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Unforced variations: Oct 2011

Filed under: — gavin @ 1 October 2011

Open thread for October…


409 Responses to “Unforced variations: Oct 2011”

  1. 1
    Pete Dunkelberg says:

    How much of the observed Arctic amplification comes from black carbon? Mark Z. Jacobson thinks a lot of it does. fat pdf.

    [Response: BC does have an outsize effect in the Arctic (because of the effect on snow albedo etc.), but BC levels have been dropping in the Arctic since the 1980s (collapse of communism, Clean air acts etc.), so whatever effect it is having is going down quite rapidly. There is more that can be done which would probably help, but I would not assign it a dominant role. Important, yes, but not dominant. - gavin]

  2. 2

    From the shameless self-promotion department, a couple of milestones I’d like to acknowledge (especially since I owe them, in part, to the interest of RC readers):

    My Callendar article just hit its 1000th page view:

    http://doc-snow.hubpages.com/hub/Global-Warming-Science-And-The-Wars

    It was preceded slightly by the (much older) one on Fourier:

    http://doc-snow.hubpages.com/hub/The-Science-Of-Global-Warming-In-The-Age-Of-Napoleon

    And the new articles on radiation in the atmosphere are off to a good start last month at the 100 page view mark:

    http://doc-snow.hubpages.com/hub/Fire-From-Heaven-Climate-Science-And-The-Element-Of-Life-Part-One-Fire-By-Day
    (The search for the “solar constant”)

    http://doc-snow.hubpages.com/hub/Fire-From-Heaven-Climate-Science-And-The-Element-Of-Life-Part-Two-The-Cloud-By-Night
    (Measuring surface- and back-radiation.)

    Thanks to all who’ve checked them out so far.

  3. 3
    Pete Dunkelberg says:

    Linda’s first CO2 experiment. An improved link over the one from J Bowers in another thread.

  4. 4
    caerbannog says:

    Dr. Mann has just responded to a particularly pernicious denier hit-piece in the Vail Daily — it deserves wider exposure, so I’m putting up the link to it here: http://www.vaildaily.com/article/20111001/EDITS/110939988/1021&ParentProfile=1065

    And here’s a link to the hit-piece that prompted Mann’s response: http://www.vaildaily.com/article/20110930/EDITS/110929829/1021&ParentProfile=1065

    Interestingly enough, all you will see there is this: “This is an invalid article or has been removed from our site.”

  5. 5
    Snapple says:

    Dr. Mann helped write one part of the 4th IPCC Report that received a Nobel Prize.

    Martin Hertzberg claims the IPCC science is false, but our government’s National Intelligence Council, which is made up of 16 intelligence agencies, accepts the IPCC science.

    Dr. Thomas Fingar, former Deputy Director of National Intelligence for Analysis said in his June 25, 2008 before Congress:

    “Our primary source for climate science was the United Nations Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report, which we augmented with other peer-reviewed analyses and contracted research. We used the UN Panel report as our baseline because this document was reviewed and coordinated on by the US government and internationally respected by the scientific community.”

    I think that’s a pretty helpful character witness.

    The NIC has (recently?)declassified and posted many studies on their site, which I describe and link to here.

    http://legendofpineridge.blogspot.com/2011/09/national-intelligence-council-impact-of.html

    Perhaps Cuccinelli would like to sue them, too.

  6. 6
    Pete Dunkelberg says:

    Way to go Mike Mann! Noteworthy is the comparison of caerbannog #4

    “Interestingly enough, all you will see there is this: “This is an invalid article or has been removed from our site.””

    with this:
    http://scienceblogs.com/deltoid/2011/09/court_finds_andrew_bolt_dising.php

  7. 7
    Snapple says:

    Here is how Hertzberg is described on another site:

    Dr. Martin Hertzberg is a long time climate writer, a former U. S. Naval meteorologist with a PhD in Physical Chemistry from Stanford and holder of a Fulbright Professorship. He is a co-author of Slaying the Sky Dragon – Death of the Greenhouse Gas Theory and a member of an international group of scientists calling themselves the Slayers.

    http://pindanpost.com/2011/06/12/more-media-nonsense-dr-hertzberg-demolishes/

    It’s hard to see how someone could have a PhD in Chemistry and not accept that CO2 is a greenhouse gas.

