It’s Not Zero

I have been meaning to link to this post for a while, but the Reference Frame, along with Roy Spencer, makes a valuable point I have also made for some time — the warming effect from man’s CO2 is not going to be zero.  The article cites approximately the same number I have used in my work and that was used by the IPCC:  absent feedback and other second order effects, the earth should likely warm about 1.2C from a doubling of CO2.

The bare value (neglecting rain, effects on other parts of the atmosphere etc.) can be calculated for the CO2 greenhouse effect from well-known laws of physics: it gives 1.2 °C per CO2 doubling from 280 ppm (year 1800) to 560 ppm (year 2109, see below). The feedbacks may amplify or reduce this value and they are influenced by lots of unknown complex atmospheric effects as well as by biases, prejudices, and black magic introduced by the researchers.

A warming in the next century of 0.6 degrees, or about the same warming we have seen in the last century, is a very different prospect, demanding different levels of investment, than typical forecasts of 5-10 degrees or more of warming from various alarmists.

How we get from a modest climate sensitivity of 1.2 degrees to catastrophic forecasts is explained in this video:

  • Andrew

    One teeny objection-a lot of your arguments for negative or no feedback are from the “electrical engineering” perspective on feedback. As Spencer points out, climate scientists have redefined the terms on poor electric engineers:
    There are good arguments to be made against high positive feedback, but “instability” isn’t one of them.

  • Hunter

    Don’t expect him to learn, Andrew; he’s trotted out this nonsense time after time after time, ignored the obvious idiocy of it time after time after time, and I’d wager it will be no more than two weeks before he plugs his ridiculous video again, apparently without the faintest idea that it’s all based on catastrophic misunderstandings.

  • kuhnkat


    when you claim ridiculous, do you mean like the IPCC idea that the climate system is dominated by positive feedbacks, yet, the earth has gone from a Greenhouse with much higher average temps and CO2, to the current glacial epoch????


    PS: don’t bother posting your ridiculous refutation. We’ve all read it many times.

  • Alan D. McIntire

    John Daly pointed out that the true net feedback may be about 0.2 C, based on the argument that
    the net greenhouse forcing is about 150 watts, global temperature increased about 33C due to that net feedback, and 33/150 =0.22C/watt.

    From Trebeth’s figures, there’s an additional 22 watts eaten up in convection, and 78 watts in latent heat for water vapor, so the actual figure may be 250/150 *0.22C= 0.37C with 40% of the heat being absorbed in latent heat and convection.

  • Eric K.

    I’ve been following many of the discusions on both climate skeptic and climate audit, but this piece provoked a line of thought that has been scratching at the back of my mind for some time.

    I was taught the scientific method in a cursory style in high school in 1963. And what stayed with me was that the most accurate descriptions of the interactions of variables would be through experimentation. In the case of CO2 at various altitudes, concentrations and as other variables as could be scientifically controlled would be defined so as to describe the effects of as they related to the expected results.

    Instead I find that the promulgaters of the global warming theory seem to rely on statistical models that can indicate correllation but not causation.

    I thank you folks at this site for trying to keep the GW “card sharps” honest, but where is the observation and experimentation that might define the true situation?

  • Jacob

    I second Eric K’s remark.
    I think it would be fairly simple to devise an experiment to measure the greenhouse effect empirically.
    Take a pipe, isolate it, fill it with a controlled atmosphere, containing various measured concentrations of CO2 and water vapor. Beam a long wave (infrared) beam trough it. Measure the intensity or energy of the beam at the other end of the pipe. Measure the temperature of the pipe and the air in it.
    Sounds simple to me.
    Has anyone done this? Could anyone point to a paper describing the results of such an experiment? If not – why not ?

  • Hunter

    Pretending that fundamental research simply never happened seems to be a bizarre new tack taken by deniers. Perhaps by affecting a spectacular ignorance of history you think you can somehow ignore the scientific understanding that has been painstakingly arrived at. Experiments like the one you wonder about were carried out a century and a half ago.

    Did you think to search for such a paper before you asked after it? If not – why not?

  • hunter

    whoever you are, just because I am away for awhile does not mean you get to use my name as part of your acting out.
    The lack of apocalypse is the best evidence for the failure of the models. The lack of heat in the oceans is a great clue as to why it is never going to happen.
    The fallacies of the AGW system are endless but the beleif is just too good to be false, for the belief based community.

  • anon@work

    It could be zero if the system saturates (more CO2 than IR photons) at levels lower than the current one.

  • Jacob

    Thanks for the link. I get a “file corrupted” message, but I looked up Tyndall.
    He also probably confirmed, by laboratory experiment, that the heat absorption of CO2 increases by a logarithm function as the concentration increases.
    This shows that there probably cannot be a runaway, infinite heating due to the CO2 greenhouse effect. The heating is limited in magnitude and is going to top at some level.

