the issue is moot. This is the idea the denialists have hijacked. They want to say that climate science is a fraud because (they believe) it's following the crude (which they allege is hopelessly flawed) estimates of Arrhenius, in ignorance of what Angstrom argued in his published rebuttal.

    Basically it's a pretty shitty case of quote mining. Arrhenius was the better scientist, despite the fact that Knut Angstrom rose in influence on his father's coat tails. And most of the issues of that original debate are rendered moot by newer evidence.

    Since we are dealing with people who never sat in a lab and measured concentrations, much less have any idea what a spectrum is, it seems to me that the simplest way to debunk the myth, in terms they should understand, is to show that CO[sub]2[/sub] has no limits on its concentration (ideally, ignoring the biosphere) whereas the air on average can only hold so much water vapor before it will precipitate out. You can count clouds in that and it still doesn't matter since the average global cloud cover remains fairly constant. (And has a theoretical limit at the point the whole world is under a perpetual overcast sky.)

    As it turned out, the climate scientists of ca. 1900-1950 were of the opinion that the biosphere would keep the CO[sub]2[/sub] levels constant, and that water vapor could vary widely. They had this backwards, but then they had only scraps of evidence to work from.

    I wasn't trying to run end-around the details of climate modeling you mentioned, but rather, to nip the denialists' nonsense in the bud. It's a fairly common argument, at least from the sites and posts I've read thus far. And they can get pretty stupid about it, generally just reinforcing their denial all the more, concluding, of course, that climate science is a lie.

    Please Register or Log in to view the hidden image!



    Again, to clarify: while the spectrum of water vapor is wider than CO[sub]2[/sub], and it may appear that water vapor trumps CO[sub]2[/sub] for this reason alone, the argument fails to recognize that water vapor concentrations are relatively stable (although slowly rising, which speaks more to the overall syndrome of rising temps) whereas CO[sub]2[/sub] is not subject to the natural limitations of water vapor concentration (on average, globally) and therefore the forcing by CO[sub]2[/sub] is monotonically increasing over time. And I guess a corollary to this is that no one is talking about limiting anthropogenic water vapor (which is silly for obvious reasons that the surface water trumps human output), whereas the warnings about limiting CO[sub]2[/sub] persist for the reasons I just mentioned. The water vapor issue doesn't trump it. If anything, we have to worry that CO[sub]2[/sub] harm is amplified by water vapor, as the average humidity is slowly increasing with the human-forced temperature rise.

    As a sidebar I should add that the next 30 trace GHGs combined are about as harmful as CO[sub]2[/sub] by itself (based on recent levels of output of each).

    You're a smart guy--I could never be at cross purposes with you unless I really was on the wrong track. So keep the feedback coming. It's always good to read the posts of somebody who really is on top of his game.

    Please Register or Log in to view the hidden image!

     
  18. billvon Valued Senior Member

    Messages:
    12,795
    Again I think this is a bad argument because it is trivial to refute. Concentrations of CO2 are currently around 400ppm worldwide, and they are fairly stable with only a very minor seasonal and hemispherical variation. Water vapor concentrations vary widely from close to zero to about 40,000ppm worldwide, and the saturation point varies widely as well with temperature.
    So if you go in with "water vapor concentrations are stable but CO2 concentrations are not" then the denier wins that argument. Water vapor has a far wider range and is a far stronger greenhouse gas than CO2.
    But again no one predicts CO2 concentrations will get to 40,000ppm. And thus water vapor is both more variable and stronger than CO2. There's a maximum limit (about 4%) but CO2 will not come anywhere close to that so it's not an argument in favor of CO2 warming.
    THAT is the argument I would make. Water vapor waxes and wanes, and the amounts (and forcings) go up and down with time - but CO2 forcing is increasing relentlessly, and that forcing is only going up with time.
     
  19. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152
    The point is that they are monotonically increasing, and all of the evidence says it's (in part) from anthropogenic causes.

    Now average that over all of the globe and you'll be on the same page as me. I'm exclusively addressing global averages for both GHGs.

    Now recast that as averaged over all of the atmosphere. While it's true that average humidity is slightly rising, it can not conceivablely rise faster than some maximum slope, which is small, whereas CO[sub]2[/sub] concentrations (due to human emissions) can rise without bound.

    If you accept that nature limits the positive slope on the graph of humidity over time, then maybe you'll be on the same page with me. I think that's the difference between what you're saying and what I'm saying.

    Remember that the denialists have no clue what you're talking about. And I'm debunking the nonsense of the sort that appeared in those two junk sites I linked to. So again, if we limit this to global averages only (average over the volume, not necessarily time), then I think you'll probably agree with me.