  8. 8
    harvey says:

    He’s a blow ‘em up man…

    http://www.explosionexpert.com/pages/1/index.htm

  9. 9
    Imbroglio says:

    @caerbannog: The magical disappearance of Hertzberg’s screed may be connected to the magic word ‘libelous’ in Mann’s response. I’m sure Mann has better things to do than sue for libel but perhaps someone at the Vail Daily decided that discretion was the better part of vilification. The article’s still in the Google cache at time of writing, though it will presumably disappear as soon as Google re-crawls the URL. But of course it’s nothing we haven’t seen a hundred times before. I’ve saved a copy to my own computer, mainly because I loathe the policy of quietly ‘disappearing’ embarrassing articles, as practised by some online publications: if you think you’ve made a mistake, stand up and admit it, don’t try to cram it down the memory hole.

  10. 10
    Imbroglio says:

    Apologies, I think the Google Cache link got chewed up. Here’s a short version: http://goo.gl/cyJWj.

  11. 11
    Edward Greisch says:

    Please sign my petition at http://wh.gov/gtV.

    “WE PETITION THE OBAMA ADMINISTRATION TO:
    Stop Global Warming by shutting down the coal industry.
    If we do not stop Global Warming [GW] now, the desertification will continue and increase. Some time between 2050 and 2055, the land surface will be 70% desert and agriculture will collapse. Collapses due to small climate changes have happened many times before. If agriculture collapses, civilization collapses. If civilization collapses, everybody or almost everybody dies. We must prevent this by shutting down the coal industry. Let the electric companies figure out how to make electricity without making CO2, as long as they do so. Set a time limit of the end of 2015 to reduce the CO2 from a power plant by at least 95%.”

  12. 12
    Edward Greisch says:

    Go to
    https://wwws.whitehouse.gov/petitions?utm_source=092311&utm_medium=graphic&utm_campaign=daily
    and start another petition. If you get 5000 signatures, somebody will pay attention to it. You have to get 25 signatures to get the petition to be viewable without going to a special URL.

  13. 13
    Pete Dunkelberg says:

    Trees have been helping us, says the New York Times.

    Scientists have figured out — with the precise numbers deduced only recently — that forests have been absorbing more than a quarter of the carbon dioxide that people are putting into the air by burning fossil fuels and other activities. It is an amount so large that trees are effectively absorbing the emissions from all the world’s cars and trucks.

  14. 14
    caerbannog says:

    I posted a diary about Mann’s Vail Daily piece over at dailykos.com, hoping that some folks there would pick up that ball and run with it — and run with it they did! The diary made the “recommended” list, and lots of folks must have taken up my suggestion to click on the “recommend” link over at Vail Daily. Mann’s piece has collected 170 “recommends” so far (about two orders of magnitude higher than the average number of “recommends” bestowed on a typical op/ed piece there).

    I’m not harboring any illusions about this making any significance difference overall, but what the heck — every little bit of “viral” marketing helps!

  15. 15
    Brian Dodge says:

    Dr. Hertzberg was a blow ‘em up man; according to his website he now “…serves as an expert consultant for attorneys involved in litigation related to accidental explosions and fires.”

    His statement “Knowledgeable scientists, including the more than 30,000 such as myself who have signed the Oregon Petition” (in the disappearing rant), and OISM’s lax standards as to who is a scientist, reminds me of a joke whose punchline is “”I don’t believe I’d a’told that one, brother.”

  16. 16
    Mike says:

    I’m covering related rates in my calculus course. I want to do an example for the students on the expansion of the Earth’s atmosphere as temperature rises. Let T be the ave temp, V be the volume, h the height (or depth) of the atmosphere and t be time. Then

    V=some function of T. T is a function of t. And we want to find dh/dt.

