Of Course Human Caused Climate Change Is Real

“In a survey last year by the National Academy of Sciences, 97 percent to 98 percent of climate researchers agreed with the premise that humans are causing climate change.” So says the Los Angeles Times, as quoted by (the addled1) Maggie Astor in International Business Times.

The first reaction of any scientist should be: what’s wrong with the other 2 to 3 percent? Given our knowledge of physics, it is not just true, but trivially and obviously true that humans cause the climate to change.

Climate Change to cause increase in warm sunny afternoons
Climate Change to result in increase of warm sunny afternoons

But then so do ants cause climate change, and their arch rivals the aardvarks. As do yellow perch and their meals the nightcrawlers. Any species that moves or engages in respiration, or in eructation after a good meal, changes the climate.

It would be impossible for them not to. Why? Because any move through the atmosphere changes its state, just as any exchange of gases changes the state, and any change of state of the atmosphere is a change of climate. And that is that. Humans, ants, and every other damn creature cause the climate to change.

The only question is how much? A worm wiggling across the surface of a sidewalk after a rainstorm is not moving fast, and thus not causing large changes of state of the atmosphere. But it’s not as simple as that: the birds who dive bomb the worms cause larger changes, changes that would not have taken place had the worms not been there.

And when the worm begins to rot after you squish it, its dissolving body changes the chemical composition of the atmosphere, and changes it in a different way than if it were processed through the gut of a robin.

Don’t scoff! We read that the biomass of worms outweighs that of humans. Worms are unimaginably important critters, aerating—get it?—soil, feeding fish, and crawling trillions of miles. How can we say authoritatively the exact effect worms have on climate? We cannot, not exactly; but perhaps we can approximate it.

To do that we need to define what the climate is. Despite what you hear from some unthinking sources, climate is weather. Climate is a statistical artifact, an averaging of variables. From moment to moment, all animates and inanimates, experience weather, which is a combination of temperature, moisture, pressure, radiation, and wind, which combined make up the state of the atmosphere.

This state is not static, of course, and changes on a scale too fast for the human eye to follow. We are forced to pick arbitrary moments in time to measure (with error) this state, and then average them. We call the result of this statistical operation “climate.” Sometimes we average the averages and call those super-averages climate. What an imperfect process!

To be clear: no thing experiences a climate, which is merely a statistic; yet all things experience weather.

Humans and worms do cause the weather to change, even cause it to change measurably; thus they also cause the average of the weather—the climate—to change measurably. For instance, your author lives on a small island upon which is dumped a great, tangled mass of concrete, through which scurry motorized vehicles, rats, cockroaches, and even people. These static and movable objects cause great changes in the weather, and thus in its average.

Humans, on the island and off, also pump various gases and other effluvia into the atmosphere. These gases also cause changes in the weather, thus climate. So much is indisputable.

What is disputable is how much. We can ask—it is an intelligible question—-what the weather (thus climate) would be like on the small island given the concrete, vermin, and people were removed. We might cobble together a mixed physical-statistical model which gives an answer. But the answer won’t necessarily be the right answer. And we’ll never be able to tell if it’s right or wrong because we’ll never be able to shift all that stuff off the isle to check.

We can also ask what the weather (thus climate) would be like if we were to slow, hold constant, or increase pumping carbon dioxide into the atmosphere. But we have the same problem as before: we’ll never know if the model is right because all we’ll have is the atmosphere that exists, and the knowledge that everything, from worms to the sun, cause changes in it.

A clue to model accuracy can still be found, though. If the model can make skillful predictions2 of new states of the atmosphere, then we might believe that it can tell us what the weather (thus climate) would be like if we were to make behavior changes.

But if it cannot make skillful predictions, then because we know of the vast complexities of the weather and its measurement, and of the near infinity of things that can, do, and might cause it to change, and of the oddities that go into averaging weather to create climate, we are right to not rely on the model and to cast a skeptical eye on its results.3

——————————————————————-

1There is scarcely anything in her article that is true. Astor, like many, favors the widely debunked Galileo myth over the reality. And she says things like, “you can’t prove that gravity exists”. What can’t be proved is our theory of what causes gravity. Only lunatics don’t believe it exists.

