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Clouds don't cause climate change

Discussion in 'Environmental Discussion' started by F8L, Sep 9, 2011.

  1. F8L

    F8L Protecting Habitat & AG Lands

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    I'd be interested to hear your thoughts on this study.

    Clouds don't cause climate change, study shows

    Citation: Dessler, A. E. (2011), Cloud variations and the Earth's energy budget, Geophys. Res. Lett., doi:10.1029/2011GL049236, in press

     
  2. TimBikes

    TimBikes New Member

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    Certainly more study needed on the topic, despite algore's claim that "the science is settled"...

    Cloud formation may be linked to cosmic rays : Nature News

    "It sounds like a conspiracy theory: 'cosmic rays' from deep space might be creating clouds in Earth's atmosphere and changing the climate. Yet an experiment at CERN, Europe's high-energy physics laboratory near Geneva, Switzerland, is finding tentative evidence for just that.
     
  3. chogan2

    chogan2 Senior Member

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    Dressler's paper was just one of those joy-to-read things. He takes about 3 paragraphs to demolish arguments by Spencer (recently flacked right here on Prius Chat) and a slightly older one by Lindzen and Choi. Then went on to have an intelligent analysis of the issue.

    Spencer, in particular, has repeatedly used the correlation between ENSO-driven ocean heating, and cloud cover to argue that current temperature trends are caused by changes in clouds. So, per Spencer, it's all just a big mistake, we're getting warmer due to secular changes in clouds driven by some unknown mechanism.

    What both Spencer and Lindzen failed to do -- and what Dressler did -- was a simple back-of-the-envelope order-of-magnitude analysis of the amount of heat involved. No surprise, the amount of heat imbalance caused by changes in tropic cloud cover was roughly two orders of magnitude smaller than the change in ocean surface heat content. Ergo, tropical cloud cover changes could not possibly cause ENSO heating and cooling. It has to be the other way around. (There may be some small feedback, but the operative word is small). To the extent that there is a linkage between tropical sea surface temperatures and cloud cover, it is driven by sea surface temperature changes, not by cloud cover. (Spencer also appears to have made several basic technical mistakes in his most recent analysis, and a paper pointing those out is now in press.)

    All this is unsurprising, when you think about it. ENSO heats the ocean surface by spreading already-heated water, fairly suddenly, across a wide area, displacing modestly colder surface waters. I mean, it took the better part of a century of radiation imbalance to raise mean sea surface temperatures by less than a degree centigrade. Just how unlikely is it that subtle variation in cloud cover could produce an even larger effect, on tropical ocean surface temperatures, in just one year (typical ENSO warming period)?

    So while Spencer and Lindzen focused on correlations (which are not scaled to anything), they ignored the elephant in the room, which is the amount of heat embodied in warm ENSO surface waters, and the speed with which it appears. Much, much larger than the amount of heat that the changes in cloud cover could plausibly generate.

    Anyway, it was just one of those wonderful pay-attention-to-the-basics analyses. Then went on to look at the more esosteric aspects of the analysis. Just a nice piece of analysis.


    On cosmic rays, if you want to see an even-handed discussion of the cosmic ray issue, read the most recent post on RealClimate:

    RealClimate: The CERN/CLOUD results are surprisingly interesting…

    Once again, do not miss the elephant in the room, which is, no apparent trend:

    [​IMG]

    I won't even tell you which way the trend has to go in order to generate net heating. May not be what you think, but its explained in the post.

    And in any case, it's tough to take a trendless series and argue that's the driver of temperature trends.

    So, it's interesting, so far it's all pretty much theoretical, everything I've seen suggests that the net effect is quite small in real-world terms. Gavin Schmidt concludes the post with this (GCR = galactic cosmic rays):

    "Thus the nucleation change as a result of real world GCR modulation is going to be much smaller than seen in these experiments, and much less important than the amount of pollutants."