    But I don’t know what to use for V(T) or how to define h. Any suggestions? I need to keep it simple.

  17. 17
    Ray Ladbury says:

    Pete Dunkelberg, To me, the news about carbon sequestration by vegetation seems to be a double-edged blade. Yes, it has helped us out, but CO2 has continued to climb expoentially. And as temperatures continue to rise, and more of the planet descends into drought, and more topsoil is washed away in impulsive rain efents, this could become a substantial positive feedback in the carbon cycle. Bastrop County, TX may have been an excellent example of the type of feedback I mention.

  18. 18
    Hank Roberts says:

    > expansion of the Earth’s atmosphere as temperature rises.
    > … V=some function of T …

    Mike, I’m not a physicist, but I don’t think it’s that simple.
    Try this: http://www-das.uwyo.edu/~deshler/Atsc4400_5400_Climate/PierreHumbert_Climate_Ch1.pdf

  19. 19
    Pete Dunkelberg says:

    Ray, yes, much of the NYT article is about extensive tree deaths cause by beetles moving north in a warmer west coast environment and extensive tree deaths from fire drought and floods around the world.

  20. 20
    Septic Matthew says:

    11, Edward Greisch: Some time between 2050 and 2055, the land surface will be 70% desert and agriculture will collapse. Collapses due to small climate changes have happened many times before. If agriculture collapses, civilization collapses. If civilization collapses, everybody or almost everybody dies.

    Is civilizational collapse now on-topic?

  21. 21
    Septic Matthew says:

    Now is a good time to address this paper:

    http://www.princeton.edu/~gkv/papers/Padilla_etal11.pdf

    The authors estimate a most likely increase of 1.6K by 2080 if the atmospheric concentration of CO2 doubles gradually throughout that time span.

    Personally, I think that the transient climate sensitivity is the single most important quantity wrt climate change for public policy purposes. The authors provide one way to estimate it. Theirs is probably not the last word.

  22. 22
    dhogaza says:

    He is a co-author of Slaying the Sky Dragon – Death of the Greenhouse Gas Theory and a member of an international group of scientists calling themselves the Slayers.

    Even Judith Curry, with her tendency to keep an open mind to all things skeptical regarding climate science, has openly described this book as being horsepucky.

  23. 23
    Pete Dunkelberg says:

    Mike, you’re on the right track in that climate and weather are how familiar physical and chemical processes work out on a planetary scale. Having a planet in your equations complicates things a bit. Hank gave you a top notch University physics textbook reference. Understanding the Forecast [second edition any day now] aimed at non-majors is a gentler start. There is online material for both these books and others too isn’t there?
    http://www.realclimate.org/index.php/archives/2008/01/our-books/

    Here is a wonderful article explaining the basics back in 2000:
    Held and Soden 2000. Water Vapor Feedback and Global Warming. Annu. Rev. Energy Environ.

    [beware a notorious "journal" with a name like that but not an annual review]

    Now back to your original question: if all the complicating factors that are constantly changing are left out and if you settle for half an atmosphere, you could work with the 500 millibar height, where half the mass of the air is below, half above.

    Here’s another one that might work: use the Stefan-Boltzman law: radiating energy away goes up as the 4th power of temperature.

    Consider a 1 square meter surface receiving from 200 to 300 watts of energy as visible light non stop, and radiating the energy away (the only way for a planet to cool itself and just getting hotter forever). Look at delta T of the surface as the incoming watts vary. The outgoing radiation will be infrared.

  24. 24
    Geoff Beacon says:

    Excuse me for referencing my own blog posting but this is the only source of the preliminary work that Kim Swales and colleagues are doing on the elasticity of demand for household energy consumption. He has told me

    We have undertaken econometric work on the elasticity of demand for household energy in the UK. We get values of around 0.4 for the short run and over 1 for the long-run.