2A “skillful prediction” in this context is one which bests a prediction of “everything will be as it has been, more or less.”

3That’s all we can do in one column. For more, click “Climatology” on the left or “Start Here” at the top of the page.

41 Comments

  1. This is one of your most brilliant pieces.

    I’m quite skeptical that we’ll all bake, sizzle or drown (to the tune of Beg, Borrow or Steal any time soon, and that, should the unlikely become reality, that CO2 should prove to be our undoing.

    One particular argument we skeptics use is one I’d like to see retired. It goes something like this: Well, y’know, CAGW is only a theory, and by the way, so is Evolution. And I recognize, Dr. Briggs, that you did NOT use that argument.

    I’m not qualified to debate the accuracy of the argument, but I’m convinced it makes us look less aware of the very tenets about which we express skepticism. (Damn, that syntax better confess, and soon, given how I just tortured it.)

    And I strongly suspect that a scientific theory is very different from, say, one’s theory about why Aunt Agatha didn’t attend last week’s family reunion. (I think it’s because her “long-time companion” moved out, which saddened her into immobility. Others point to a marked increase in the frequency of her trips to the package store. I respond, a bit heatedly, that her enhanced spirit consumption is a cause, not an effect of her companion’s hasty departure.) All I’m saying is there are theories, and then there are theories.

    Anyhow, please disregard all save the opening line. What do I know? Don’t answer that, please.

  2. OK. Another reason springs to mind concerning Agatha’s recent absence, but that’s not important.

    Some say scientists themselves could be the very cause of climate modification due to their high, shiny foreheads and proclivity for the wearing of spectacles, which everyone knows reflect too much sunlight onto report writing paper, thus warming desk surface ambient temperatures by 2.0273± skoshes per febricity.

    I take the opposite view, however, and welcome attempts by the Maggie Astors of the world to put proven facts out before those of us in flyover country in order to better our lives and prepare us for a life of dhimmitude. Bless you, Maggie. We don’t deserve you.

  3. Mr. Briggs,

    Please stop trying to opine on a subject you have no idea about. The article above is pure nonsense, since you’re ignoring one basic fact: the AGW theory is not about an influence of humans as living, moving organisms on weather — I guess everybody would agree that this kind of influence is negligible. The theory is about humans moving large amounts of fossil carbon from its deposit sites to the atmosphere — and that’s something no other species has done before. And there’s nothing uncertain about the increase of energy radiated back to the surface caused by an increase in the amount of atmospheric CO2 (and other greenhouse gases). I assume you don’t want to fight thermodynamics, so — even leaving aside all feedbacks and the question of climate sensitivity — you must accept the ~1.6 W/m2 of the current radiative forcing we’ve produced by raising the CO2 concentration from 280 ppmv to 390 ppmv. So please stop telling cute stories about birds moving through air and worms rotting under a tree, and instead try to comprehend what ~800 trillion Watts of additional energy can do to planet’s climate system.

  4. Hi Grzegorz,

    You state: “The [AGW] theory is about humans moving large amounts of fossil carbon from its deposit sites to the atmosphere”. However, this is much too simplistic. See, for example, the following article:

    Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell, W. Rossow, J. Schaake, J. Smith, S. Sorooshian, and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union

    From the abstract:

    “Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.”

    You also state that Briggs should stop telling “cute stories” and “try to comprehend what ~800 trillion Watts of additional energy can do to planet’s climate system.” (Watts? Not CO2?) Comprehend how? You fail to note in your comment the overwhelming complexity of the climate system (the point of Briggs’ “cute stories”). This complexity means that comprehending the climate relies on the climate models. And this is explicitly addressed in one of the key paragraphs of Briggs’ posting:

    “A clue to model accuracy can still be found, though. If the model can make skillful predictions2 of new states of the atmosphere, then we might believe that it can tell us what the weather (thus climate) would be like if we were to make behavior changes.”

    How can the preceding paragraph be nonsense? Please have the courtesy to at least address the points Briggs actually makes. Some of Briggs’ postings make more sense to me than others. But I don’t follow his blog because he posts nonsense.

