The Sky Is Falling Less?

A new climate study suggests global warming may not be as dire as predicted.


Last week, Science published a new study by Oregon State University researcher Andreas Schmittner and colleagues who found that an increase of carbon dioxide in the atmosphere may result in less warming than predicted. The researchers declared that their results "imply less probability of extreme climatic change than previously thought." Has the global warming apocalypse been called off?

Researchers know from physics that added carbon dioxide tends to increase the temperature of the atmosphere because it blocks the escape of heat from Earth into space. The term climate sensitivity conventionally refers to how much warming can be expected from a doubling of carbon dioxide concentrations in the atmosphere. It is generally agreed that by itself, doubling the amount of carbon dioxide in the atmosphere above pre-industrial levels would boost the average global temperature by about 1.2° Celsius (2.2° Fahrenheit). However, many climate researchers believe that other feedbacks (water vapor, clouds, etc.) add to the effect of carbon dioxide (and other greenhouse gases).

As humanity has burned fossil fuels, carbon dioxide concentrations in the atmosphere have increased from 280 parts per million (ppm) at the beginning of the Industrial Revolution to 389 ppm today. Temperature records agree since the late 19th century that the average global temperature has increased by 0.8°C (1.4°F).

The question of climate sensitivity has long been a vexed scientific problem. With regard to climate sensitivity, in 2007 the Fourth Assessment Report of the United Nation's Intergovernmental Panel on Climate Change (IPCC) estimated that "climate sensitivity is likely to be in the range of 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values." In IPCC parlance, likely means that there is a 66 percent probability that climate sensitivity falls between 2 and 4.5°C (3.6 to 8.1°F), with 3°C (5.4°F) as the best estimate.

Even more problematic is that previous researchers have been unable to rule out that doubling atmospheric carbon dioxide will not produce even bigger increases, say, in excess of 6°C (13°F), in global average temperature. Researchers have tried to pin down climate sensitivity by analyzing recent observational climate data, by tuning climate computer models to see how accurately they reproduce past climate, and by comparing paleoclimate data to current conditions.

The Science study combines paleoclimate data from the Last Glacial Maximum 21,000 years ago with computer modeling to arrive at a lower climate sensitivity figure. They estimate that climate sensitivity likely (66 percent probability) ranges from 1.7 to 2.6°C (3 to 4.7°F) with a median estimate of 2.3°C (4.1°F). The even better news is that the study finds that climate sensitivities larger than 6°C are "implausible." If carbon dioxide levels double, the world will likely get warmer, but not catastrophically hot. In other words, the article suggests that the sky is falling less.

The new study achieves this result by doing several runs of a moderately complicated climate model plugging in various values for climate sensitivity. The researchers then checked to see if the model outputs matched their new set of paleoclimate temperature data involving 435 temperature proxies, 322 ocean proxies, and 113 land proxies. Proxies like the prevalence of certain kinds of plankton fossils in ocean sediments and pollen on land. Plugging in a 6°C climate sensitivity produced a snowball Earth entirely covered with ice which clearly didn't happen whereas inserting values below 1.4°C generated too warm a world.

Naturally, the new paper landed in the midst of the fraught debate over man-made global warming. The editors at Investors Business Daily assert that "it's a bombshell—another in a long line of revelations showing the scientific fraud at the heart of the anti-global [sic] warming movement." On the other hand, climate change alarmist Joe Romm at the Center for American Progress headlines, "Media Misleads On Flawed Climate Sensitivity Study."

Of course, every study can be criticized and this one is certainly no exception. One of the reasons that comparing the Last Glacial Maximum to today is scientifically intriguing is that atmospheric carbon dioxide levels 21,000 years ago were only 190 ppm. Schmittner and his colleagues attempt to work backward from Ice Age temperatures to estimate climate sensitivity.

One of the chief criticisms lodged against the new study is that it significantly underestimates how cold the Last Glacial Maximum was. According to the new study, during the Last Glacial Maximum, the world was on average about 3.3°C (6°F) colder than today. In contrast, the IPCC estimates that Ice Age temperatures were between 4 to 7°C (7.2 to 12.6°F) colder than today. A colder Last Glacial Maximum implies higher climate sensitivities due to lower levels of atmospheric carbon dioxide. So figuring out which temperature regime is the more accurate is critical to determining the validity of the new study's estimates.

