Nordhaus on Climate Change Skeptics and Intellectual Debate

William Nordhaus has written a concise piece stating his views about climate change skeptics. He focuses on six questions.

They are:

• Is the planet in fact warming?

• Are human influences an important contributor to warming?

• Is carbon dioxide a pollutant?

• Are we seeing a regime of fear for skeptical climate scientists?

• Are the views of mainstream climate scientists driven primarily by the desire for financial gain?

• Is it true that more carbon dioxide and additional warming will be beneficial?

He doesn’t tackle the question of climate change adaptation but the skeptics haven’t even bothered to raise this issue.

Author: Matthew E. Kahn

Professor of Economics at UCLA.

40 thoughts on “Nordhaus on Climate Change Skeptics and Intellectual Debate”

  1. “What is the evidence on the performance of climate models? Do they predict the historical trend accurately?”

    Strictly speaking, one predicts the future, not the past. Granted, it is important that a model at least agree with, (Not “predict”) the past. But any model with enough arbitrary coefficients can do that much, while still being no good at actually predicting the future.

    That’s why predicting the outcome of experiments one does not already know the outcome of, and thus can not build into the model, is the gold standard of confirmation. Not “predicting the past”.

    What Nordhaus describes as “performing an experiment is nothing of the sort, the term “experiment” is only a metaphor when it comes to confirming that a model agrees with the data that went into constructing it. And not a very good metaphor, at that.

    None of the models, or so I understand, predicted the last decade’s stall in warming. They may have been tweaked after the fact to agree with it, but that’s not prediction.

    I think it would be fair to say that, when the models can actually predict climate before it happens, they’ll have passed an important test. Let’s not pretend they’ve passed it already.

    1. So, Brett, do you follow these precepts when it comes to economic models?
      Let’s take, for example, the theory that “lowering tax rates for the rich will raise overall revenues”. Do you believe this? Based on what?
      How about the theory that “lowering tax rates for the rich will result in trickle-down wealth”?
      How about the theory that “higher salaries for CEOs make them better managers”?

      Or, let’s take a slightly different subject. What about the theory that “without skin in the game, people will overuse medical services”? What about the theory that “medical professionals, in the system of privatized American medicine, would never use their privileged position to route patients to facilities they own, and suggest unnecessary tests and procedures”? How about theory that “what is driving American healthcare costs up is malpractice lawsuits”?

      Seems to me you are happy to espouse a hell of a lot of theories that have no validation whatsoever. They aren’t based on what happened in the past, they aren’t based on what has happened in other countries, and when they have been tried they have resulted in very different outcomes from what has been claimed for them.

    2. This may shock you, Brett, but predictions of continued global warming have been just that: predictions. Many were, in fact, not devised today, but decades ago. You may have even heard of them before today. Can you guess what has happened to the global average temperature in the interim? No? Well, perhaps you could Google that.

      1. = = =
        calling all toasters @ 10:14 “Can you guess what has happened to the global average temperature in the interim? No? Well, perhaps you could Google that.”
        = = =

        Actually, there’s an app for that, helpfully provided by NASA JPL.


    3. None of the models, or so I understand, predicted the last decade’s stall in warming.

      That’s because it never happened. Nine of the ten hottest years on record have occurred since 2000, and 2011 was the overall 9th-hottest year on record.

      But it’s a lie you’ve told before, and one you’ll tell again.

    4. Let me make sure I’ve got this right. Your claim, Bellmore, is that climate change scientists are unaware or are ignoring the issue of overfitting?

    5. Bretty wrote “None of the models, or so I understand, predicted the last decade’s stall in warming. They may have been tweaked after the fact to agree with it, but that’s not prediction.”

      Your understanding is incorrect. See the figure, which shows the range that models (with different iterations of potential random events, different initial conditions within the error bars of measurements, etc.) allow, predicting from 2000, as the grey shaded area. Taking the particular question of “what range of trends from 1998-2011 are allowed” in all the models, the range of temperature gains predicted is -0.07 to +0.49 degrees/decade; ie, 13 years is a short enough period that models did predict that random events can cause a net fall in temperature (which of course we did not see – there is still net warming.)