    George

  5. Grezgorz,
    Please, leaving aside (as you suggest), the questions of feedbacks and climate sensitivity, why don’t YOU tell us the effects of the additional energy on the climate. Also, you might want to check out the contribution of termites to the atmospheric CO2 level (since you imply only humans can affect it), and the effect of ocean temperatures on the CO2 level while you are at it.

    Uncertainties in climate models, and inadequate understanding of natural climate variations, makes climate prediction a fools game, until the science is vastly improved.

  6. If I recall correctly the whole of the mathematical theory of chaos and fractals arose from Lorentz’s attempt to model climate. I remember the ‘butterfly in Peking’ thing and the discovery that climate was a system with such a high sensitivity to initial conditions that long-term forecasting was a practical impossibilty. Does anyone know when that problem went away? Or was it enough to realize that the butterfly thing was just a cute story?

  7. So little is the actual warming that I would suspect if all trace of human activity and infrastructure were removed from the island, the thermometers could well reveal that ACO2 is cooling the atmosphere.

  8. Has anyone, anywhere given any evidence of any living planet having “climate stasis”? If not then climate change is normal. Controlling the climate, like controlling guns or anything else, has nothing to do with climate or guns. It is about control, pure and simple.

  9. spangled drongo says:
    11 September 2011 at 7:30 am

    the thermometers could well reveal that ACO2 is cooling the atmosphere.
    ##############

    The physics of co2 is very clear that it refelcts and transmits infrared.

    ##########
    Craig says:
    11 September 2011 at 9:22 am

    Controlling the climate, like controlling guns or anything else, has nothing to do with climate or guns. It is about control, pure and simple.

    ####################

    If we don’t move forward, what the far right fears the most will eventually have to happen. The least intrusive way to resolve this problem means starting now.

    ####################

    D Johnson says:
    11 September 2011 at 12:08 am
    Grezgorz,
    Please, leaving aside (as you suggest), the questions of feedbacks and climate sensitivity, why don’t YOU tell us the effects of the additional energy on the climate.
    #################

    http://www.skepticalscience.com/why-450-ppm-is-not-safe.html

    ###################

    Anthropogenic co2 will raise temp 1 deg centigrade by itself when we 560 ppm. Water vapor will increase about 7% resulting in a strong feedback influencing our temp higher2 more deg C. This is why the IPCC comes together to tell the world what they are observing in our climate.

  10. The computer climate models use a carbon dioxide residence time in the atmosphere of hundreds of years. Dr. Segalstad has measured the actual CO2 residence time in the atmosphere as about 5 years. His measurements are consistent with measurements made by others. The climate models are based on incorrect assumptions of carbon dioxide persistence.
    Go here http://www.co2web.info/ .

  11. “Climate is a statistical artifact, an averaging of variables.”

    Is that so? To me it seems equally valid to view climate as a set of random variables, and weather as a series of instantiations of these variables. Parameters of the climate system determine the probability distributions of the random variables. These distributions determine how frequently we observe particular parameters in weather.

    In other words, does weather cause climate, or does climate cause weather?

  12. Renewable Guy,

    “The physics of co2 is very clear that it refelcts and transmits infrared.”

    Except that you can’t measure the results.

    Apart from UHIs, in rural areas the increasing use of irrigation, particularly at night, raises temperatures considerably.

  13. Renewable guy says:

    11 September 2011 at 10:37 am

    D Johnson says:
    11 September 2011 at 12:08 am
    Grezgorz,
    Please, leaving aside (as you suggest), the questions of feedbacks and climate sensitivity, why don’t YOU tell us the effects of the additional energy on the climate.
    #################

    http://www.skepticalscience.com/why-450-ppm-is-not-safe.html

    ###################

    Anthropogenic co2 will raise temp 1 deg centigrade by itself when we 560 ppm. Water vapor will increase about 7% resulting in a strong feedback influencing our temp higher2 more deg C. This is why the IPCC comes together to tell the world what they are observing in our climate.
    ****************************************

    Renewable,

    But you have NOT ignored feedback as Grezgorz suggested. The extremely high feedback attributed to water vapor is conjectural to say the least. In fact, several studies are suggesting the feedback may be negative, when clouds are considered. And the actual temperature history in this century is more consistent with small or negative feedback. Seriously, can the IPCC be trusted considering their history?