    If this preliminary result is borne out, it means that Hansen’s carbon fee can have dramatic results. I favour taxing carbon to subsidise jobs because it may be a policy easier to sell in the UK.

    I think it time that climate scientists grappled with economists because they have the power and many are climate ignorant.

  25. 25
    Hank Roberts says:

    http://www.theozonehole.com/arctic2001loss.htm

    Colder stratosphere -> loss of stratosphereic ozone –> new record low

  26. 26
    Richard Hawes says:

    Science Fiction Literary Assistance Required:-

    Although I have worked in the oil patch since 1974, my M.Sc. is in glacial geomorphology (as was to be my PhD before I had a bad hair day and fell off Albert Peak near Revelstoke), and so I am “climatologically aware”, if no longer “practising”.

    I am looking for the title and author of a science fiction short story from the 1960’s or 1970’s. This estimated time period is based upon the degree of technical understanding and technical development in the writing about computers, satellites and climate control.
    I read it in an American-published paperback compendium called something like “Greatest Science Fiction Short Stories, Volume 1 or 2”, which I purchased between 1972 and 1980. It has been lost in one of several packings and moves and unpackings.

    The time period, I think, is implied as being some time in the very near (geological) future, around 2500 CE. The location is on board a manned orbital space station that contains the computer and weather control systems that operate the weather on a colonised planet, not named, but somewhat like earth. The weather system has to be geo-engineered, or it will revert to the pre-human colonial conditions. This was uninhabitable for human life because of its’ extreme cold and storms (?). The computer is controlled by a single climate scientist / geo-engineering computer operator, who presumably is on rotation from “groundside”.
    The station is visited by … how best to describe him, a young man of the Bullingdon Club persuasion … from the planet, from “groundside”. There is a total social disconnection between the two people. The young man clearly despises the geo-engineering computer operator as being a scientist, a boring person with a boring and pointless life, a technoid. However, the young man also has some rudimentary computer skills, and perceives the climate control computer as just another toy. While the computer operator is elsewhere, the young man deliberately asks the computer a self-referential question as a malicious prank against the computer operator. In the story, there is absolutely no way out of the self-referential loop. Since the computer is focused on the question, it cannot control the climate, which starts to go irreversibly out of control. The young man tires of the prank. He tells the computer operator what he has done, and to stop the loop, so as to regain control of the climate. The operator replies that he cannot, because there is no means of breaking the self-referencing loop. The computer operator immediately knows full well what the young man has done. The young man begins to realise what he is responsible for. They stare at one another.
    End of story.

    The writing style, so far as I remember, was more Ray Bradbury than Isaac Asimov, but pithy. I have never forgotten the story. Needless to say, I want to find it again.

  27. 27
    Pete Dunkelberg says:

    Amazon has the second edition: http://www.amazon.com/Global-Warming-Understanding-David-Archer/dp/0470943416/

    But Dr. Archer, the price has jumped way up to $62.34 from the first edition $62.34 while the page count has gone down from 288 to 207. And that’s for a paperback. Most 200 page paperbacks cost less.

  28. 28

    Scientists have figured out — with the precise numbers deduced only recently — that forests have been absorbing more than a quarter of the carbon dioxide that people are putting into the air by burning fossil fuels and other activities. It is an amount so large that trees are effectively absorbing the emissions from all the world’s cars and trucks.

    This is the “residence time” vs “adjustment time” issue. The claim is that the residence time of CO2 is quite short because of carbon cycling but that the time it takes to migrate to deep sequestering stores is long. I came up with a model for this based on the master equation here: http://theoilconundrum.blogspot.com/
    The residence idea really has to be clarified because the skeptics are having a field day with it. The problem is that they don’t understand the mechanisms and by introducing some fundamental concepts such as diffusion, you can really squelch the concerns.

    If climate scientists aren’t thinking about it this way, then maybe you can learns something new.