    So, to me, that's in the same class as the ENSO-cloud correlation analysis. Correlation is great but provides no clue as to the plausibility of the underlying physical mechanism. For that, you need to pay attention to the basics. Is there a trend, is the proposed effect large enough in magnitude to provide a plausible explanation. And (of course) if this is causing the warming, explain how C02 isn't causing it (i.e., what is wrong with the basic physics calculation suggesting that C02 would cause such warming), otherwise we end up with twice the warming.
     
  4. austingreen

    austingreen Senior Member

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    Certainly those claiming settled science on ENSO and cloud formation haven't looked at how badly the model's predictions have correlated with observed results. New models only seem to get the past correct, so further study is needed. One thing the OP study does is reaffirm fairly settled science that clouds are involved more in temperature feedback, instead of the drivers of these changes. The amount of the feedback is in wide disagreement.

    It seems highly plausible that cosmic rays effect the atmosphere and cloud formation. What is unlikely is that they are causing climate change instead of climate variability. The long term patterns of cosmic rays are poorly correlated with global temperatures, to a measure that we can be confident they have not been driving the long term changes.
     
  5. TimBikes

    TimBikes New Member

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  6. cyclopathic

    cyclopathic Senior Member

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    the "small but statistically significant temperature variations (of about 0.1°C)" is just a variance which may or may not have impact on global climate. 1991 Pinatubo eruption dropped global temp 0.5°C and that did not have long term effect.

    even if CRF were to have impact on climate heating/cooling in stochastically unstable climatic points in the past, it does not mean it is a driving force of current GW trend. You cannot ignore the current anthropogenic CO2 increase.

    Edit:
    BTW the article states the significance of CRF over geological time scales (millions of years), not 10-15-25-100 years. The transition to geologically insignificant 100 year period is ridiculous at best. It is an equivalent of "today temperature 2°C cooler then yesterday, so global warming doesn't really exists". And author does not deny the impact of CO2.
    Unfortunately this is not quantified and not supported by any calculations - unsubstantiated statement at best. With respect to CO2 impact 1-1.5°C, 1.5-4.5°C, or 6°C as some suggest due to positive permafrost feedback, it is a subject to different discussion.
     
  7. chogan2

    chogan2 Senior Member

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    What cyclopathic just said. What does this have to do with the past century.

    Beyond that, it is a continuing amazement to me that people who dismiss the credibility of mainstream science because "the science isn't settled" will take the thinnest of analysis at complete face value -- as long as it says that anything other than C02 is the cause of climate change.

    Try just skimming Rahmstorf's published response to that paper, and you learn the following:

    The cosmic ray reconstruction for the past 500 million years is based on what? 50 meteorites.

    The interpretation of those meteorites' dates runs completely contrary to the conventional way in which experts in that field date meteorites.

    And it goes downhill from there.

    Read the critique, read the response, then see whom you believe. Not only is this irrelevant to the century-scale changes were seeing, it appears incorrect for the 500M year scale it is supposed to represent.

    eprints.ifm-geomar.de/11676/1/rahmstorf04.pdf
     
  8. mojo

    mojo Senior Member

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    Cosmic Rays and Climate | ScienceBits
    "Figure 1: The correlation between solar activity—as mirrored in the 14C flux, and a climate sensitivity variable, the 18O/16O isotope ratio from stalagmites in a cave in Oman, on a centennial to millennial time scale. The 14C is reconstructed from tree rings. It is a proxy of solar activity since a more active sun has a stronger solar wind which reduces the flux of cosmic rays reaching Earth from outside the solar system. A reduced cosmic ray flux, will in turn reduce the spallation of nitrogen and oxygen and with it the formation of 14C. On the other hand, 18O/16O reflects the temperature of the Indian ocean—the source of the water that formed the stalagmites. (Graph from Neff et al., 2001, Copywrite by Nature, used with permission)"
     

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  9. bisco

    bisco cookie crumbler

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    clouds don't cause climate change, climate causes climate change.
     
  10. cyclopathic

    cyclopathic Senior Member

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    Mojo,

    for the sake of argument, let me state this: I agree 100% with what the article you quote says. I don't wanna waste time arguing.

