August 25, 2004  ·  Richard Posner

At last, high-level Administration acknowledgment that global warming is real, and that human activity (mainly the burning of fossil fuels, principally oil, natural gas, and coal, and deforestation in Third World countries) is a principal cause because such activity emits carbon dioxide. (See also Times article.)

Greenhouse gases, such as carbon dioxide, in the atmosphere trap heat reflected from the earth and by doing so maintain a temperate climate. But since the Industrial Revolution and in particular since about 1970, economic and population growth has resulted in greatly increased emissions of carbon dioxide, resulting in greatly increased atmospheric concentrations of the gas (the effect of emissions is largely cumulative, because it takes a long time for carbon dioxide to be removed from the atmosphere, by absorption by the oceans), producing in turn higher global temperatures. As I explain in my forthcoming book Catastrophe: Risk and Response, because the global climate equilibrium is fragile, abrupt global warming is possible, though unlikely, in the near future. It would not be as abrupt as depicted in “The Day After Tomorrow,” but it might be abrupt enough to have catastrophic consequences within a decade or even less, consequences that might include a rise in ocean levels that would inundate most of the world’s coatal areas, where most of the largest cities and much of the world’s population are found.

The current global-warming problem is an artifact of technology (though not of the newest technology), which has not only made carbon the basis of most of our energy but has contributed to a great increase in the number and wealth of people, and hence to a great increase in the demand for energy. But technology may bail us out, either by developing feasible, economical substitutes for carbon-based energy sources, or, by advances in nanotechnology (molecular-scale engineering), creating carbon-dioxide devouring nanomachines to cleanse carbon dioxide out of the atmosphere. Unfortunately, as is so generally the case, technology has a downside; for example, concern has been expressed that the weaponization of nanotechnology could further destabilize the geopoliitcal system, and even that nanomachines might accidentally be created that were incredibly voracious self-replicators–superweeds that might devour all organic matter on the planet. See Nanotechnology.

  • Anonymous

    I rarely comment on this blog… but what on earth would be the power supply for driving “carbon-dioxide devouring nanomachines?”

    I mean, no matter what the scale, it still takes energy to break CO2 into it’s constituent parts. CO2 is, after all, the product of combustion; the only way to “fix” it is with some kind of photo-electric effect (whether biochemical or not.) And why would a nanotech solution be better than the more canonical CO2 fixing with plant life (or even some giant nuclear power plant?)

  • Fred Blasdel

    What is the common trait among the proof for these three theories?

    • Other Intelligent Life in the Universe
    • Stereotypical Post-Apocalyptic Nuclear Winter
    • Human-Caused Massive Climate Change

    All of the listed theories involve complex arbitrary equations in which most, if not all data is arbitrarily pulled from the ether. In english, the data (and the equations in to which the data is input) to back up all of these theories are essentially pulled out of someone’s ass.

    Also, all of these theories support wonderfully romantic notions that most people find so agreeable they suspend disbelief. Think about it:

    • “We are not alone in the universe”
    • “If we ever have a nuclear war, the whole world will get so fucked up, only Charlton Heston could lead us out of the frozen wilderness”
    • “With the way the world is industrializing to support our massive consumption, we will create massive climate change, yadda yadda, Charlton Heston, yadda yadda!”

    I just think it’s awfully egotistical of us as a species to assume that we can fuck up Gaia. We might be able to claim a role as an extra in influencing the course of worldly events, but the earth would change without us. Species would evolve or go extinct. Geological forces would continue to cause sea levels and ambient temperatures to rise and fall. Get over yourselves, we’re but puny homo sapiens in a larger context than we will ever know.

    The thing is, we really really, suck at predicting the future. In turn of the century New York City, people were trying to figure out what they would do about all the horse crap and other assorted tenement sewage in the streets. Within a few years, everyone was driving Model Ts and taking public transit. And someone even went and invented ass bags for horses for luddites willing to compromise a little.

    The unifying moral to this fable of scientific fallacy is that in the course of human progress, mistakes always appear to have been made through extrapolation of past data. However, the ultimate result of human progress is that innovation invalidates the shotcomings of past inventions.