      The models also predict other quantities than temperature, and some of those quantities are less susceptible to random noise. For example, ocean heat content down to 2000m – see

      (all these are taken from the article )

      1. I wrote the above post – posting as “anonymous” was a pushing-the-wrong button mistake, and “Bretty” was a typo – no dis-respect intended. Apologies for both.

  2. Matt is too kind to point it out, but the global-warming denialists – the people Brett wants us to listen to instead of the climate scientists – have been quoting Nordhaus’s work as supporting their viewpoint. Nordhaus’s column, politely, calls them out for the liars they are.

    A final point concerns economic analysis. The sixteen scientists argue, citing my research, that economics does not support policies to slow climate change in the next half-century … I did the research and wrote the book on which they base their statement. The skeptics’ summary is based on poor analysis and on an incorrect reading of the results. The first problem is an elementary mistake in economic analysis … This leads to the second point, which is that the authors summarize my results incorrectly.

    Read the whole thing. When Nordhaus is done, there’s nothing left where the denialist position was but a little spot of grease.

  3. After that latest display of disingenuity, I am gonna do my level best never to read another word Brett Bellmore writes.

  4. Well, let’s give Brett the benefit of interpretation. I take his recommendation to be that we should make climate change predictions now, and then observe what happens for a few decades. If South Florida goes underwater, he will assuredly and with good humor agree that they were good predictions. It would be inexcusable to interfere with an important experiment like that by cutting back on GHG releases now (not to mention unkind to people who still have oil and coal to sell, and whose yachts are smaller than some of their golf buddies’ and have every right to upgrade). Anyone who thinks we should do anything about climate change now is just anti-science.

    1. Look, like it or not, that’s what “predict” means. “Pre” “Dict”; “Say” “Before”. If it’s already happened, you can’t predict it. That’s just what the word means, no hard feelings, doesn’t matter one bit if it’s inconvenient.

      Anybody capable of fitting a polynomial can create a model that predicts events after the fact. But that’s not “prediction”. And it doesn’t demonstrate understanding, just basic math skills.

      And, no, the models didn’t predict the 10 years so far stall, or else there wouldn’t have been any reason to deny it was happening, because it would have been confirmation, not a statistical fluke. Doubtless the models have now been modified to agree with what happened, and properly so, but they didn’t predict it.

      Words have meanings. You can’t predict what you already know has happened.

      1. Scientists do it all the time. Sometimes they call it postdict, or .
        Sure, one has to approach it with honesty, and care about overfitting. But it’s still a valid technique.

        Cosmologists do it when trying to account for the initial abundances of simple elements. Post-diction is the only tool they have, since we can’t restart the big bang. (think of the lawsuits!)

      2. Words have meanings, yes. I look forward to quoting you on that.

        Quibbling about definitions in order to not talk about the topic at handhas a long, distinguished history as well.

        I would be interested in Brett’s answers to the questions posed. Obviously, neither he nor I am a climate scientist. But he seems to have variant positions on the topic, and rather than bitching about word choice, actually saying something about why he at least seems to disagree with mainstream science might be in order.

        Here you go, teach the controversy.

      3. Here is a suggestion about how to view predictive models based on historic data.

        Pick a time frame in the past, say 1900 to 1980.
        Find the models (not spline fitting, etc) that do a decent job at predicting that time frame.
        Then apply those models to the subsequent time frame, and see which do the best.

        It’s still far from gospel, and can still suffer from over-fitting. But we peer at the future through dark glasses.

  5. Or we could just take a lesson from Will Rogers: “It’s easy to make money in stocks. Buy some stock, and if it goes up, sell. If it don’t go up, don’t buy it!”

  6. The debate about the global warming debate can be caricatured as choosing to believe either that:
    1) Global warming skeptics’ statements on talk radio are true or
    2) The academic community’s consensus has it right, so any frustration with that consensus is unreasonable (if not proof of gross ignorance)

    I would suggest a third possibility, that anthropogenic warming exists and is a serious problem, yet there is also poisonous group think occurring among the right-thinking side of this debate.

    Let me take Nordhaus’ graph as an example. He invites an eyeball analysis, and I have nothing more I can bring to the table. I have no training or background in climate science.