Another possibility suggested by a Science Perspective by University of Edinburgh researchers Gabriele Hegerl and Tom Russon published simultaneously is that adding carbon dioxide to a colder Ice Age climate will affect different climate feedback mechanisms. If so, adding carbon dioxide to our warmer interglacial climate will yield a different (and perhaps higher) climate sensitivity.

Assuming, however, that the new study's results stand up to further scrutiny, what does this mean in terms of future climate change? At the United Nations' Cancun climate change meeting last year, climate negotiators set a goal of avoiding an increase of more than 2°C (3.6°F) above pre-industrial temperatures. The folks over at the RealClimate blog calculate that if the IPCC's climate sensitivity estimate is right, at current rates of carbon dioxide increase this goal will be exceeded in 24 years. Assuming the new estimate is right adds 11 years.

"It is rare that a single paper overturns decades of work," notes Nathan Urban from Princeton University in a New Scientist interview. Urban, a contributing author to the new study, modestly added, "Quite often, it turns out that it's the controversial paper that is wrong, rather than the research it hopes to overturn. Science is an iterative process. Others have to check our work. We have to continue checking our work, too." 

If their work ultimately checks out that would mean that while the world will get warmer, it will likely not become catastrophically hot. In other words, the sky would be falling less. 

Ronald Bailey is Reason's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is available from Prometheus Books.


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  1. In other words, the sky would be falling less.

    Yes, but if only half the sky falls, what will hold the other half up?

    1. Al Gore’s sense of self-importance?

      1. He who is the Oracle who informed the unwashed masses that the interior of the earth is hotter than the sun!

        1. Really now, a world inhabited by someone who could allow that to slip from thier lips, is not a world worth saving. Carbon Dioxide, take us away!

          1. What a wonderful incarnation of a Calgon reference.

        2. That was a Fox News Photoshop job.

        3. He matches up nicely with the average American IQ.

    2. Well at any given time half the sky is beneath us, so naturally gravity would pull it away from the underside of the Earth. If it broke loose, it’d probably just crash into Hades.

  2. I thought it was reasonably well established that CO2 alone had a diminishing effect, and that it wouldn’t result in much more than about a 2 degree centigrade increase.

    Most of the OMG AGW comes from positing various feedback loops that exacerbate the CO2 effect.

    1. No, most of the AGW comes from Hydronium Hydroxide. It is a well known secret and the science is settled.

      1. I believe it is dihydrogen oxide.

        1. Actually, its hydrolic acid.

          1. Actually it’s hocus pocusium

            1. Dude, its a nomenclature game.

              1. He obviously never had a Gilbert chemistry set!

    2. I thought it was reasonably well established that CO2 alone had a diminishing effect, and that it wouldn’t result in much more than about a 2 degree centigrade increase.

      I’ve been hearing “ocean heat sinks” which suddenly decided to start sinking heat last decade.

      1. For which, of course, there is zero evidence.

        That’s typical for these guys. When the facts don’t fit the theory, they try to change the facts with pure speculation.

    3. I thought it was reasonably well established that CO2 alone had a diminishing effect

      Yes. The theory is that CO2 traps infra red energy and there is only so much that can be trapped until it is all trapped. Any increase in CO2 after that point cannot heat the earth more as all the heat (the IR type of heat) will already be trapped.

      The rest of the warming that the warmists say will come will be from increased water vapor…which is also a “green house” gas.

      Of course if CO2 already traps all the heat then what the fuck is the water vapor going to trap?

      1. Joshua,

        CO2 and water have overlapping, but different absorption bands across the IR spectrum.…..ission.png

        So, the relationship between the two is complicated to say the least.

        1. Comparing those absorption bands one wonders why H2O which covers a huge area of the band has not already caused run away global warming on a planet that is mostly covered with water.

          But yes I see your point…of course your point only open an even bigger can of worms.