    Even if, for arguments sake, we are causing some sort of global climate change, we are already fixing whatever it is we were doing wrong in the first place. Once China and India catch up with the proverbial Jonses, the world will pick a new cause to bitch and whine about. Change is inevitible, and would happen with or without our petty interference.

    Food for thought: The earth went through two rapid global climate changes (I think we’ve been calling `em “Ice Ages”) fairly recently in geological terms, without even so much as an Iron Age to help things along

  • Anonymous

    Posner are you on drugs? If you were making money via advertising, then I could see why you would cackle with scary blog posts (to get the attention of an audience to which you could sell to a sponsor). I think I will unsubscribe from this blog because your cackling is imposing ennui on those who subscribe. Lessig’s blog is now banished from my RSS feed.

  • Heidi

    Gee, Fred. For some reason, I thought that global warming differed from asserting that intelligent life existed for a couple of reasons:

    • We actually have data on carbon dioxide levels and mean global temperatures going over several millions of years, so that we know the two are correlated.
    • We actually understand how carbon dioxide could causes global warming (and the reverse).
    • The earth actually is warming.
    • We actually are releasing significant amounts of carbon dioxide into the atmosphere.

    And while we’re at it, this bizarre assertion on your part:

    • We actually have caused species to go extinct.

    Now, what you appear to be griping about is that we’re not very good at figuring out what the effect of our releasing carbon dioxide will be. And we aren’t–we don’t know all of the ways that the planet buffers carbon dioxide and heat (for instance, scientists lately found out that carbon dioxide was dissolving in the ocean, making it more acidic). You’re quite right that we might not have ocean levels rising as the ice caps melt. But just because we can’t actually predict the catastrophe doesn’t mean it won’t happen.

    Your mention of previous catastrophic climactic changes demonstrates that the earth’s current buffered equilibrium can be changed, if pushed enough. We’re pushing. Maybe we aren’t pushing enough, but maybe we are. I have a lot more respect for people who say, “gee, let’s plan for a possible future” or even “gee, I know there will be errors in my extrapolations, but let’s see if I can figure out what some of those possible futures might be” than the people who say “la la la, let’s stick my fingers in my ears and pretend, because gosh, it’s so arrogant to say that humans could change anything.”

    Yes, we suck at figuring out exactly what the future will be. But we’re also pretty good at figuring out what all the potential futures might be. We’re stuck in a complex landscape, where small variations in data or extrapolating mechanism might have a large variation in result. That’s okay, as long as we understand that we’re taking a probabalistic point of view.

    Duh, the earth will change without us. But it also changes with us. Arrogance is ignoring some probabilities.

  • realish

    Let’s see, what should we trust? Fred’s crusty folk wisdom, or the consensus of the worldwide scientific community, almost every major government on the planet (now, finally, including ours), large insurance companies, large oil and gas companies like BP and Shell, etc. etc.?

    I’m going with Fred’s crusty folk wisdom! Whew, everything is peachy. I was worried there for a while…

  • Karl

    When you start solving scientific equations with consensus, you end up with programs like eugenics. There’s no such thing as consensus science. Nanotechnology, however, is tons of fun, sadly it’s too often linked to the pariah of nuclear power for anyone to touch it.

    When I read this post, I was waiting for the comic twist, sadly it never came. Please, Judge Posner, don’t tell me you support the Kyoto protocol, a mechanism that would cripple more innovation than the CTEA could ever dream of.

    Everyone should read: Aliens Cause Global Warming

  • ravi srinivas

    In myy opinion global warming is also an issue about equity and ethics and it is small islands that are liklely to be the most affected although they have contributed almost nothing to even if technical solutions are found these questions may not be answered adequately.

  • Rob

    I think it’s stupid to say “well, the scientists can’t prove one way or the other that human-caused global warming is real, so let’s just keep polluting as much as ever until they do.” That’s the equivalent of the proverbial “waiting for the mushroom cloud” to indicate terrorist possession of nuclear weapons. We’ll know we’ve caused global warming if we make the planet uninhabitable? Er, I think I’d like to avoid going that route if it’s even a remote possibility, thanks.

  • realish

    When you start solving scientific equations with consensus, you end up with programs like eugenics.