    Nordhaus discusses the figure as if it shows upward long run trend + volatility, but that is not at all what I see. I see that plus also trends that last 20-40 years. Yes, there is a clear long run upward trend and of course there is random year-to-year variation, but I also see a downward trend from 1880 – 1910, up from 1910 – 1940, flat from 1940 – 1980, up from 1980 – 2000 and then there is the much debated 2000-2010. My eyeballs aren’t good enough to judge whether that 2000-2010 period is flat or still upward but only appears flat because of random variation.

    Now maybe my eyeballs are wrong about those several-decade long trends. If so, then I’d at least want the climate community to say, “Yes, we acknowledge that it looks like there are 20-40 year trends, but that is just a trick of the eye; the human tendency to see patterns when they don’t exist.”

    But I’m skeptical that’s all there is. I suspect that some sort of spline model with data-determined break points in trends would beat a simple concave growth + noise model for this time series. That is, I suspect there is something else going on that creates multi-decade long trends, not just a CO2 driven long run upward trend + noise. Perhaps climate scientists even know what that is, something about El Nino (although that is more like a 7 year cycle) or eccentricity of earth’s orbit (although I thought that was a 21,000 or a 26,000 year period thing). But the climate community hasn’t managed to explain these 20-40 year long trends’ origin to people like me with a NY Times level knowledge of the issue.

    So the feel of the debate is that there is both an elephant in the room (the long run steady increase) and a gorilla (these 20-40 year trends). And the academics are crying foul because the skeptics are ignoring the elephant in the room, yet the academics aren’t acknowledging the gorilla.

    And it’s pretty obvious that if there is something that causes 20-40 year trends, not just C02 plus year to year variation, that does complicate the global warming story. Getting 10 straight years of ever higher temperatures is pretty convincing evidence of global warming if the whole story is trend + random yearly variation. Not so likely you’ll toss 10 heads in a row. But if the climate system has 20-40 year trends, then getting 10 straight years of increasing temperature would be more like tossing one head.

    Now, I want to be clear that to me the overall evidence of global warming is solid. I am not disputing the long run trend. But I am saying that the academic consensus breeds paranoid skepticism through its silence about things like this “gorilla”.

    And I don’t want to single out Nordhaus or that graph. It is almost a weekly occurrence that I see some statement (newspaper reporting level; I’m not reading the science literature) that someone appears to think is slam dunk proof of global warming that doesn’t hold up to common sense scrutiny of the sort academics are supposed to subject ideas to. A recent example was: over the last decade this or that song birds’ range has moved north by ~500 miles from northern Mississippi to Chicago. Yeah, but even if we believe the climate change models, the slope of the global temperature rise isn’t anywhere near large enough over just 10 year to approach the south-north temperature gradient over 500 miles. Why can’t that change in birds’ range be a response to other human interference in the ecosystem? After all, we’re still within the first 100-200 years after we eliminated all of the apex predators from the Continental US and more or less deforested the entire country east of the Mississippi and now the forests are growing back. Hardly seems like we should be in some sort of ecosystem equilibrium with all changes necessarily attributable to long term global warming.

    Obviously Nordhaus is right that skeptics are not being sent to slave labor camps, but that does not mean there is a social climate that welcomes moderation in statements about global warming. If I had written a letter to the editor raising the question I just did about the song bird range extension, I am confident I would have been given a cold shoulder at best by most of the people with whom I work and socialize. So I didn’t, and neither do others — except talk show radio hosts.

    And that leaves the tens of millions of people whose first instinct is to be skeptical of academics’ opinions on policy issues to see that there is an absence of self-criticism in the debate as they witness it. I — since I am an academic — just assume that the newspaper-level debate is unlike that which takes place in academic journals. I assume (with no direct observation) that scientists and the scientific method are doing their job and not reporting things that haven’t been soundly established through rigorous skeptical peer review. But if I were not an academic who trusts the peer review process, I’d probably look at the one-sided, uncritical discussion about global warming in the mainstream media and think it looks fishy — fishy enough to make room for conspiracy theorists to go to work.