  14. Grzegorz Staniak says:

    10 September 2011 at 7:33 pm

    Mr. Briggs,

    So please stop telling cute stories about birds moving through air and worms rotting under a tree, and instead try to comprehend what ~800 trillion Watts of additional energy can do to planet’s climate system.

    Watts are NOT energy. Watts are energy per unit time. Energy is the integral of Watts with respect to time. So I say to you: Try to make statements that have relevance instead of mixing apples and oranges.

  15. C’mon folks. The whole issue not yet determined is sensitivity, and nobody’s yet determined it. However, we do have some evidence. Svensmark’s theory makes more than a little sense, and more low cover clouds tend to cool, less clouds bring on more heat.

    That, in conjunction with the fact that there are numerous peer-reviewed investigations of the MWP clearly indicating it was as warm, likely warmer than now. New studies continue to arrive, and it’s quite clear that the MWP was global – not regional. No industrial activity back then, and CO2 was at its “standard” level of 280 ppmv. Then there was the fact that the current warming began around the mid 1600s, at the bottom of the ice age. That’s 200 years BEFORE our industrial period began. Again CO2 was at 280ppmv. Finally, CO2 has been rising steadily the mid 1800s, but temperature rise is not correlated. Most of the temperature increase since the 1800s has been from 1910 to 1940 and from 1975 to 1998. Temperature has been flat since then, and (by satellite measurements) actually cooling now for about a decade.

    Then there is the fact that CO2 has in the more distant past been 10 to 20 times as high, even during a couple of ice ages and going into one ice age. (Pretty obvious that the ice ages are not easily deterred, and we’re due for the next one.

    It would clearly not be prudent to permit politicians to impose the kind of drastic economic constraints based on no firm evidence. But, in any event, neither China, Russia, or India (plus all other 3rd world countries) are going to move their inhabitants into caves, so what the US and England and Australia do matters not at all.

  16. Mr. Briggs,

    This is an inaccurate portrayal of the current state of the science, as there is conclusive evidence that:

    -the increase in atmospheric CO2 since pre-industrial levels is anthropogenic [1]

    – the increase in temperatures is caused by the increase in atmospheric CO2 (based on satellite measurements of incoming and outgoing radiation) [2][3], and not the sun [4]

    furthermore, there is evidence that the estimate of radiative forcing by the IPCC is accurate[5], and the sea levels are rising.

    Thus the evidence for global warming does not rely on making a distinction between climate and weather or anything of the sort.

    1. http://www.bgc-jena.mpg.de/service/iso_gas_lab/publications/PG_WB_IJMS.pdf
    2. http://www.eumetsat.int/Home/Main/Publications/Conference_and_Workshop_Proceedings/groups/cps/documents/document/pdf_conf_p50_s9_01_harries_v.pdf
    3. http://www.agu.org/pubs/crossref/2009/2009JD011800.shtml
    4. http://rspa.royalsocietypublishing.org/content/463/2086/2447.full?sid=b80c9682-6905-463e-b689-47efd92d886a
    5. http://www.agu.org/pubs/crossref/1998/98GL01908.shtml

  17. Renewable guy, your numbers are off. A doubling of CO2 causes about 0.5C of warming in a gas chamber, and if water feedback increases that, I’ll eat my socks. Water vapor has a myriad of effects on the environment, some warming, some cooling. Analytical attempts to model this fail utterly due to the complexity of the planet. However, Le Chartlier’s principle clearly indicates that a system in equilibrium will move to counteract any force that is placed on it. While there are exceptions, I see no evidence that this is the case. It certainly has not been demonstated that there will be a strong warming from water vapor.

    So, let’s do some basic math.
    560 ppm – 0.5C warming
    1120 ppm – 1C warming
    2240 ppm – 1.5C warming

    At that point, we have literally burned all the fossil fuel on the planet, so going further is pointless. At 1.5C of warming, we can expect … well nothing much. 2C of warming is dwarfed by natural variation on a daily and annual basis. Increased CO2 and water vapor increase plant rainfall and growth plant growth. There will be a mild poleward shift of aerable land, and a noticable increase in growing season. There is no evidence whatsoever that adverse weather conditions will increase (models, schmodels, there hasn’t been an increase in hurricanes or tornadoes over the past century). In short, we have no great effects.