    That’s the dumbest thing I’ve ever heard. You solve scientific problems with science, and that’s what climate scientists have done. There are some industry-funded cranks who differ, so who are you going to trust? My guess is, on issues where you do not have an ideological axe to grind, you trust the scientific consensus, because the scientific consensus typically (not always, but typically) reflects the best available science.

    I’ll tell you what would spur innovation: the removal of the vast government subsidies going to the oil and gas industries. End those, end the ability of those industries to externalize costs (costs taken up by the taxpayer), and I guarantee you you’ll see a burst of innovation around renewable energy.

    Opponents of science — that is, of the theory that humans are contributing in large part to massive, rapid climate change — like to pretend like the effort to meliorate global warming will mean massive government intrusion, disturbing our pristine free market. But that’s a joke. If we had a geniunely free market, it would have corrected away from energy sources that cause not only massive pollution, with its attendant health problems and clean-up costs, but climate change that is set to drive their insurance costs through the roof. In a free market, we would be well on the way to greater energy efficiency and cleaner sources of energy. We don’t have a free market, we have a market heavily weighted towards industries with lots of friends in government — and it is, quite literally, killing us.

  • Sigivald

    Realish: There is no scientific “consensus” that human action is a significant force behind global climate change. There is, on the other hand, some arugment both ways, lots of argument between sides, and a repeated desire by the pro-human-action side to claim (or, as often, manufacture) “consensus”.

    In terms of the data and the models, analysed and compared with counter-examples and counter-argument, the question is very much open, no matter how many companies or governments got convinced by people talking long and loud. (Especially since companies can gain brownie points and often government money by going “green” in the facade and talking big about global climate change, often without any significant sacrifices on their end. Ditto governments, in many cases.)

    Any discussion of CO2 output, for instance, ought to mention the comparatively recent revelations about increased solar output, which appear to explain global warming quite adequately without any significant input from Humanity, let alone any that would require reworking the world economy. The case is not open and shut, in other words, and we ought not pretend it is, if we’re interested in science, rather than religion.

  • Realish

    No, Sigivald, what’s manufactured is the impression that this is an open question with no consensus scientific position.

    Opponents know exactly how to manufacture this impression. It is not an open question whether humankind evolved, either, but enough fog and faux-science from intelligent design theorists have left many with the impression that it is. It’s not an open question whether Clinton murdered Vince Foster, but enough hand-waving … etc. etc. It’s easy to fool the public into thinking there’s no settled opinion on matters, because there will always be someone out there to produce “evidence” or a “study” that you can cite to show that there are “lots of arguments” — and the evidence or study is inevitably rebutted, piece by piece, on page F23 of the paper, where nobody sees it.

    Yes, I’m familiar with the “revelations” about solar output. I’m familiar with the recent “revelations” that economic factors influence the temperature record, and recent “revelations” that the urban island warming effect distorted temperature measurements, and recent “revelations” about temperature stability in the troposphere, and on and on. To say there is scientific consensus is not to say that every single scientist agrees — there are lots of scientists out there, and you can always dig this stuff up. (If you care to see them debunked, check out Tim Lambert’s site — he knocks them down one by one and offers plenty of sources for you to follow up.)

    But the point is, despite these splashy revelations, each of which is credulously reported by the media and then demolished by other scientists, there is, in fact, among the climate science community, a consensus that humans are contributing to climate change. I don’t know how or why exactly this became a political issue, but understand that when you fall for and repeat the BS fed you by climate science skeptics, you are playing politics, not science.

  • Anonymous


    Doesn’t the McCarthyism which these so called legitimate scientists are stooping to smell somewhat rotten? Why is the fact that dirty SUV driving humans are destroying the earth the one fact you’ll accept unequivocally, no matter what?

    Einstein was a skeptic, Galileo was a Skeptic…I could go on for pages. Skeptic wasn’t a bad word in science until Environmentalism became a cult. Cult isn’t a difficult moniker to pass here, because it’s obvious how blind environmentalist zealots have become and how fervent they put down any criticism.

  • Jeff Licquia

    Opponents of science � that is, of the theory that humans are contributing in large part to massive, rapid climate change…

    Is this a self-parody?

