The Thought Experiment That First Made Me A Climate Skeptic

Please check out my Forbes post today.  Here is how it begins:

Last night, the accumulated years of being called an evil-Koch-funded-anti-science-tobacco-lawyer-Holocaust-Denier finally caught up with me.  I wrote something like 3000 words of indignation about climate alarmists corrupting the very definition of science by declaring their work “settled”, answering difficult scientific questions with the equivalent of voting, and telling everyone the way to be pro-science is to listen to self-designated authorities and shut up.  I looked at the draft this morning and while I agreed with everything written, I decided not to publish a whiny ode of victimization.  There are plenty of those floating around already.

And then, out of the blue, I received an email from a stranger.  Last year I had helped to sponsor a proposal to legalize gay marriage in Arizona.  I was doing some outreach to folks in the libertarian community who had no problem with gay marriage (after all, they are libertarians) but were concerned that marriage licensing should not be a government activity at all and were therefore lukewarm about our proposition.  I suppose I could have called them bigots, or homophobic, or in the pay of Big Hetero — but instead I gathered and presented data on the number of different laws, such as inheritance, where rights and privileges were tied to marriage.  I argued that the government was already deeply involved with marriage, and fairness therefore demanded that more people have access to these rights and privileges.  Just yesterday I had a reader send me an email that said, simply, “you changed my mind on gay marriage.”  It made my day.  If only climate discussion could work this way.

So I decided the right way to drive change in the climate debate is not to rant about it but instead to continue to model what I consider good behavior — fact-based discussion and a recognition that reasonable people can disagree without that disagreement implying one or the other has evil intentions or is mean-spirited.

This analysis was originally published about 8 years ago, and there is no longer an online version.  So for fun, I thought I would reproduce my original thought experiment on climate models that led me to the climate dark side.

I have been flattered over time that folks like Matt Ridley have picked up on bits and pieces of this analysis.  See it all here.


  1. Mercury:

    Well done. Unblinding them with science.

    assumption that has always peeved me is that all this is happening against a
    background of permanent climate stasis. Granted massive, “natural” climate
    shifts may or may not happen/be happening on a scale that we or our great^10 grandchildren need to be concerned with. But things like ice ages, whether
    caused by Milankovitch cycles or something else, are real and Natural doesn’t
    always = Good.

    You can’t prove
    this one either of course and I wouldn't want to act on this assumption but it is at least possible that massive APGW might be the
    only thing that could stand between now and (the return of) 100 feet of ice on 5th Avenue.
    However the “debate” isn’t about global warming anymore it’s about any and all climate
    change and it’s supposed to be understood that all future climate change will be the direct
    result of anthropogenic forces. Ugh.

  2. Zachriel:

    You seem to be conflating equilibrium sensitivity with the transient sensitivity. The latter is the direct effect. The former includes parts of the Earth system, such as glaciers, ice caps, permafrost, and the deep ocean, that require a long time to reach equilibrium. The transient sensitivity is estimated to be about 1-2.5°C. Much of the anthropogenic carbon is rather recent, so there hasn't been sufficient time for the system adjust.

  3. Michael Goad:

    Thanks for this. Frustrated with the continuing blather of warmists trying to lay the cause of the pause on something other than natural variation -- I think the most recent is volcanoes -- I often find myself starting to write something on climate change. I try to limit how often I do climate related posts. Otherwise, I'd just get obsessed with the topic... again.

  4. FelineCannonball:

    --Paleoclimate-based sensitivities are based on equilibrium conditions -- where the oceans, plant biomes, glaciers, and sea ice adjust slowly with changes in CO2. These sensitivities are going to be dependent on starting conditions and are not infinite (ice albedo feedbacks and soil /sediment CO2 feedbacks for instance don't keep acting after ice fields disappear and the carbon is mineralized). You can figure this full delayed feedback process plays out on a 10,000 year + timescale.

    --Technically Holocene records can't rule out natural variation larger than current warming. There is age and sampling imprecision that would dampen the apparent magnitude of very short global warm periods. It would be more accurate to say that we can't observe such short warm periods in the past rather than say that they did not exist.