    On the other hand, people are starving due to biofuels, freezing/boiling due to energy shortages, and the poorest of the poor are killing their lungs with indoors cookfires.

  18. @George Crews
    Yes, “AGW is about fossil carbon” is a simplification, but “climate is just an abstract artifact, weather is chaotic, chaos can’t be modelled, so how can we possibly know whether our eyelash-batting in Brazil influences a tornado in Texas” is just plain wrong. Mr. Briggs may be a brilliant statistician, I’m in no position to judge that, but he doesn’t understand the reality of the science he attempts to opine on. There’s nothing abstract about the massive amount of energy radiated back to the surface by excess GHGs, and nothing chaotic or uncertain about a planet’s energy budget. Basic modelling of the increase in Earth’s temperature necessary to restore the thermodynamic equilibrium for a given increase in incoming energy takes less than a page of calculations. Go ask a physicist. You cannot just ignore that because you’re interested in painting a picture of uncertainty and doubt.

    @D Johnson
    Evaluations of the effects of the anthropogenic radiative forcing are taking place all the time, here you can see how the models fare in comparison with the instrumental record:

    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-8-1.html

    There’s no need to worry about “uncertainties” and “inadequate understanding” as long as simulations agree with observations.

    As for termites, they’re not a significant source of atmospheric CO2, you got it confused with methane. And anyway, as long as we’re not talking about excess GHGs, it doesn’t really matter. Carbon cycle had been practically perfectly balanced before the industrial age, so that any CO2 emitted by biosphere had been recovered from the atmosphere before. We are quickly creating a surplus of CO2 that just has to have a warming effect, unless you’re ready to invent alternative physics.

    @Rich
    Lorenz tried to predict weather, you’re confusing weather with climate here. You can’t reliably model the weather for your hometown at next Easter, but you can reliably predict the warming trend for coming decades given an increase in radiative forcing and a climate sensitivity factor.

    @Craig
    Ah, that’s a favourite straw-man in the denialosphere. Please refer me to a paper in reviewed scientific literature in which someone postulates a “climate stasis” for Earth.

    @Ray
    Dr. Segalstad actually hasn’t measured anything that hadn’t been known before, he just got a little lost in his excursion into climate science and confused particle turnover time with reservoir adjustment time. A carbon molecule may pass from ocean to atmosphere and back many times before the carbon reservoir adjusts itself to the increased concentration. Everybody knows turnover time is short, but adjustment time spans from 50 to 200 years, depending and conditions. Please open this:

    http://epa.gov/climatechange/endangerment/downloads/RTC%20Volume%202.pdf

    and do a search on “Segalstad”.

  19. @spangled drongo

    Except that you can’t measure the results.

    Yes, you can. We have measurements of increased longwave radiation to Earth’s surface, and decreased longwave radiation to space (measured from satellites). That’s empirical confirmation of increasing of the greenhouse effect. Also, UHI influence on temperature trends is negligible, since “bad” urban stations are accounted for and trends are adjusted accordingly.

  20. @Reed Coray

    Nice nit-pick, but irrelevant at the same time. There’s no denying that increase in longwave radiation towards the surface of Earth will rise temperatures — at least one degree per doubling of CO2 concentration. And if you postulate low climate sensitivity, you’ll have a huuuge problem explaining glacial-interglacial transitions.

  21. Grzegorz Staniak,

    You strike me as a non-scientist activist: the sort of person who memorizes some (in this case, irrelevant) statistics and trots them out to fill the air. That true? About being an activist, I mean.

    You have missed, perhaps willingly, the central, deeper philosophical and statistical argument about what is and what is not evidence for ascribing the change in a climate. Your welcome to comment, but try to keep on topic.

  22. Sven Tärpe,

    Be careful about reifing the math. Probability is used to describe our uncertainty in some thing and not to describe a causal mechanism.

    Climate, since we operationally define it as an average of weather, cannot drive weather. But changes in the moment-to-moment state of the atmosphere can changes the averages (i.e. climate).

  23. @Ben of Houston

    Well, you’d better go get some gravy to put on your socks then. If you assume a negligible feedback from water vapour, you cannot explain the ~5 K differences between a glacial and an interglacial in ice age cycles — the changes in incoming solar energy due to Milankvic cycles are just too small to explain them.