  • Realish

    Yes, yes, I know how this argument always goes. You accuse the guy who’s defending the science of “zealotry” (and/or “religion”) and try to place the industry-funded hacks who produce these studies in the company of Einstein and Galileo. It is to weep.

    I’ve had exactly parallel arguments about evolution. Am I “zealous” about defending the theory of evolution? Yes. But my zealotry issues from, rather than precedes, the scientific evidence — thus setting it apart from religious zealotry. You can cast the brave intelligent design skeptics as latter-day Galileos too, if you want. But sometimes — nay, usually — rejecting the scientific consensus makes you a crank, not a hero.

    Climate change is not as settled a scientific question as evolution, but it’s a hell of a lot closer than the public’s been led to believe. Mainstream scientific organizations have done a poor job of communicating about this and they’ve let the airwaves be hogged by media-hungry skeptics and the politicians and industries whose interests they ultimately serve. I guess faux-outlaw skepticism is more sexy than stuff like this letter to Congress, signed by 1000 scientists, which begins as follows:

    Two years have elapsed since the publication of the most recent reports by the Intergovernmental Panel on Climate Change (IPCC) and the National Research Council (NRC) on the state of the science of climate change and its impacts on the United States and the rest of the world. As scientists engaged in research on these subjects, we are writing to confirm that the main findings of these documents continue to represent the consensus opinion of the scientific community. Indeed, these findings have been reinforced rather than weakened by research reported since the documents were released.

  • Joe S.

    Nanotechnology? Uh, isn’t that a fancy word for “chemistry”? Is anybody on this thread old enough to remember colloids?

  • Brett Morgan

    Nano technology carbon dioxide munching machines? Wha? Try plants. They have been binding carbon dioxide and water for millenia and using nothing but sunlight. No need to wait for high tech answers on this one…

  • Heidi

    All of this trash talk about who’s a zealot and who’s a skeptic is making my head hurt. The difference between zealotry and adherence to something you believe to be true is what evidence you have examined and how willing you are to examine your beliefs in light of new evidence. There is nothing wrong with having strong beliefs that are supported by evidence. To the person who has not examined the process of belief-formation, both the zealot and the believer appear indistinguishable. But it is the process that matters.

    In the words of Carl Sagan:

    Prejudice is making a judgment before you have looked at the facts.

    Postjudice is making a judgment afterwards.

    Prejudice is terrible, in the sense that you commit injustices and you make serious mistakes.

    Postjudice is not terrible. You can’t be perfect of course; you may make mistakes also.

    But it is permissible to make a judgment after you have examined the evidence. In some circles it is even encouraged.

  • Fred Blasdel

    Glad I sparked some debate.

    If we (the US) were to ratify the Kyoto Protocol, it would cost billions, expedite the offshoring of industrialization, and do next to nothing to quell human greenhouse gas production. China and India, on the other hand, could maybe do something. But they won’t, and they probably never will. Besides, all our production is a pittance compared with natural geological processes like volcanic activity.

    Yes, human influence has already taken it’s toll on the more maladapted of nature’s flora and fauna, by way of Natural Selection. Guess what? We’re a force of nature too.

    The very similar idea of nuclear winter, once widely accepted in all circles (consensus even!), once regularly made into post-apocolyptic “Day after Tomorrow flicks, is now quietly “forgotten.” Just like eugenics and other so-called scientific disciplines where consensus trumped reason.

  • Mojo

    I guess some of the reactionary conservatives didn’t get the word. “Global Warming is a Myth” is no longer on the list of talking points. Wake up! An administration led by two oil-company executives has even finally been convinced!
    Many of the arguments against Global Warming amuse me no end.
    - “There are natural forces affecting climate change.” Yes, and human contributions are added to that. If you’re standing up to your chin in sewage, “just a couple of inches” added to it suddenly seems really significant. If we’re actually in a period of increased solar gain, do we really want to magnify the effect?
    - “The earth has mechanisms for dealing with CO2.” Yes, and like any such mechanism, they can be overloaded. For example, the oceans can only hold so much CO2; and that limit decreases as the temperature rises.
    - “In turn of the century New York City, people were trying to figure out what they would do about all the horse crap”. The crap didn’t disappear by itself; people changed how they acted and that corrected that problem.