    1. Agreed on the risk of academic group-think, driven in part by the thought-police activity of journal reviewers and funders. Both tobacco research and illicit-drug research have been badly compromised by the pressure for orthodoxy. (In the case of tobacco, one of the causes of that problem is precisely the fact that the cigarette industries paid for and promoted a massive campaign of obscurantism and outright lying – with strong resemblances to current global-warming denialism – that retarded sensible policy for decades, costing tens of millions of lives worldwide.)

      But there are two questions here: the scientific question of what is happening and the policy question of what is to be done. Nordhaus acknowledges the remaining uncertainties, though not (in this piece) specifically the medium-term trends Jon comments on, but goes on to make the essential policy point: given a greater-than-linear damage function, uncertainty calls for more action, not less.

      In a strange way, the existence of the well-funded global-warming-denial industry is reassuring. If there were actually any real doubt about the underlying fact of anthropogenic warming, there’d be someone to pay for a real study. But in fact what we have here is simply the marketing of doubt as a product by those who fear financial damage from sensible policy.

      Nordhaus points out the fallacy of the claim that skeptics are being persecuted in Lysenkoist fashion. But he misses the converse: denialists in office, including the Attorney General of Virginia, have threatened climate scientists with criminal penalties for their research, while less official actors are simply stealing and publishing their private communications, with the Brett Bellmores of the world cheering from the sidelines.

      It’s not entirely surprising if, under this sort of pressure, some of the scientists and their non-academic followers have departed from the path of perfect analytic detachment.

    2. Jon

      What would you have academics do?

      softpedal their message so it is ‘more acceptable’?

      Spend even more time allowing sceptics to ‘edit’ their work, to make it more ‘understandable’ or ‘acceptable’ by a ‘sceptical’ public?

      NOT say ‘this could be really bad, and it could happen faster than we think’ in the interests of making their opinions more ‘palatable’.

      I’d encourage you to apply these nostrums to the question of CFCs and the ozone layer, where academics more or less ignored the information in front of their faces (James Lovelock famously thought about it, and then rejected it– that the CFCs he detected could not get into the stratosphere in sufficient concentrations to have that effect). We even changed our satellite data, because what it was showing about the ozone layer had to be ‘noise’– our theories did not suggest a thinning could be happening (Lovelock is very good on this).

      If we’d simply soft pedalled the science on CFCs and ozone in the stratosphere, then we’d have wound up with a much bigger problem in the ozone layer, and consequences we still don’t know (the worst was a marked drop in phytoplankton levels under the hole– that’s the base of the world food chain right there).

      With GW, there won’t be some ‘Eureka’ moment when a British Antarctic Survey scientist thinks to measure the UV level and finds it is only consistent with a hole in the ozone layer. We won’t get that kind of unambiguous signal from the atmosphere.

      Instead we’ll get what we are getting: a steady rise in reported temperatures across the globe, but with strong local effects (eg a warming Arctic causing colder winters in Western Europe). And that rise is in line with what our models predict. Oh and we are getting extreme weather events: no way of telling if that is a structural shift or just cyclicality, but it is consistent with an atmosphere and oceanic system with more energy in it.

    3. Jon

      Just to quote Nordhaus below re statistics, in case you did not read the article Matthew Kahn cited, in full. This from the footnotes:

      For those who would like a sample of how statisticians approach the issue of rising temperatures, here is an example. Many climate scientists believe that CO 2-induced warming has become particularly rapid since 1980. So we can use a statistical analysis to test whether the trend in global mean temperature is steeper in the 1980–2011 period than during the 1880–1980 period.

      A regression analysis determines that the answer is yes, the rise in temperature is indeed faster. Such an analysis proceeds as follows: The series “ TAV t” is the average of the GISS , NCDC , and Hadley annual series. We estimate a regression of the form TAV t = α + β Yeart + γ (Year since 1980)t + εt. In this formulation, “Yeart” is simply the year, while (Year since 1980)t is 0 up to 1980 and then (Year-1980) for years after 1980. The Greek letters (α, β, and γ) are coefficients, while εt is a residual error. The estimated equation has a coefficient on Year of 0.0042 (t-statistic = 12.7) and a coefficient on (Year since 1980) of 0.0135 (t-statistic = 8.5). The interpretation is that temperatures in the 1880–1980 period were rising at 0.0042 °C per year, while in the later period they were rising at 0.0135 °C per year more rapidly. The t-statistic in parentheses indicates that the coefficient on (Year since 1980) was 8.5 times its standard error. Using standard tests for statistical significance, this large a t-coefficient would be obtained by chance less than one time in a million. We can use other years as break points, from 1930 to 2000, and the answer is the same: there has been a more rapid rise in global mean temperature in the most recent period than in earlier periods. ↩ [/quote]

  7. Brett: “None of the models, or so I understand, predicted the last decade’s stall in warming. They may have been tweaked after the fact to agree with it, but that’s not prediction.”