    Also, you’re kidding when you’re saying: “2C of warming is dwarfed by natural variation on a daily and annual basis”, right? 2C of warming is a big change (close to half the difference between glacials and interglacials), at the moment we’re having about 0.15 K per decade and this is a fast change. Remember that we’re talking about global mean temperature trends, diurnal and seasonal variability has nothing to do with them.

    And please check this list:

    http://www.skepticalscience.com/global-warming-positives-negatives-intermediate.htm

    before arguing that climate change of the magnitude that we’re observing will be beneficial.

  24. Mr. Briggs,

    I’m sorry, but I’m a bit too old to be impressed by your patronizing tone. Before you start to direct people to the topic, please learn more about the topic yourself. There’s absolutely no point in analyzing how humans may affect climate as they “move through the atmosphere” while ignoring a massive change in the energy budget of the planet that they cause by increasing the atmospheric concentrations of greenhouse gases. I’m afraid no amount of “deeper philosophical and statistical arguments” can make the empirical evidence of that change just disappear in a puff of smoke.

  25. 1. Is the world getting warmer (and by what measurement that is relevant to human needs)?
    2. If so, is it getting warmer at a rate or predictably moving to a level well outside the bounds of normal cycles (coming out of the Little Ica Age and all)?
    3. If so, is human agency causing it, or, more precisely, will cause it to continue to warm outside “normal” historical levels?
    4. If so, do we know, exactly, the mechanism by which human agency is doing this?
    5. If so, can we confidently predict the long-term social and economic costs of continuing in this way?
    6. If so, are those costs substantial enough to be of concern?
    7. If so, are there things we might do to reduce those costs to a more acceptable level?
    8. If so, can we estimate their social and economic costs in comparison to the “proceed as before” case?
    9. If so, are we reasonably confident that the cost/benefit of changing to a less-warming path are better than the cost/benefit of proceeding as before?

    As far as I can see, the answer to #1 is “Likely” and to all the rest is not even, “We don’t know,” but, “We haven’t really tried to find out.”

    When sound science can answer all those questions in the affirmative, with a high degree of reliability, I’ll listen.

  26. Grzegorz Staniak,

    Activist it is. This is induced from the manner you skirted away from addressing the central topic.

    Marty,

    Excellent string of questions. The certainty with which activists answer number 9 is always astonishing. But of course, the uncertainty must necessarily increase as you move along the chain—as in this is as provable as any mathematical theorem. If you find yourself with the same level of certainty in #9 as in #1 (where even the observational record is formed of statistical model reconstructions), you are dealing with ignorance, or willful misunderstanding, i.e. politics.

  27. Mr. Briggs,

    Of course it has to be anything that reduces your cognitive dissonance. I guess I’m lucky I’m not a “godless communist” or somesuch, a mere “activist” sounds very gracious, thank you.

    One would only expect that being a scientist, not an “activist”, you’d present an argument or two and not just close off the conversation with a bit of pidgeonholing. Your claims are simply false: we are able to unequivocally ascribe the observed climate change to human activities, and we can be very confident of the basic modelling: that’s physics, you know. Anthony Sinclair referred you to sources on that, there above, but somehow you’re more interested in fighting straw-men than responding to specific arguments.

  28. Oh yeah, Grzegorz is an activist, all right. Blind faith in models is a sure sign.

    “we are able to unequivocally ascribe the observed climate change to human activities”
    Nonsense. There has been no adequate proof of human cause. The “hot spot” that was supposed to be the “fingerprint” of AGW doesn’t exist in the data. Other “proofs’ turn out to be shams. I remember in 1998, Ben Santer published a paper where he “proved” human activity was the cause. It all hinged on one sentence: “assuming the climate models are correct” which we know are not correct.

    “we can be very confident of the basic modelling: that’s physics, you know”
    More nonsense. There are many feedback mechanisms involved in climate/weather, most of which are not known with any confidence. Clouds are the most important and the least know. These feedbacks are also physics and they can an do override the “known” physics.

    35 years of experience in modelling and simulation in thermodynamic systems has taught me that models are not reality and should never be trusted unless backed up by data. The climate models to date are refuted by data.