  29. 29
    Pete Dunkelberg says:

    @ 25, loss of ozone:
    Canada had naturally taken the lead in tracking Arctic ozone, but now they don’t want to anymore, notes the Rabbet:
    http://rabett.blogspot.com/2011/09/lies-and-lying-liars.html

    USA could do better too notes ever lovin’ Romm:
    http://thinkprogress.org/green/2011/09/02/310920/breaking-news-obama-calls-on-epa-to-pull-back-ozone-standards/

    P S @ 27: oops on the book price. It went up from about 40 to about 60 bucks for a shrinking book.

  30. 30
    John Mashey says:

    re: Vail Valley Times
    We were just there at Vail a month ago, before Steve Schneider conference in Boulder.

    Small publications are easily vulnerable to such things, as discussed in part in poor science reporting. Small publications simply do not typically have the expertise to deal with such, but can be helped, or at least urged to avoid such things.

    Still, I suggest that we should praise VVV for being responsive, far more so than various much larger publications. They screwed up, but then acted decisively and ought to get creit for that.

  31. 31
    pjclarke says:

    The open-armed embrace of Dr Hertzberg over at WUWT is something to behold. One hopes we are witnessing a defining moment. As I write the Wattbots are searching the internet’s various caches for the original text with a view to reproducing it in full, complete with violations of the second law of thermodynamics and the defamatory codicils. Go for it, Anthony.

  32. 32
    Meow says:

    @21: Very briefly perusing that paper, I came upon Figure 13 and scratched my head. Every one of its PDF curves sums to > 1. What’s up with that?

    CAPTCHA: edorrow Colclough

  33. 33
    David B. Benson says:

    On the sci-fi theme, I’m finding Empress of Eternity by L.E. Modesett, Jr., despite some reviewers who didn’t care for it; it has a stong climate cycle component which is why I mention the fantasy novel here.

  34. 34
    Meow says:

    @21: On further reading, I see that the paper projects transient climate sensitivity forward to 2030, showing a handy 90% confidence interval in Fig. 6. The 2008 90% CI is 1.3K-2.6K, which p.15 says “is reduced by 45% by 2030″ by “assimilation of surface temperature data up to…2030″. Table 1 then gives the “most plausible” 2030 CI as 1.3K-2.0K.

    Which immediately raises the question: what “surface temperature data up to…2030″?

    Well, that turns out to be data satisfying the constraint, says p.17, that “the temperature increase between now and then is no more than expected with our currently-calculated sensitivity parameter.”

    Let me get this straight: the paper calculates a sensitivity parameter’s year-2008 CI using modelling based upon historical forcing and temperature data, then generates synthetic temperature data for the years 2008 (?)-2030 based upon that CI, then uses that additional data to derive a 2030 CI?

    I could well be missing something, but this seems circular.

  35. 35
    caerbannog says:


    As I write the Wattbots are searching the internet’s various caches for the original text with a view to reproducing it in full, complete with violations of the second law of thermodynamics and the defamatory codicils.

    I suspect that at this point, Hertzberg would much prefer that the defamatory bits remain buried. Unfortunately for him, his WUWT “allies” are determined to keep digging them back up.

    IIRC, there’s an old saying that goes something like “With friends like that….”

  36. 36
    Hank Roberts says:

    > Padilla et al.
    First hit in Google is “Cloud wars” at Climate Etc.
    judithcurry.com/2011/09/21/cloud-wars/
    http://scholar.google.com/scholar?hl=en&q=Padilla+et+al.+climate+sensitivity

  37. 37
    Richard Palm says:

    One of my online acquaintances is asking “What’s the control?” when testing predictions of anthropogenic global warming theory, and I’m not sure I know the answer. I assume that what he’s getting at is what are the results being compared to, in determining whether the data are meaningful?