          1. “has not already caused run away global warming on a planet that is mostly covered with water.”

            When the sun goes down at night does the temperature fall to -200?

            Water vapor already traps in a lot of heat.

      2. The diminishing effect only makes sense if the amount of CO2 is fixed. That is to say, a given amount of CO2 can only hold so much heat. However if more CO2 is entering the atmosphere then the heat-retention capacity gets greater.

        1. That’s not true. It’s not really heat that CO2 absorbs, it’s infrared radiation, which is a type of light that’s not visible to the eye because it has a longer wavelength.

          The critical point is that CO2 absorbs only certain wavelengths of IR radiation. If all the IR radiation at those wavelengths is being absorbed by the CO2 already in the atmosphere, additional CO2 will not absorb more IR radiation.

          Consider an analogy with visible light. Imagine a glass of water to which you add red food coloring. Adding a little bit results in light color, maybe a pinkish color. Continuing to add more food coloring will result in a darker color. However, there will come a point where adding more food coloring will not make the water appear any darker.

          The reason is that the food coloring is red because it absorbs other colors of light and transmits red light. If there is sufficient food coloring in the glass, it can absorb ALL of the light of other colors that’s passing through the glass. Therefore, additional food coloring will not make the glass appear darker. The analogy to CO2 is direct because the color of visible light is determined by its wavelength. The food coloring, like CO2, absorbs only certain wavelengths of light.

  3. “Quite often, it turns out that it’s the controversial paper that is wrong, rather than the research it hopes to overturn. Science is an iterative process. Others have to check our work. We have to continue checking our work, too.”

    This must be his first time doing climate science. We all know the science is already settled.

  4. Seeing as how this has long been obvious to anyone who knew what the IPCC’s CO2 climate sensitivity values predicted for the current temperature, I predict that this paper will have several half-assed rebuttals, and then be promptly ignored just like they’ve been ignoring the thermometor for the last decade.

    1. Is Thermometor a supervillian with the power to determine the temperature?

      1. In the current political climate, that would indeed make him a villian.

    2. the IPCC? isn’t that the U.N. group that swore the Hymalayan glaciers were melting based on what turned out to be a half-assed article in some magazine that was cooked up in the writer’s eco-terrorist mind?
      why on Earth would someone even consider using articles published by this agenda driven pigsty unless, of course, there is some money in it…

      1. Because there is a LOT of money in it. And power, never underestimate the allure of power.

  5. Reality is politicizing the debate.

    1. That’s just because the facts are biased.

  6. The researchers declared that their results “imply less probability of extreme climatic change than previously thought.”

    What’s this? Good news?


    1. No! Burn the witch! She turned me into a Newt.

  7. This should help simplify things for those who aren’t so good at envisioning logarithmic functions in their heads:


    Conclusion: If climate sensitivity were around 3.0, as claimed by alarmists, we should have observed 2.5x more warming since the industrial revelution than we actually have.

    Alarmists’ response: But…aerosols! And we can’t observe all the warming because the heat is trapped deep in the ocean! The science is settled, and if you disagree with it, you’re a denier who must be funded by Big Oil and/or the Koch Brothers!

  8. You mean it’s not going to get warmer? Now I have to buy all new winter clothes. Damn.

  9. Good, whatever. Do we get to continue our radical experiment to change the chemical makeup of the atmopshere for unprecedented profit for ourselves, and are you guys gonna keep being the unpaid crusaders for our agenda?

    1. It’s not a radical experiment to alter the chemical composition of the atmosphere. What’s radical is using the SUN for ENERGY. THAT’s CRAZYTALK.

      1. Herp a derp!

      2. Ok, whatever. Do we continue believing that humans should die or just succumb to reality?

      3. We already do use the sun for energy. We always have. The battery the energy is stored in is called Oil.

        1. …and coal…and water (hydroelectric). Supernovae have provided us with nuclear power.

        2. We already do use the sun for energy. We always have. The battery the energy is stored in is called Oil.


          If oil comes from a photosynthetic biological process then why does lifeless Titan have hydrocarbons?