  • An Inquirer

    Jacob and Erik K:

    There are some phenomena which are well suited for laboratory experiments, and some which are not. Laboratory experiments require the ability to isolate the relevant variable, control the other variables, and implement procedures that are verifiable and repeatable. Think of the economic debate between supply-siders and Keynesians. Both point to the Kennedy tax cuts as proof of their positions with Keynesians maintaining that consumers increased demand with increased disposable income and supply-siders arguing that the tax cuts led to increased motivation, more capital, and better technology which lead to increased supply. We can’t isolate key variables and repeat the experiment. (The Reagan tax cuts and Bush tax cuts again led to economic growth, but again key variables are not isolated. Supply-siders argue that the surge in government spending in the late 60s & 70s did not seem have a similar impact on economic growth, but Keynesians argue that the variable of increased energy prices was not controlled.)
    In climate issues, both sides agree that under laboratory conditions doubling CO2 from preindustrial levels would lead to a one degree increase in temperature and that the impact is logarithmic. (Perhaps, we would not be greatly concerned about a one degree increase; perhaps the natural variability is more.) However, there are issues that we cannot get into the laboratory experiment – water and air convections, cloud formations, flora response, and other feedbacks – to name just a few. Global warming pessimists accept that CO2-induced warmer temperatures will cause a positive feedback via increased water vapor in the air. That is an intuitive thought and would cause temperatures to rise by more than the one degree. However, that feedback is not replicated in the laboratory experiment, and there are some scientific observations that run counter to the intuitive thought. Moreover, laboratory experiments will not tell us whether a small rise in temperatures will have overall beneficial or harmful impacts. Increased crop production and lower mortality rates have been associated with higher CO2 levels and warmer past temperatures, but we could hypothesize all sorts of negative impacts from warmer temperatures, and maybe we do not need to hypothesize – think of the 1930s. Therefore the question about laboratory experiments is a good one, and one that neither side is afraid of, but not one that resolves the argument.

  • Hunter

    “This shows that there probably cannot be a runaway, infinite heating due to the CO2 greenhouse effect”

    And who the hell ever claimed there could be?

    An Inquirer – water vapour feedback is observationally confirmed. See for example:

    * Soden et al. 2002, Science, “Global Cooling After the Eruption of Mount Pinatubo: A Test of Climate Feedback by Water Vapor”
    * Dessler et al. 2008, GRL, “Water-vapor climate feedback inferred from climate fluctuations, 2003-2008”
    * Gettelman & Fu, 2007, J. Climate, “Observed and Simulated Upper-Tropospheric Water Vapor Feedback”

    You didn’t specify which observations you think “run counter to the intuitive thought”. I wonder why not?

  • Jim

    Hunter: While I understand why water vapor is deemed a feedback in that is does contribute to the variability of warming, to stop there is very misleading. Water vapor is a strong greenhouse gas and in most of the atmosphere, it is by far the GHG with the highest concentration. It is overwhelmingly the dominant forcing, in the climate con man’s sense.

  • Andrew

    Hunter, I suspect he is speaking of the Radiosonde reanalyses of humidity. Since I have probably set off your “ATTACK!” alarm by mention that I merely think this is what he means, I will stay out of this one and let you hash out your discussion of what observations are kosher and which not with someone else. Seeing as you are a paranoid kook and all that.

  • An Inquirer

    In addition to the following research articles raising questions on linking CO2 increases to water vapor increases, there is the unresolved question of how clouds will react and influence climate as CO2 increases.

    “WATER VAPOR TRENDS AND VARIABILITY FROM THE GLOBAL NVAP DATASET” by Thomas. H. Vonder Haar1, John M. Forsythe, Johnny Luo, David L. Randel and Shannon Woo

    “Ocean water vapor and cloud burden trends derived from the topex microwave radiometer” by Brown, S.; Desai, S.; Keihm, S.; Ruf, C.

    ‘Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data’ by Garth Paltridge, Albert Arking and Michael Pook

  • JR

    If climate sensitivity is less than the IPCC says then why is the melting of the summer Arctic sea ice accelerating and proceeding much faster than the worst case IPCC models? Or do you dispute the albedo effect as well?

  • JR

    Have you seen this? It’s the first 20 minutes or so of a new documentary about ocean
    acidification entitled, “Sea Change” ( ) It was
    shown this week at the European Geosciences Union 2009 meeting
    followed by a press conference by relevant scientists. You can see the
    film clip and press conference here.

    It’s a must see.

    Do you debate the increasing ocean acidification too?

  • Jim

    I don’t see that the sea ice is melting all that fast …

  • Jim

    Maybe the loss of extent is slowing due to this …

    Arctic temps are getting cooler … err … colder.

  • Jim