    Again: on average, global humidity is limited by the average effect of water vapor saturation leading to precipitation. On average, there is x amount of water vapor coming off of all surface water and ice. On average, that vapor distributes across the regions which are not arid, such that it can reach saturation. Upon reaching saturation, it will precipitate. Thus, on average, there is a natural hard limit to water vapor concentration.

    Acknowledging, of course, that since global warming is in progress, the arid regions are slowly shrinking and the average saturation point of the humid regions is slightly increasing over time. For this reason, we want to emphasize that anthropogenic carbon is raising the otherwise natural thresholds of water vapor concentration, which increases the anthropogenic harm rather than trumping it as the denialists would have their sheeple believe.

    I'm guessing you are are in agreement with me, but feel free to set me straight if I've misunderstood you.

    Please Register or Log in to view the hidden image!

     
  20. Truck Captain Stumpy Registered Senior Member

    Messages:
    709
    There is an especially cogent video in an article on phys.org that should be watched about Global warming... the link is here: http://phys.org/news/2014-07-problem-false-science.html

    The video is a comedian, but it really DOES address some pertinent issues in HOW the issues is addressed in the media.
    And of course Bill Nye had to be there to help out!

    Although the video is funny, it really is far more lucid and factual than many Anti-global warming arguments I have seen to date.

    I hope yall enjoy it as much as I did.
     
  21. Facial Valued Senior Member

    Messages:
    2,217
    Wanted to point something out in case a few people are not sure about my understanding of the subject: CO2 is the main driver of climate today, and will likely remain so for a long time. The range of humidity is pegged to the temperature, which is (presently) pegged essentially to CO2 concentration. Humans emit about 130X more CO2 than other natural sources combined, and this has been long documented by careful measurements by the USGS and Charles Keeling.

    I thought that H2O becomes more 'independent' for stronger phases of warming because of the Maxwell-Boltzmann distribution*: imagine the upper end of the tail by geometric arguments can look like a very fat right triangle. It is the 'tail' in the distribution of velocities that is responsible for particles breaking free from a liquid into the vapor phase (the reason why a puddle of water evaporates at room temperature). In this case, changing the length of the base of that triangle changes the area approximately linearly for small changes in the base length, as the height hardly changes for a fat triangle. For modest temperature increases, this linearity is preserved, which may account for the linear increase in humidity concomitant with temperature rise. However in the extreme case we also know that at a little above the boiling temperature, all the molecules are in gas form and the lower tail does indeed have a portion of molecules whose velocities are not 'supposed to be a gas.'

    We can expect both from the distribution shape of molecular velocities and the phase change beyond a certain temperature that the rate of evaporation increases with larger temperature increases. Realistic physics from the OP shows that water vapor does increase climate sensitivity for increased warming but does not take on 'a life of its own,' i.e. unbounded acceleration. One of the factors that I can already see hindering the process is the pressure increase from a more massive atmosphere favoring the liquid phase.

    *Actually the real distribution shape for a liquid is probably somewhere in between a Maxwell-Boltzmann and a Bose-Einstein distribution. But the key feature is that the variance of molecular velocities increases as temperature increases.
     
  22. billvon Valued Senior Member

    Messages:
    12,795
    But the denier still wins because water is a far stronger greenhouse gas than CO2 - and it's varying and hard to predict.

    AND by temperature. Thus as the air gets warmer it will be able to hold more water, which will increase the greenhouse effect in the lower atmosphere. So the denier argument goes "so we had a few warm years, and now the atmosphere can hold more water, so of course temperatures are going up!"

    So that's why I wouldn't use that.

    Which is slowly increasing.

    Hmm. Everything that I have seen has indicated that arid regions are shrinking while humidity is growing, since higher temperatures hasten the transfer of water from ground to air. That's certainly true out here.

    To reiterate, I agree with your underlying ideas. I think it is a mistake to minimize the effects of water (both condensed and vapor) on climate change. The topic gives climate researchers fits and there's no solid answers on what effect it will have. I think it's a better approach to say "we're not sure what will happen to the forcing caused by water as the climate gets hotter, since it's a much stronger forcing than CO2, but we are sure that the steady contribution from CO2 is driving average temperatures up."
     
  23. Facial Valued Senior Member

    Messages:
    2,217
    Are you referring to Roger Revelle? He founded my institution, UC San Diego, in 1964 while still working at the Scripps Institution of Oceanography, but I haven't read about him being a part of NOAA.

    Actually SIO started a new professorship, the Roger Revelle professorship. The first holder of the chair is Shang-Ping Xie, who recently put out a paper on Pacific equatorial cooling explaining the recent 'hiatus' in global warming. What I haven't been able to reconcile, though, is the relative strengths of his argument versus that of Foster and Rahmstorf in 2011 when they got very good linear fit subtracting out the variations caused by El Nino, volcanic aerosols, and solar irradiance.
     

Share This Page