    Now let's look at following scenario: you have 3 heaters in your house. One of them you normally use, for the centuries you lived in house, and you have all statistical data confirming how it works, input, output, correlation, delay, feedback, etc, etc, etc. Then one day a dude walks in your basement, brings 40,000 BTU portable heater, hooks it up, turns it on and leaves it, and you don't know about it.

    Tell me how on earth all the data you collected on your house heater in past centuries would help you to understand why the house is getting hotter?
     
  11. TimBikes

    TimBikes New Member

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    ^^Ridiculous analogy.

    Back to Dessler, it is curious the apparent cherry picking he did in his choice of datasets for his analysis. Steve McIntyre discusses the issue here:

    More on Dessler 2010 « Climate Audit

    "CERES data, as retrieved in its original state (see here) provides all-sky and clear-sky time series. Dessler 2010 made the curious decision to combine ERA clear-sky with CERES all-sky to get a CLD forcing series. This obviously invites the question about the impact of using CERES clear-sky in combination with CERES all-sky to calculate the CLD forcing series. One would have thought that this is the sort of thing that any objective peer reviewer would ask almost immediately. Unfortunately, as we’ve seen, climate science articles are too often reviewed by pals. Nor, to my knowledge, has the question been raised in the climate community....

    ...While peer reviewers at Science were unequal to the question, the issue was raised a month ago by Troy_CA in an excellent post at Lucia’s. Having exactly replicated Dessler’s regression results and Figure 2a, I’m re-visiting this issue by repeating the regression in Dessler 2010 style but making the plausible variation of CERES clear sky in combination with CERES all sky, and with the widely used HadCRUT3 series and got surprising results.
    The supposed relationship between CLD forcing and temperature is reversed: the slope is -0.96 w/m2/K rather than 0.54 (and with somewhat higher though still low significance)."

    I'm no expert, but hmmm.
     
  12. TimBikes

    TimBikes New Member

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    A CR effect is supported on much shorter timescales here:

    http://www.astrophys-space-sci-trans.net/7/315/2011/astra-7-315-2011.pdf

    I think those who so quickly dismiss Svensmark do so at their own peril. This is not to say co2 has no effect, but it is likely not the single overwhelmingly dominant effect we are being bullied into believing.
     
  13. chogan2

    chogan2 Senior Member

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    ^^^^
    Once again, pay attention to the elephant in the room.

    There has been no trend in cosmic rays for the past 60 years. Pretty much as long as they have been measuring them.

    If you want to see a summary of what else is wrong with Svensmark's analysis, there is plenty of scholarly criticism available. Once again, read both sides and see who has the stronger argument. It's not Svensmark. E.g., putting aside the elephant in the room, others have pointed out that greater nighttime warming is contrary an hypothesis that the warming is due to changes in cloud cover. And that his analysis of Forbush events is not robust -- it falls apart if you make even tiny, reasonable changes in methods.

    So you are pushing a theory that a) could not possibly be the cause of recent warming, because there is no trend in cosmic rays, b) does not fit even the most basic qualitative aspects of the warming (greater warming at night), and c) is based in large part on some very fragile correlations observed in the data.

    If the point is to find any shred of evidence for anything other than greenhouse gasses, then this will do as well as anything else. If you're trying to make a reasoned judgment as to the most likely cause of recent warming, then not.
     
  14. dabize

    dabize New Member

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    Anyone who refers to Vice President Gore as "algore" is not here to cast light on the scientific basis of the climatic effects of greenhouse gases (CO2, CH4 etc.). That makes any post political in nature, and it should not be in this forum.

    The data set bullies all of us........I've been there, because I have done science for a living for 30 years.

    And yes, correlations that point to obvious, plausible assumptions are not proof, and those assumptions can be wrong, even when they become conventional wisdom. Climate change via the greenhouse effect (like evolution and gravitation) is not this kind of CW. Both have become accepted by scientists because they are supported by an overwhelming retinue of circumstantial evidence - in short, they explain a huge number of non-obvious findings elegantly and completely.