    Brett, ‘last decade’s stll in warming’ is last decade’s lie. I would ask you to stop lying, but it’s clear by now that if you did, you’d disappear in a puff of sulfurous smoke.

    1. At some point it’s either going to resume warming, you’re going to have to admit it’s stalled, or you’re going to look really stupid. I’d say that five or ten years will decide the matter. You can’t keep crying “statistical fluke” forever, or rely on statistically insignificant ‘warming’ to say there’s no stall.

      1. Care to cite any evidence for this stall you repeatedly refer to as if it were accepted fact? Seems to me you have it backwards and you are the one relying on statistically insignificant variations to say there is a stall. I don’t see any statistically significant bend in the global mean temperature trend over the last ten years, much less a leveling off, based on the chart of objectively sourced and rigorously verified data Nordhaus cites. The only way I see that is if one were to apply a peak-hold function in an improperly implemented attempt to separate the random noise from the trend. The peaks hitting +0.9 C have leveled off since 1999, but the overall trend inclusive of all the data continues upwards at roughly the same slope going back to at least 1980. Overlay a line representing the best-fit straight-line slope of the data measured from 1980 to 2000, and it fits well within the peak-to-peak noise of the data out to the end of the chart going to 2011. Where is your stall which you claim to be more statistically significant than the glaring warming trend represented by the data plotted on that chart?

      2. There is no evidence it has stalled. There’s interesting evidence about shorter term temperature cycles arising from the Pacific Oscillation.

        Which imply that we are close to the bottom of a temperature downcycle of roughly 10 years in periodicity. And yet average temperatures have kept rising.

        The next upcycle will be interesting, to say the least.

      3. Brett, what’s really hilarious here is not your lying; that’s normal now.

        What tickles me pink is that somebody, somewhere, might actually be paying you money to work as an engineer. I can imagine you in a meeting making a claim with no evidence whatsoever, repeating it endlessly while ignoring the people asking for evidence.

        It reminds me of the story I heard at [Big 3 auto company] where somebody was hired as a Ph.D. in electrical engineering, and fooled people for six months, despite having no training or experience in the field whatsoever.

  8. The irony in all of this is manifest.

    Richard Tol and Nordhaus have frequently combined to provide ammunition for climate sceptics of the kind who say ‘this is happening, or probably is, but what is the hurry?’ Tol is famous for the economic analysis to back that up eg we are better to adapt than to try to prevent climate change, etc.

    When Lord Nick Stern produced a report for Tony Blair’s government outlining the costs of climate change, and estimating them at 30% world GDP in 2050– ie the equivalent of another Second World War (or worse) Nordhaus jumped on him.

    Stern, Nordhaus said, was guilty of using a real discount rate of 1%. The correct rate, being that on US government real return securities, should be at least 4%.

    That was the Stern v. Nordhaus argument and it went on for over a year. Stern was the first widely acknowledged official report to put a cost on climate change, and Nordhaus became the prime ammunition for those, UK and otherwise, seeking to discredit it. Partha Das Gupta jumped in, saying Stern had undervalued the loss of life in frontier/ emerging market states that will feel the hit of climate change first, and hardest.

    Stern pointed out that since the ‘opportunity cost’ of losing an Earth as a habitable planet is essentially infinite, a very low pure rate of time discount is justified. This is not a conventional case of economic opportunity cost.