  38. 38
    Lawrence McLean says:

    Re #36, Richard Palm,
    The question “What is the control?” regarding AGW, is either naive or sarcastic. The convenience of being able to perform experiments with controls is not available in many scientific areas, examples where this convenience is not available include Astronomy, Geology and Climate science. With these sciences, other techniques must be used to validate theories. That the convenience of experimental controls are not available in these Sciences does NOT invalidate them, it just makes them a bit harder and the Scientists involved need to be a bit smarter in order to be effective!

  39. 39
    Lawrence McLean says:

    #24, Geoff Beacon,
    Before any of the measures you suggest can be implemented, there is a battle that needs to be fought and won. That battle is to discredit the so called “Free trade” economic dogma that has infected governments worldwide. It even has its own police force (the World Trade Organization). Unless trade tariffs (which have unjustifiably been discredited by neoclassical economics) are implemented to protect the industries in those nations that implement the measures you suggest, then those measures will destroy the economies in which they are implemented.

  40. 40
    Septic Matthew says:

    32, meow: Every one of its PDF curves sums to > 1. What’s up with that?

    Each pdf has a peak > 1.

    35, Hank Roberts,

    In response to a paper that is in press you go to a blog? You did much the same when you decided not to read the 110 pp of AOAS that I referenced. Didn’t you?

    31, pjclarke,

    I agree. Hertzberg is an embarrassment.

  41. 41
    Septic Matthew says:

    34, meow: Let me get this straight: the paper calculates a sensitivity parameter’s year-2008 CI using modelling based upon historical forcing and temperature data, then generates synthetic temperature data for the years 2008 (?)-2030 based upon that CI, then uses that additional data to derive a 2030 CI?

    I asked the corresponding author if they would be willing to share code and data. Maybe after the paper is published.

    In order to make a prediction about 2030 some assumption about what happens between now and then is necessary. Consider other predictions for the rest of the century that also make such assumptions (e.g. point process model for volcano eruptions) and use parameter estimates from models. With their code, or another implementation of the nonlinear Kalman filter, other people can make complementary predictions based on complementary assumptions.

  42. 42
    Hank Roberts says:

    > What’s the control

    The planet without burning fossil fuel, which changed far less quickly.

    http://www.americanscientist.org/issues/feature/1999/4/rapid-climate-change/9

    “When we model previous switches in climate, we can compare the model to the results of real-world experiments recorded in ocean sediments and ice cores. But when we model the future, we have no empirical basis to judge the model’s accuracy. If we take no action until we are completely confident the models are correct, then the only use for the models will be to explain what happened. Our insistence on a tested model is part of the reason society is continuing to conduct the largest experiment ever done, the experiment of increasing the atmospheric concentration of greenhouse gases.

    It will be another 20 years before the climate changes that are predicted to be associated with the greenhouse effect become large enough to be unambiguously differentiated from naturally occurring variations in climate….”

    ——

    As my dentist puts the same concept:
    “Brush only the teeth you want to keep.”

  43. 43
    Hank Roberts says:

    PS for Richard Palm — point your online acquaintance to:
    http://www.aip.org/history/climate/co2.htm

  44. 44
    Edward Greisch says:

    http://books.google.com/books?id=JihhbdpO-yoC&pg=PA144&lpg=PA144&dq=%22Organized+Climate-Change+Denial%22+mccright+dunlap+oxford&source=bl&ots=mTaCbrS_9e&sig=6AvQabli6J_t68Csb7CCGiWffT8&hl=en&ei=OK6ITqn9HYPk0QGKo53EDw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCAQ6AEwAA#v=onepage&q&f=false

    Climate Change and Society

    Page 40: The IPCC was formed….to blunt the activism that was beginning to emerge in the scientific community.

    Ah Ha! So RC is afraid of activism for fear of a repeat of something or other that the rest of us don’t know about. Tell us the whole story so that there will be too many people who know….

  45. 45
    Darv says:

    Richard Hawes @ 26
    “The Monkey Wrench” Gordon R. Dickson in “The Penguin Science Fiction Omnibus”. Aldiss, B. ed 1973
    I bought my copy new in 1987 so good second hand numbers should be available.