    We have much to learn about the details of greenhouse warming over the past century. It may be that there are additional factors, or that a more sophisticated version of the same theory based on new findings explains the observations even better (as Einstein refined Newton, and Morgan refined Darwin).

    However, the bullies in this particular equation are not the the supporters of mainstream science.

    In this case, the bullying is political, and it reeks of right wing politics.

    Kind of like the political activity of antievolutionist Bible bashers.
     
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  15. austingreen

    austingreen Senior Member

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    I just say gore! But really any time his name comes up now, whether pro or con, it seems political.

    +1
    This should be the sole standard of accepting a hypothesis like AGW. Unfortunately religion is trying to muscle in on science.

    Small correction, we have much to learn about global climate. When you state it as global warming, part of the null hypothesis is already corrupted. There are some very interesting questions that should be answered about ENSO and clouds and I hope that neither inhofe or jones suceeds in corrupting the studies.


    The first part is absolutely right. But we should be against this bullying whether it comes from the left or right, with good intention or bad. Let us stand up for science over the politics. No more denial of the temperature record, but also no more defense of over reaching conclusions like the rapid melting of Himalayan glaciers, with shout downs of the legitimate scientists that point out the evidence is wrong.

    Don't you mean the intelligent design bible thumpers that reject scientific method? Let's make sure they stay out of our school curriculum and government funded science. IMHO there is at least a plurality for that.
     
  16. TimBikes

    TimBikes New Member

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    I'm all for science....so where is the falsifiable hypothesis for AGW? When one argues that the science is settled and nearly every climate or weather event is "linked" to AGW, it ceases being science. It is the explanation for everything:
    warmlist

    So it becomes religion...Global Warming as Religion and not Science

    As for bullying, a right wing monopoly? Hmm....guess dabize has never heard of climate gate.

    And if it'll make you happy, I will retract Algore. Al Gore. Feel better?
     
  17. austingreen

    austingreen Senior Member

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    The problem comes into choosing your proxies and proper timescales. Alley has done a good job of summarizing the data, and if you have not looked at his work I suggest you do. If someone knows more about these proxies that would be a great addition to the discussion.

    I totally reject the notion that we should look only at 60 years, but many of the proxies are only good for a short period of time, and there will be disagreements. The dominant feature in global temperature is solar radiation, which is mainly effected by the intensity of the sun and the earths orbit around it. To explain differences between solar radiation and the temperatures on earth greenhouse gases have the highest correlation. The bulk of this work involves natural not anthropological greenhouse gasses. Cosmic rays are an old theory, but the proxies do not have nearly the correlation. This does not mean Svensmark's data is wrong. He simply has different proxies and more research is needed to reconstruct this data. He does give a sensitivity to greenhouse gasses within the relm of scientific reality they are simply at the low end, just as hanson is at the high end. Both of these are outside the IPCC estimates, but those bounds are a sumery and should not be taken as absolute limits. I would put Svensmark in the consensus of AGW, but instead of saying it is the majority cause he says 1/3 to 1/2. More research is needed to nail down this number, but the key one the sensitivity is more important than the blame.
     
  18. TimBikes

    TimBikes New Member

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    Re: chogan2's "elephant in the room" this is the correlation shown by the Danish Space Research Institute:

    [​IMG]

    You can read more here:
    Center for Sun-Climate Research

    I am admittedly no expert here and have not followed the climate debate as closely for a year or so now, but the GCR theories seem plausible, backed by data over long and short time periods and CERN has now recreated the physical mechanism, though I don't believe their work is yet complete to connect all of the dots to temperature changes, etc. & more recent temp. trending... also agree -as stated earlier- that I think there is a co2 climate link (AGW) so no dispute there. Primary issue is that based on all that I have read I think there are still many unknowns....
     
  19. TimBikes

    TimBikes New Member

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  20. SageBrush

    SageBrush Senior Member

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    ^^ Sorry, that denialist maroon position was good a decade ago, now it just sounds like a person trying to frame ideological stupidity as careful skepticism.

    Appropriate when statistical certainty of AGW is 60%.