  • Palooka

    Judge Posner,

    I respect you greatly, but such categorical statements are hardly the hallmark of a self-proclaimed skeptic. Geologists admit that climate changes occur often aburptly without human industy. And, of course, there is no question if climates change greatly, even in the absence of mankind, correct? Therefore, quantifying how much global warming is attributable to global warming is, to say the least, a herculean task. I have a great respect for science, but in the spirit of science, I am also a skeptic. There is simply no way to quantify the portion of global warming due to man.

    All of this groupthink here reminds me of an article I read recently, please check it out.


  • Fred Blasdel

    The thing with the horse shit:

    The shit problem was not fixed by people saying things like “We should build a shit railroad going out of the city, like the one we already have taking meat in and out of the meatpacking district (the High Line)” or “We should build these newfangled auto-mobiles, they’ll solve the problem (and create new ones)”.

    No, the problem was fixed because people said to themselves “Wow! These newfangled auto-mobiles are cool, and I don’t have to feed and stable it.” The lack of accociated poop was but a pleasant side-effect.

    Just as dependence on polluting technologies will only decrease when revoulutionary, bad-ass, more profitable technologies come along that just so happen to be less-polluting. New tech will come along, it always does, it’s just never as anticipated.

    Where’s my goddamn flying car?!

  • realish

    Ah, add to Fred’s crusty folk wisdom the old chestnut that technology will save us.

    Hey, you know people who believe that aliens have visited us and abducted folks? They’re brave skeptics denying the scientific consensus too! So are folks who believe in crop circles, ESP, and miracles. Do you count yourself among those skeptics too, Fred? And if not, why not? How do you distinguish between the consensus on relativity, the consensus on evolution, and the consensus on climate change? Or do you dismiss all of them, you maverick you?

    And by the way, the alleged “consensus” on eugenics was a (heinous) moral consensus on a moral issue. The scientific issues around genetics, etc., are fairly well-established. The moral issues regarding how such knowledge should be used are a whole different ball of wax, and are totally irrelevant to the argument you seem to be trying to make.

  • Realish

    All right, one last thing before I retire from this depressingly scripted debate.

    The reason I get upset — heck, even “zealous” — when arguing with the skepticism of folks like Fred and Palooka is that climate change is not only happening, it’s having concrete effects. Glaciers are melting, sea levels are rising, ocean currents are changing course, and weather patterns are shifting. Heat waves, droughts, and floods are killing people. It’s not an academic question: Right now, thousands of deaths are resulting from climate change every year. Fred casually dismisses these lives as “the more maladapted of nature�s flora and fauna.” This attitude toward the very real suffering of other people is risible.

    Eventually, the agricultural, economic, and political disruptions brought about by severe weather are going to impact the U.S., and it will be roused from its complacent slumber, long after many of the intervening deaths could have been prevented.

  • ErikH

    What you see here was discussed in a brilliant article which sadly I don’t recall the title of. Here’s the gist of it:

    The same people who are liberal and believe (based on experience) that global warming is real and evolution is correct are generally those who are 1) willing to change their opinion given sufficient evidence.

    Conversely, those on the ultraconservative side–no global warming, no evolution, etc etc (think abortion, gun control, etc) are generally unwilling to change their belief. An example is my highly religious friend, who in response to my question “you mean that even if God sent an angel to you and told you to stop following the Bible and use a magic 8-ball you wouldn’t change?” said “No. if he did that he wouldn’t be God”.

    Liberals can–in some cases–be convinced to adopt a conservative view. This makes sense, as liberals prode themselves on their willingness to adopt new viewpoints based on data. I’m an example; I’ve read papers that had me decided global warming was too huge a trend to be affected by human intervention, though I have since read other material which has changed my mind.

    Conservatives, on the other hand, can almost never be convinced to adopt a liberal view, because both their views and their thought processes are conservative.

    This means that liberals can become conservative relatively easily, by the advent of new data supporting a conservative view. Conversely, conservatives will rarely adopt liberal views, even when their own personal beliefs conflict with reality–because it’s the beliefs that matter, not reality.

    And THAT, my friends, is why there are so many more conservatives who deny reality than have any right to exist.