    Llomberg of course got his usual air time in the Wall Street Journal. Wouldn’t it be better if we spent that 2-5% of GDP (making the world economy in December 2050 no larger than it would otherwise have been in December 2048, but with of course much greater climate change) on providing clean water to everyone? The fact that the readers of the WSJ would oppose that and prefer to spend it on defence spending, and that human nature says we’d spend it on more and bigger cars and more cat food, is ignored. Llomberg is too shrewd a student of politics to get up in the WSJ and say ‘maybe we should do without defence spending’.

    Since then:

    – Stern has admitted he wished he had concentrated more on the ‘out cases’ the possibility that temperature change will be greater and or faster than our models project. What happens if we go up 5 degrees C, not 2? Or 10?

    In other words (and this is before the financial crisis hit) the ‘black swans’ or ‘fat tails’ of climate change, that our models might not predict– in the same way our Value-At-Risk (VAR) models did not prepare us for the financial events of 2008-09.

    – Nordhaus, to my knowledge, has not acknowledged that now that the real rate of return on long term government securities (UK or UK) is sub 1%, Stern is now arguably too aggressive in his discounting.

    In other words, Nordhaus had a great critique, it was widely used by advocates of doing nothing, and AFAIK he has not retracted it.

    In other words, Tol and Nordhaus have reached that level of the ‘useful idiot’. They don’t deny climate change, or that something should be done about it, but they provide excellent ammunition to those who do both or either.

    This makes Nordhaus’ article all the more ironic.

    I assume it is a sort of propitiation, the problem being that few people read a left wing literary publication like the New York Review.

    Freeman Dyson is in the same space, often writing in NYRB. It’s abundantly clear he has not done the homework on Climate Science, he just doesn’t like something detracting from his much greater ambitions of human space colonization etc. (he was estranged from his environmentalist son, which is interesting in this context). But because of his street cred as a physicist, he provides useful top cover to the denialists, or the ‘don’t do anythings, we have higher priorities’ crowd. Dyson more or less says ‘don’t worry, humans will create a super technology which will address global warming’.

    Oddly enough James Lovelock (arguably the greatest climate alarmist there is, as in ‘we are doomed. There’s no point doing geoengineering (a point he made to me personally at a talk last year in London) because we’d be no good at it. All green efforts are hopeless)’. That James Lovelock.

    Lovelock is also in some ways a ‘useful idiot’. Because his line is ‘we are doomed. And if only we had not opposed mass nuclear power, we would not be doomed’.

    That one ties together a nice couple of denialist/ do nothing threads: 1. there is no problem 2. it’s too difficult to do something about it 3). in any case, the only practical thing to do about it is nuclear power, wind will never work (the former might still be a good idea, but it’s an economic and political reality the US is not going to build 400 new fission reactors, nor any other country proportionately as many).

    When this crowd gets really heavy they bring up Nuclear Fusion aka The Tooth Fairy, 50 years from now.

    I despair of these guys: Nordhaus, Dyson, Tol even Lovelock. Because the only prudent rational course is to say:

    – it’s happening, as best our science can tell, in line with our predictions

    – it could happen faster, or worse, than we think, and that would be a huge danger

    – if we spend a lot of money preventing something that turns out to be less of a problem than we thought, it’s not more money than we spent on the Cold War in defence of a communist invasion which never came, and it’s not all wasted in any case

    – even if we do pull out the stops to do everything we can about it, turning a carbon using civilization around in its tracks, whilst still accomodating the demand (and moral obligation, in the case of much of the world) for a higher standard of living, will be supremely difficult

    Lovelock is not wrong when he says this is the summer of 1938, a particularly benign one. Thinking people realize what is coming after this warm summer, and are crossing their fingers hoping for the best. No one, at that time, except a few writers like HG Wells, imagined The Holocaust, or 30 million Russians dead. Or 10s of millions of Chinese (?) (not sure about the numbers there). Or the firebombings of Dresden and Tokyo and Hamburg, or the atomic attacks on Hiroshima and Nagasaki.

    That when it was over we’d count Yiddish Civilization as basically an extinct museumpiece. Or that Europe would be separated by an Iron Curtain for nearly 50 years.

    It’s 1938 in the summer of the world. Those wind turbines are the primitive prototypes of the Spitfires and Hurricanes we are going to need.

    I hope, when it is 1940 in the world of climate change, that we find our Churchill and our Dowding and our air defence system and our Chain Home Low radars. Because we are going to need them.