    --GCMs are crude at this point. Modelers aren't going to be able to accurately model decadal scale global temperature changes using models that don't incorporate decadal scale ocean-atmosphere processes. Short term heat exchange, El Nino oscillation effects, etc. are subjects of active research and are by no means "settled" science. As is water vapor feedbacks, aerosols, detailed atmospheric structure, etc. It's pretty important to look at the variability in current model outputs with respect to these parameters. It's also important to look at what a model is attempting to model and the scale at which it's results are expected to be useful.

    -- As for the plots based on reanalysis and y-axis shifts, I'd suggest trying to get them published in peer review. Even if you don't get it through the process, you might get some useful feedback on why exactly climate scientists think you're wrong.

  5. mesocyclone:

    Too bad you don't use your "existing statutes" logic on immigration, since the same logic shows why free immigration is a bad idea.

  6. obloodyhell:

    Randall Munroe comments on AGW,,,


  7. Canvasback:

    So if conditions causing transient sensitivity fluctuate a lot , or just have a minimal trend, it sounds like the equilibrium could take a couple centuries to vary 1'C.

  8. Zachriel:

    Canvasback: So if conditions causing transient sensitivity fluctuate a lot , or just have a minimal trend, it sounds like the equilibrium could take a couple centuries to vary 1'C.

    If conditions fluctuate, then there could be a flywheel effect. The oceans, in particular, have a very large heat capacity. However, that it not what is projected to occur. The Earth surface system is expected to continue to warm.

  9. Gil G:

    What pause? The only "evidence" for a pause is from deniers.

  10. Gil G:

    A simpler thought experiment would be that of appealing to Justin Bieber to think of his children and grandchildren for his wayward behaviour. If he counters "I don't have children let alone grandchildren" then the reply is "well not just yet but chances are you will in time and don't you think it's fair that you act responsibly so when you do become a father you'll be both healthy and wealthy?" So:
    * Does he have a responsibility to the unwritten future and the children he will (possibly) have?
    * Does he have no responsibility whatsoever and if he does have children and he's stone broke because he pissed away his wealth via youthful exuberance then tough luck to his descendants? So they get angry at they at how they would grown up rich if Justin was a responsible person but they can't act as though they have a right to a responsible ancestor.
    Hence: do we have a responsibility to our unborn descendants? Do they have a right to us being responsible now? Or are we free to live the way we want and they pick up the pieces? For the Libertarian it's quite clear: even if the future climate is worse than the present then tough luck we're free to act as we like now and not be constrained by a hypothetical future.

  11. Gil G:

    So warming continues that growing season around the world start shortening: that mean food prices go and population pressures. Supposed the world get warmer leading to spread of a tropical environment: that means increased spread of diseases especially from those spread by the mosquito

  12. Douglas2:

    I can't tell if you are being sarcastic, or just have missed the latest special issue of Nature Climate change which is devoted to explaining and contextualizing the "pause":

  13. Canvasback:

    Well, we can always count on Gil G to come up with a simpler thought. He even manages to work his sensei, JB, into a discussion on climate feedback modeling. What Gil misses is that JB would be nowhere without his fans. As JB says, "It's all about the music." He's fooled some of the people all of the time. I think his grandkids would be proud of him.

  14. Thruppennybit:

    For the libertarian it is quite clear, but your reasoning is way off. It has only warmed for a 20 year period out of the last 60. The models have spectacularly failed to show any predictive ability (and as Warren shows, they don't hindcast too well either). So, thinking of Justin Bieber's offspring as well as my own, I really don't want their future constrained by unnecessary taxes and regulations and expensive and inefficient energy. They won't thank us for it.

  15. Gil G:

    I gave a hypothetical about JB because he's topical at the moment not because I give a particular rat's. Rather I simply supposed if the future climate were to be bad would that still means it's okay anyway as children get whatever they get and are not entitled to anything?

  16. Mercury:

    We do have a responsibility to our unborn descendants. Right now that responsibility is determining which is the greater risk: A) Doing little or nothing to try and reduce the risk of catastrophic, anthropogenic climate change or B) Doing whatever we can to try and reduce the risk of catastrophic anthropogenic climate change which would necessarily mean granting coercive state power and authority to micromanage our/their lives to an extent that would have many and far reaching negative consequences…even if it were for “the greater good”. On balance the evidence says that ‘A’ is worth the risk given the unpleasant and most likely permanent trade-offs associated with ‘B’.