    Judge Posner, like my response? Want to hire me as your clerk? :)

  • Diane Bay


    Are there charts that show average temperatures worldwide increasing more than usual since 1970? Would you send me one?

    I don’t care if skeptics say the equations have a lot of unknown variables; if the temperatures worldwide are rising, then global warming is REAL.

    Diane Bay

  • Diane Bay


    Here’s an unbiased link.

    How could it be a “mistake” to, for example, stop stripping the Amazon of trees? Saplings are just not that expensive.

    Diane Bay

  • Mark

    Any discussion of CO2 output, for instance, ought to mention the comparatively recent revelations about increased solar output, which appear to explain global warming quite adequately without any significant input from Humanity

    I’m not sure what you mean, Sigivald. Perhaps you are referring to an article a few weeks back in Rupert Murdoch’s Daily Telegraph, which claimed, as you do, that solar variations are the cause of current global warming. They referenced the work of a physicist named Sami Solanki at the Max Planck Institute, and claimed that his research reached the conclusion I just outlined.

    However, when I actually tracked down Solanki’s published research, I found the exact opposite. A pair of recent papers by Solanki and Natalie Krivova found that while solar variation explains temperature trends through about 1970 very well, solar variation cannot account for the observed warming trend of the past 25 years.

    In other words, the Telegraph reported the exact opposite of the facts–no surprise, considering the publisher.

  • Anonymous

    Have we ever had another period in recorded history where the 2 poles were shrinking at such a rate. Sometimes you have to look for other clues.

    Oasis Wellness Network

  • JS

    ErikH: Your comment is correct if one defines conservatives as those who do not think flexibly, and liberals as those who do. But I do not think that definition would fit the real world very well. You started out by talking about “ultraconservatives” but then switched to talking about “conservatives,” and you seem to equate conservatives with religious fundamentalists. No doubt, there are many of those in the U.S. But I would suggest that there is also a number of conservatives who could also be called classical liberals, they think for themselves but simply do not believe, based on evidence, that big-government solutions work well. For example, many libertarians could be called conservatives, in that they are generally opposed to a big state, even though they are generally not religious fundamentalists. Thinking conservatives of this kind and other kinds, in my own experience, thoughtfully considered, have experiences different from yours, leading them to read the evidence differently, or leading them to see different evidence. We all contribute to public debate more effectively if we are open to the possibility that not everyone on the opposite side is unthinking. If we do view them as unthinking, we will not persuade them, and will even turn off some of the broad-minded people on our own side. Some on the other side are fools, of course. But not all.

  • Globalwarming

    There is very good information on this site. We all understand that it critical to understand what is going on. That is why we started the ?Global Warming Forum.? We must be willing to share ideas and talk about the climate changes that are taking place.

  • BB

    Where is all the strong evidence that global warming is caused by man? The only things that science agrees on is that people have released CO2 in the air, that CO2 is a minor greenhouse gas, and that theoretically CO2 will increase global mean temperatures. Global warming proponents say that we have thousands of years of data that shows a correlation between global temperature and CO2 concentrations, but the same data shows CO2 lagging behind global temperature by 800 years. If CO2 was causing global warming, can someone explain to me why the stratosphere is not warming. Even the computer models made by climate scientists show that the stratosphere should be warming faster than the earth’s surface.

    I’m not saying that global warming isn’t occuring or isn’t due to man; I just do not believe we have enough evidence either way to begin making policy changes on this issue. I don’t care about a consensus of scientists. The good thing about science is that you can look at the data yourself and come up with your own conclusions. Scientific consensus believed in a flat earth and global cooling.

    Personnally, I think environmentalists should be focusing more on toxins released into the air and water instead of chasing an idea that isn’t proven.

  • Hank Kingsley

    The arrogance and rigidity displayed by ErikH renders his entire post a laughable exercise in self-referencing irony. Somehow I suspect Judge Posner wouldn’t be impressed.

  • Aaron

    Global warming, if it actually exists, should be something we should take more seriously. The only problem is that it might not destroy the wolr, maybe it will lead to something else. I think of it as a cycle that will need to another ice age. It may put a little bit of land under water, but we can’t stop that, it’s a cycle the world could have gone through before we even existed.