          1. Devils advocate:
            Because HCs can arise for different causes under different conditions?

          2. Who says it’s lifeless?

          3. A lack of free oxygen leaves both hydrogen and carbon around to play with each other out yonder in the celestial sticks. Because usually, hydrogen like carbon are just panty-losing whores for oxygen. Free oxygen is really, really strange in the universe, it always shacks up with something. Usually hydrogen and sometimes carbon.

            Otherwise, you have to bust the oxygen off the carbon and direct it to the hydrogen, which is energy intensive via photosynthesis. And then the other investment in energy comes from the earth itself, when you put that chemistry under pressure and heat for a couple eons and cook off all the volatiles and bake those long chains in peace. Its more than just the Sun. That’s why you see long-chainers like kerosene and gasoline on Earth and only simple-simple compounds (methane, ethylene) for the most part out on Titan et’ al.

    2. Your agenda? I see a lot of people driving cars and using electricity and petrochemicals of all kinds. There seems to be pretty broad and enthusiastic participation in this experiment.

      1. Re: Zeb,

        For the Eco-wackos, humans are simply stupid and tools of the corporations, which are populated (seemingly) by something not human, just like the Eco-wackos themselves who presume to know better.

      2. Exxon is only supplying the energy. The purchasers are the ones doing all the actual evil converting of the energy.

      3. But polar bears eat fish.

        It’s just like in Jurassic Park when the tyrannosaurus rex changed into the opposite sex and mated with itself.

        You can try to drown nature but it just won’t stay dead. It just comes back every halloween and tries to murder it’s sister.

        1. entropy|11.29.11 @ 11:02PM|#
          “But polar bears eat fish.”

          Also Harp Seals. And the Harp Seals are probably pleased (if) the population of Polar Bears decreases.
          Don’t they have a place at the table?

          1. They do until they run into me.

    3. [sarcasm] Yes Exxon. The oil industry is designed to melt the ice caps. Heating homes, powering the electric grid, and transporting people is just a tolerable side effect of our quest to watch polar bears starve.[/sarcasm] :))

    4. Exxon|11.29.11 @ 5:29PM|#
      “…our radical experiment to change the chemical makeup of the atmopshere for unprecedented profit for ourselves,…”

      How much lying innuendo can a brain-dead jam into one sentence?
      Pretty sure this beats one of shithead’s posts,

      1. Shithead? You’re going to have to be far more specific.

        1. Not for me. Tony = Shithead. That’s all.

    5. unprecedented profit for ourselves


      You get penny or two for each gallon sold while we get 50% of the sales price and don’t have to do jack shit for it.

    6. If by “unprecedented profit” you mean a lower profit margin than Google, Apple, Microsoft and a whole bunch of other corporations make, then yeah.

    7. Exxon supports a carbon tax.Exxon CEO Tillerson

      so does Shell and BP and Pelosi and Gingrich and George fuciking Bush.

      The only reason we don’t have a global carbon tax is because the whole idea is so stupid that even the american sheeple are not yet quite dumb enough to support it.

  10. Dominika is what can only be described as a great girl – accomplished, sexy and with a stunning body. She is half Italian and speaks Italian perfectly.

    The mother of a 5 year old son, Dominika was on the national team for her country in swimming and gymnastic. Despite her tiny frame she has a strong and very flexible physique. She just oozes sensuality and also tells us that she loves to hang out on nude beaches!

    Dominika started modeling as little as 3 months ago as previously her ex-boyfriend stopped her from doing any kind of modeling.

    Small but perfectly formed, this newly born model is a natural in front of the camera!

  11. At the United Nations’ Cancun climate change meeting last year, climate negotiators set a goal of avoiding an increase of more than 2?C (3.6?F) above pre-industrial temperatures.

    “Negotiators”? On whose behalf???


    1. Hey! They’re ‘negotiating’ about who gets to stick a hand in you pocket!
      It’s not easy figuring out who gets to steal the green!

      1. Re: Sevo,

        The “Two wolves and a sheep voting on what to have for supper” metaphor being appropriate at this time.