    “And if you postulate low climate sensitivity, you’ll have a huuuge problem explaining glacial-interglacial transitions”
    No problems at all. When you can have 10 to 20 times the present levels of CO2 during an ice age, that proves low sensitivity and essentially the irrelevence of CO2 to global temperatures. Since the causes of glacial-interglacial transitions are not known, postulating low sensitivity is irrelevent, so no problem…huge or otherwise.

    If you wish to continue beclowning yourself, have at it. The amusement factor is great.

  29. Grzegorz,

    The burden is now on you to show where, specifically, my argument is false. No equivocation or subject-changing. You have already forgotten that it is a premise that I unequivocally ascribe climate change to human causes. And to causes non-human. Thus your sole attempt at a counter argument fails before it leaves the gate.

  30. Mr Briggs,

    I’ve already said what’s wrong with your argument: you ignore physical realities of the science that you comment. You’re trying to smuggle a logical fallacy, starting with true premises: “a) any living organism influences weather/climate by causing small scale changes in the initial conditions of a chaotic system”, and “b) humans are living organisms”, and then drawing to a false conclusion “therefore c) human influence on climate consists of small scale changes in the initial conditions of a chaotic system”.

    You do mention “pumping various gases” into atmosphere, but you continue to use the context of “vast complexities of the weather and its measurement” as if they mattered in the modelling of Earth’s energy budget. For establishing the basic flows, they don’t. Thus the major human influence on climate is not really related to the “vast complexities of the weather and its measurement”, and it’s simply not true that “it’s disputable” how we influence the climat. We have caused the surface of the Earth to receive more radiation. No matter how hard you try, you won’t be able to deny neither this, nor the simple physical consquence of this: an increase in global temperature trends.

    And if you’re interested in the predictive power of models, please cast your skeptical eye at what Dr. Hansen predicted 23 years ago, and how well Dr. Lindzen fared in comparison:

    http://www.realclimate.org/index.php/archives/2007/05/hansens-1988-projections/
    http://skepticalscience.com/lindzen-illusion-2-lindzen-vs-hansen-1980s.html

    Now, whose work produced more skillful predictions? What models was it based on? What does this tell us about the models we should be trusting?

  31. @Jim Breeding

    O my, you’re mistaken on so many levels about so many things that it’s hard to decide where to start. All right, let’s go through it in order of appearance then:

    1) there’s a lot of independent empirical evidence pointing to the human fingerprints on the observed global warming, you can start at: http://www.skepticalscience.com/10-Indicators-of-a-Human-Fingerprint-on-Climate-Change.html and references you find there;

    2) the atmospheric “hot spot” allegedly being required for connecting the warming with human activities is a popular myth in the denialosphere, but not much more:
    http://www.skepticalscience.com/tropospheric-hot-spot-advanced.htm

    3) As for “sham”, see point 1) and try to find anything there you can prove to be a “sham” — hand waving and incantations do not impress me much, try to use arguments, preferably with references to reviewed literature;

    4) “Ben Santer” etc. — again, look at point 1); if you don’t know the evidence in favour of the AGW theory it really doesn’t mean that it doesn’t exist;

    5) We know the scale of the radiative forcing and the sign and error bars of most of the feedbacks, of which clouds by no means are the most important — don’t confuse water vapour with clouds; no feedback can “overrun” increased energy input to the system, and there’s no way for a planet that receives more radiation to lower its temperature: if you don’t know why, go back to school;

    6) climate models, while by no means perfect, at this moment are actually doing quite a good job simulating the instrumental period and are reasonably stable, see:
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-8-1.html
    before you comment on their quality, and you can also refer to the articles on Hansen’s predictions — if models are so bad, how come he was so close to observations 23 years in advance?

    7) see point 6) — climate models are not really “refuted by data”, even though they’re not perfect; it would be nice if you supported your claim with an example anyway;

    8) “10 to 20 times the present levels of CO2 during an ice age”? When? 300 mln years ago? For the last ~25 million years the concentrations of atmospheric CO2 have been lower than 500 ppmv: http://goo.gl/dazUC — and they also had been lower than today’s values for more ~2 million years;

    9) causes of glacial-interglacial transitions are known quite well, I really don’t think you may not have heard about Milankovic cycles.