  46. 46
    Matt McIrvin says:

    A more sophisticated variant of the “no global warming since 1998″ meme seems to be developing: it’s something like “statistically significant cooling since 2001 or 2002″, based on curve fits to satellite measurements. The people pushing this don’t seem to have any specific alternative climate hypothesis they’re advocating, it’s more pure sowing of doubt based on a fairly short run of data, but at least they don’t seem to be depending on the 1998 maximum any more to drive the trend they’re claiming.

    Anyway, it’d probably be good to have a FAQ on this.

  47. 47

    #36–

    I think so.

    Some folks want to hang doubt on mainstream climate science by reifying the controlled lab experiment as the only ‘real’ way to do science. Of course, this rules out climate science since, as your friend’s question says (and as frequently expressed by many) “we don’t have a spare Earth or three lying about.” Hence, the thought goes, we can’t possibly know anything about the topic. . .

    Climate science is a huge topic. And some subfields do, in fact allow experimentation. For instance, John Tyndall’s work uncovering the greenhouse properties of CO2, water vapor, and other gases, was done (very elegantly, too) in the lab. That’s probably the most famous example, but I’m sure that there are others one could cite.

    But many sciences–both under and out of climate science ‘umbrella’–are not particularly amenable to the controlled lab experiment–or at least, not as the only way of learning anything. Many sciences require something called ‘field work,’ where the scientists go out into the real world and measure things in situ. It can be tough, it can be tedious, it can be messy, and it can be a challenge to isolate the thing you actually want to measure–but it can be, and is, frequently done. (Think of ecologists, biologists, and glaciologists, to name just three fields.)

    (By the way, “in situ” measurement was the topic of my “Fire From Heaven” articles, linked at the top of the thread–there is now roughly two centuries worth of efforts to measure radiation and heat transfer in the atmosphere, just a small portion of which I sketched in those two pieces.)

    Such measurements can be combined with careful analysis to build up a logical, coherent picture of how the climate system works. There are ways to approximate experimentation: one observes the changing inputs that Nature gives you: what happens to weather when a large volcanic eruption occurs? What happens when the solar minimum comes round, and is especially low? (A current ‘experiment’ now coming to an end, apparently.) What happens to weather when the Arctic sea ice has four years of very low summer minima in a row? (Another current “experiment.”)

    You may also be able to see how the system worked in more widely-varying conditions in the deep past: what happened when the Panama isthmus closed? What sorts of climatic conditions are associated with extremely high CO2 levels? Do climatic conditions sensibly correlate with Milankovitch cycles of insolation changes?

    Finally, of course, you have the GCMs–the ‘virtual Earths’ that come closest to allowing controlled experiments on a planetary scale. Model experiments are the current (and likely, future) gold standard for attribution studies–if you can build a simulation based upon physical principles that reproduces a past climate, you can then vary the ‘virtual CO2′ or ‘virtual aeorosols’ or ‘virtual sunlight’ and see what happens. It’s precisely because the model runs are so convincing as experiments that denialists spend so much time attacking their validity. (For most of these folks “unvalidated models” appears to be a single word–even though every model goes through a validation process.)

    In summary, there are many “controls”:

    –For the whole system, we have modeling and paleoclimatic data.

    –For atmospheric, oceanic, and terrestrial processes, we have in situ measurement and remote measurement (ie., satellite sensing), combined in some instances with lab experiments.

    –For basic physical properties, we have lab experiment, verified by in situ and remote measurement.

    The demand for a single “control” is much too simple, radically underestimating both the scope of the problem, and the depth and breadth of the knowledge already acquired.

  48. 48
  49. 49

    #45–

    Yes. This tactic has a history by now. See my article:

    http://doc-snow.hubpages.com/hub/When-Did-Global-Warming-Stop

  50. 50

    #45 and my (as yet unmoderated) response–I should have added that I’m always on the lookout for updates, so if you have specific examples in mind, I’d very much appreciate a pointer!


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