    If (ours in particular) government had a better track record with this kind of situation that would be one thing…but they don’t. Just like the problem of “terrorism” will never be declared fixed there are many things that neither we nor our grandchildren will ever be able to do again as a result of that reality. Likewise the government would never declare the problem of “climate change” fixed, potential disaster would always be just around the corner and all the liberties that they are chomping at the bit to take away would never be returned.

  17. Mercury:

    Sure, that's a possibility (although I don't see how you can have an increase in tropical environment and a decrease in world crop yields at the same time) but it just doesn't seem terribly likely given the evidence.

    What's probably more likely is that we start to enter into another ice age as the Earth has done before with some regularity going back hundreds of thousands of years. Even though we're probably overdue for one another ice age might not begin again for another 1000 years or more. But it should be inevitable wouldn't you say? I mean, no reason to think those cycles have been suspended right?

    'Inevitable' is a higher level of probability than whatever chances you can ascribe to human induced climate catastrophe so, what are we doing about that? For all we know APGW could curtail or delay that somewhat which would probably be a good thing.

  18. Joshua Vanderberg:

    Um... The pause refers to the significant decrease in the rate of atmospheric warming observed over the past 15-20 years. This is an observed fact, which you appear to be denying.

    As for your links...

    Yes, the deep ocean release valve. Ocean heat is poorly measured and tiny measurement errors can lead to massive changes in heat content. Assuming the measurements are accurate, was this movement of heat to the deep oceans predicted by climate modeling? Nope - oops. So, *if* this ocean heating is occurring, we cannot currently accurately model it, or predict how it will affect atmospheric temperatures in the future. And we certainly didn't predict that it would cause the observed atmospheric temperature trend.

    My prediction: we'll have updated GCMs in a year or so which retroactively "predict" the pause, using one of the many hypothesis for the location of the missing heat - deep ocean heating sounds as good as any. They will accurately backcast the pause, and predict a return to rapid warming, say in 2020.

    Alas, I think reality will have other plans.

  19. Gil G:

    As said only deniers keep talking of a pause that no one else can find.

  20. Harry:


    Being a committed sophistic skeptic, I would appreciate your help.

    1) What is the number of parts per million that various parties, like the IPCC, the Sierra Club, or even the API argue that is man-made?

    2) So if man adds another 400 parts per million, has anyone reasoned when that will happen, and has that reasoning accounted for other natural processes, like more leafy plants?

    3) Let's assume, just for the sake of argument, that it is another 400 ppm. How many additional btu's is that, relative to the energy coming from the Sun, and the residual energy from the earth itself? What is the argument for CO2 being such an efficient heat trapper that it gains a sensitivity coefficient of 3 or whatever the modelers use?

    If there were convincing numbers on this, I would expect somebody who writes in English would have summarized these findings clearly to explain how something so minuscule can have such a powerful effect.

    4) Coyote, you did qualify your experiment by saying that the magnitude of the effect of CO2 was not part of your thought experiment, and I hope I have not misinterpreted any of your reasoning, which itself is deferential to what we do not know.

  21. Karl W. Braun:

    Here are the graphs of five major temperature datasets. It is quite evident that global temps really haven't gone anywhere this century. Mainstream climate scientists have begun to acknowledge this.

  22. Karl W. Braun:

    Disease carrying mosquitoes have historically been present in many temperate regions, including the United States and Europe. Indeed the very word "malaria" is Italian, meaning "bad air" which was once thought to be the cause of the illness. It was control through the use of pesticides and improvements in sanitation which led to the eradication of malaria and other such maladies from those areas.

  23. Joshua Vanderberg:

    Climate scientists are now publishing papers that attempt to explain the pause you claim they cannot find. That's a bit odd.

  24. Joshua Vanderberg:

    Why would growing seasons shorten? Where I live, growing seasons have actually increased slightly these last few decades. If warming continues on a more extreme path, large parts of Canada will become arable. And then there's the documented CO2 fertilization effect, which increases crop productivity as CO2's partial pressure increases.