  32. Grzegorz,

    Evidently you are ignorant of what the word “skill” means. I urge you to look this up—look at my publications, or look at others. Hansen’s predictions are not skillful. And neither, for that matter, aer Lindzen’s (though he doesn’t claim it).

    Just for the sake of curiosity, since you are obviously not in the “biz”, how did you come to care about this so deeply?

  33. Mr. Briggs,

    Your evading questions and ignoring arguments doesn’t even has to be a prediction, it’s a given. Perhaps it’s a law I didn’t know. And the strength of the subterfuges that you employ is disputable — you’re not even right by your own simplified definition of a “skillful prediction” given above.

  34. Grzegorz,

    Evading! Good grief. You haven’t answered a single query yet. You are determined to be obtuse and are more interested in debating and scoring points by quoting random statistics than in learning something. Come back after you learn what the technical definition of skill is. There are plenty of links among my papers.

  35. Mr. Briggs,

    Your “queries” so far can be summarized as:

    a) “are you an activist?”
    b) “where, specifically, my argument is false”?
    c) “how did you come to care about this so deeply?”

    Two out of three are off-topic (nice score), the third has been answered. Are you able to present anything even resembling arguments, or is pidgeonholing and patronizing all you’ve got?

  36. Grzegorz,

    I grant that you are a good debater, in the talk radio kind of way. Those were some of my queries, but all of the substantial ones you ignored or pretended were irrelevant.

    Now, it remains that you show exactly how my argument presented above is flawed. Your one attempt failed because you assumed I claimed something false. You also persist in evading learning what skill means, in the technical sense of a skillful forecast. Answer these, and we can continue. Keep posting silly ripostes and meaningless, or irrelevant-to-the-topic statistics, and I’ll ignore them.

  37. Grzegorz

    The issue is not whether greenhouse gases can cause warming, but how much. John Tyndall settled the first with lab experiments in 1859-1865 or so, and also calculated the second, as not much relative to atmospheric water vapour, a nearly 14 times more powerful absorber and radiator.

    Regression analysis of temperature change since CO2 measurements began in 1958 relative to atmospheric CO2 and H2O confirm that Tyndal was right, the H2O is a very statistically significant determinant of temperature globally, regionally, and locally, while [CO2] is never statistically significant anywhere.

    Greg, the data sets are available free of charge from GISS, CDIAC, and for the H2O, from ESRL-NOAA. Do it yourself and get back to us.

  38. Mr. Briggs,

    If you can point to any other relevant questions that you’ve asked, I’ll be glad to answer them.

    Frankly, the thought that you might actually need me to repeat for the third time what you got wrong in the article is a bit scary. It hasn’t changed in the meantime. You try to reduce human influence on climate to minute changes in the initial conditions of a chaotic system (weather), so that you can argue that in view of its complexity reliable modelling is not possible.

    Thus you ignore the fact that the human influence on climate, one which absolutely dwarfs the ones you talk about, doesn’t depend on the chaotic system of weather. It is external to weather. It consists of energy imbalance measured as net radiative forcing at the top of the atmosphere. And it’s relatively very simple to reliably model — it’s just physics, not weather.

    It’s actually funny how you accuse me of assuming a falsehood in your article — while I’ve described it three times already — while yourself assuming my ignorance of a detail irrelevant to the argument, just to assume the pompous posture of a teacher. You may be ingenious in inventing excuses for evading discussion, but I’m afraid it won’t magically turn a fundamentally flawed argument into something that makes sense.

  39. @Tim Curtin

    Have mercy on poor Ben of Houston, he’ll have to eat his socks if you prove that water vapour is capable of acting as a positive feedback for temperature rises.

    You’re aware that it can only act as a feedback, regardless of its potency as a greenhouse gas, right? That water vapour simply cannot drive global temperatures, because for given levels of temperature and pressure you cannot add more water vapour to the atmosphere? You’ll just produce some rain in a few days.

    Have a look at http://coelho.mota.googlepages.com/RadiationBudget.pdf — you find there the values of radiative fluxes from greenhouse gases: 75 W/m2 for water vapour, 32 W/m2 for carbon dioxide. Confirmed empirically e.g. here: http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm

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