        1. See? Now you know what that ‘negotiation’ is about.

    2. Since they’ve already technically succeeded, does that mean they’re going to cancel their Qatar vacation next year?

  12. If their work ultimately checks out that would mean that while the world will get warmer, it will likely not become catastrophically hot. In other words, the sky would be falling less.


  13. Well I for one see no issue with the sky falling. The only reason we are alive today is because Earths gravity manages to keep the sky nice and close to the surface.

    1. Actually, the Earth’s gravity would keep a much thicker atmosphere like Venus. Were it not for our oversized moon, we might not be here.

  14. Doctor: Dude, we think there might be something wrong with you.

    Dude: What is it doc, am I dying?

    Doctor: Well, maybe, or it could just be bad gas. We ran all sorts of tests and were not even sure our equipment is calibrated properly and we really don’t know a whole lot about some of your major organs, but yes, we think there is something very wrong with you.

    Dude: What should I do Doc?

    Doctor: Well dude, one thing that may help is to remove several of your major organs from your abdomen and replace them with cybernetic parts.

    Dude: Sounds expensive.

    Doctor: You bet it is, nothing like this has ever been done before and the cybernetic parts are untested.

    Dude: But will it work?

    Doctor: Well you see Dude, what we believe you have is an abdominal cloud, it’s this cloud of stuff running throughout your abdomen and it could cause some discomfort and serious gas. If we remove enough of your organs, the abdominal cloud won’t have anything to irritate.

    Dude: Could I just get some pain killers and maybe some Bean-o?

    Doctor: We’ll then we won’t get to try out our new procedure.

  15. Comrades! You do not imagine, I hope, that we pigs are doing this in a spirit of selfishness and privilege? Many of us actually dislike milk and apples. I dislike them myself. Our sole object in taking these things is to preserve our health. Milk and apples (this has been proved by Science, comrades) contain substances absolutely necessary to the well-being of a pig. We pigs are brainworkers. The whole management and organisation of this farm depend on us. Day and night we are watching over your welfare. It is for YOUR sake that we drink that milk and eat those apples. Do you know what would happen if we pigs failed in our duty?

    1. manbearpigs. Get it right.

  16. Keep pulling….you may see daylight yet! LOL

  17. “A new climate study suggests global warming may not be as dire as predicted.”

    No shit.
    A new study, huh?

    Thank god, because any empirical knowledge of classical political fearmongering certainly didn’t make me doubt all the screaming about armageddon if we didn’t allow the state to grow even more intrusive.

    1. +a lot, UJ.

  18. A colder Last Glacial Maximum implies higher climate sensitivities due to lower levels of atmospheric carbon dioxide.

    Well, no, a colder Last Glacial Maximum implies that when various things affecting the climate are completely different at some point in the last 120,000 or so years, the climate will be different.

    Saying that the only thing that has changed between then and now is carbon dioxide levels, and everything else has stayed the same, is just crazy talk.

    And I thought just last year the best scientific guess was that things were WARMER during the Last Interglacial Period, which is what is most directly comparable to now. If CO2 was lower then, why were temperature warmer if CO2 is the only thing that matters?

  19. Well, OK I never thought about it liek that.

  20. This articles helps me more.Thanks for your sharing,I will pay more attentions to your blog.Looking forward to your better and better articles.See you next time.

    1. How many attentions do you have to pay? I’m interested in earning some.

  21. Did the Holocaust happen less?

    1. Nobody cares about your retarded strawman.

    2. I don’t even know what this comment is supposed to mean. Spoof perhaps? I just can’t tell anymore.

    3. No, Tony, it didn’t. But, it’s nice to see you have no moral or ethical qualms about comparing the worst atrocity in the last century to a supported disagreement about scientific fact. Because all good science is based on smears and innuendo.

    4. “Did the Holocaust happen less?”

      Shithead, that is sleazy even by your despicable standards.

      1. The Holocaust = man-made.

        That’s the key, Tony.

  22. This is the beginning of the official Great Face-Saving Walkback.

    1. Exactly. In a few decades, when only sickly geezers are literate, the walkback will end as the warmenists start telling everyone that it was the actions of the IPCC that saved the planet

  23. Without the active support of newly industrializing countries, CO2 is absolutely beyond our control. They are not going to give up the good life that they are steadily gaining by burning fossil fuel Even if they did,
    and we did also, the change would hardly dent whatever is going to happen anyway.

    This subject is just about dead.

  24. 6 degrees C is not 13 degrees F, it’s 10.8 degrees F.

    1. jeeeezuz. 6 Degrees Celsius is 42.8 degrees on the F scale. Keep you head while others around you are losing their’s.

      1. You misunderstand. I know that 6 degrees C is 42.8 degrees on the standard American thermometer when you start at 32 degrees (0 degrees on the C scale). But 6 degrees C by itself is EQUAL to 10.8 degrees on the F scale. Get it?

        Bailey above says “6?C (13?F)” which is wrong.

  25. If Schmittner is right, (doubtful according to Real Climate), I don’t understand why Bailey thinks that adding a mere 11 years before we hit the wall is a big deal.

    What’s the plan, party until you drop?

  26. How long until the Reason editors figure out that Bailey has missed one of the biggest scams in history? The promoters of AGW have been found to cherry pick data to support predetermined conclusions, to prevent peer reviewed papers that disagree with their conclusions to be considered during the IPCC ARs, to manipulate and hide inconvenient data, to have used inappropriate methods that show no crisis when corrected, and admit that there is no adequate way to measure the global anomaly trend or calculate sensitivity from the current data. When will Mr. Bailey begin to see that the revelations are important and that they do matter?

    I don’t know about other readers but it seems to me that a magazine that shows a prudent and healthy distrust of official pronouncements by government agencies or special interest groups from all sides of the spectrum seems to be very naive when it comes to people who argue that they can determine temperatures within 0.1C in 2050.

  27. Thank you thank you thank you, Reason, for a REASONABLE article on global warming. Both sides of this debate have been full of hot air, with Gore and Limbaugh acting as poster boys for two extreme positions.
    I’m not worried about global warming myself, because it stands to reason that as the ice caps melt, they’ll drip lots of ice water onto the sun when it goes beneath the earth every night, thereby cooling the earth about as much as the earth is being warmed.

  28. Did anyone actually bother to read the paper? It concludes as follows –

    ” Our uncertainty analysis is not complete and does not explicitly consider uncertainties in radiative forcing due to ice sheet extent or different vegetation distributions. Our limited model ensemble does not scan the full parameter range, neglecting, for example, possible variations in shortwave radiation due to clouds. Non-linear cloud feedbacks in different complex models make the relation between LGM and 2?CO2 derived climate sensitivity more ambiguous than apparent in our simplified model ensemble (27). More work, in which these and other uncertainties are considered, will be required for a more complete assessment.”

    The most we can say is the increase of CO2 won’t result in as much warming as we thought, as soon as we thought. This really doesn’t change the fundamental point of the science at all.

  29. Quote from one of the lead scientists:
    “Science is an iterative process. Others have to check our work. We have to continue checking our work, too.”
    This is the basis of the scientific method. This is what has been missing from prior work from sources like Michael Mann and Phil Jones. If ever someone says “the science is settled” that person does not understand the scientific method. Science is rarely ever “settled”. Recent case in point: Relativity, both special and general. Relativity is under attack as a direct result of research in Quantum Physics. These two branchs of physics HATE one another and lead to frequent contradictions, poor Einstein. I agree science can appear ugly at times but the scientific method must be honored. The climate scientists forgot that one tiny detail.

  30. Ooooooooooooooooooooo, Al Gore is spinning like a music-box dancer!

  31. The climate scientists forgot that one tiny detail.

    They did? Could you quote something from a journal article that you disagree with from them, and show how the Schmittner paper (or any other paper) conflicts with their statements?

  32. The fact is that the earths atmospheric heat signature does not demonstrate a temperature profile consistant with a greenhouse warming effect. This is admitted by the East Anglia climatologists in the latest email release. If warming is not due to a greenhouse effect even the minimal, theortical effect of increased CO2 mentioned in this article is not happening. It’s time science moved on to look for more reasonable causes of inter glacial warming periods.

  33. this article is a little bit of interest, make me like it.

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