    1. “- if we spend a lot of money preventing something that turns out to be less of a problem than we thought, it’s not more money than we spent on the Cold War in defence of a communist invasion which never came, and it’s not all wasted in any case”

      I like this line of argument: A “War on Warming” could hardly be a bigger waste than the “Cold War”?

      1. Seth

        Consider that in the 1950s, US defence spending was c. 10% of GDP. OK there was a Korean War at the beginning.

        Similar levels prevailed during Vietnam (7-8% from memory). Yet these were periods of record economic growth when ‘muscular Keynesianism’ appeared to really work (problems re rise in underlying inflationary expectations– it wasn’t a perfect solution).

        Similarly when Ronald Reagan took power, the US engaged in one of the fastest increases in government spending in peacetime, Reagan raised the defence budget in double digit levels for his first 2 (or 3) budgets. Adding to the fuel of recessionary recovery (see Paul Krugman last few days with nifty charts on all this).

        The point being that 3-5% of GDP per annum, spent on anti global warming measures, is affordable.

        And of course you would rapidly hit diminishing marginal returns, so the actual Stern number is more like 2%.

        There would be some shadow costs: for example restrictions on CO2 emissions would create losses to the economy as a whole: see the new European car regulations about a fleet average of 135g CO2/ km– that’s costing over 300 euros per tonne abated (20 times the ETS market price of carbon). Some of the German solar subsidies have reached that kind of level.

        But again the evidence from the Clean Air and Water acts, and other programmes all of the world (eg US SO2/ Acid Rain abatement in the 1990s) that environmental regs have much lower costs than originally forecast: technology adapts to lower compliance costs. US cars now emit 10% of the pollutants they did in 1970, I don’t think anyone would advocate rolling back 40 years of EPA legislation.

        Over to the current state of the world economy. There are very few countries with meaningful full employment. There are slack resources aplenty (there would be bottlenecks in terms of electricity grids, skilled personnel etc.)– and even directly in manufacture and installation of insulation, solar panels, wind turbines etc.

        So no ‘crowding out’ right now on environmental investments.

        That will change, but it’s going to take 4-5 years (and maybe 10 years) before most major economies are back at full employment (which will itself expand with supply side capex and investment in skills etc.).

        The US still does not have as many employed as it did at the beginning of 2001. That’s a heck of a lot of underemployment.

        To the Cold War metaphor. We now know the Soviets had no serious plan to invade Western Europe except if they thought we were going to attack them. The country was internally quite weak, and the military strategy was configured around avoiding another totally destructive war on Soviet soil.

        But we did not know that then. So we overbuilt a deterrence (the generals wanted a far larger conventional one: Eisenhower refused point blank, saying it would cripple the economy), both nuclear and conventional.

        The West also, wastefully, got dragged into proxy wars (in particular Vietnam) that did not long run serve its strategic purpose. And this led it to ignore its real strategic vulnerability, a rising dependence on Middle Eastern oil, oil from people we don’t like, and who can disrupt our economies relatively easily– out appetite and involvement has contributed to the rise of an anti-western, anti-liberal fundamentalism.

        The lessons for Global Warming?

        – prevention that costs you 1-2% of GDP per annum (say the deadweight cost of the US nuclear arsenal above and beyond the 1000 or so warheads that exert deterrence on any other nation) is affordable

        – it might even be good for your economy– running more efficiently with the same inputs, moving closer to the full employment frontier, raising efficiency pushes that frontier out as well

        – a lot of it (eg electricity infrastructure) you have to do anyway: it’s a technology choice, rather than a ‘do we do this?’ We know we need new power stations and grid infrastructure

        – it might reduce your exposure to another strategic vulnerability: in this case, oil (in the long run it will, in the short run less clear, although efficiency is always a good thing)

        – in retrospect you might think ‘we did not need that’. But we know far more about the threat from global warming than, in retrospect, we did about the inner mind of the Kremlin (or what was for a time viewed as an even greater threat: the inscrutable Chinese)

        So British coastal fortifications built in the 1930s turned out to be irrelevant to the outcome of the war. But British airfields and radar stations and fighter planes and the system that linked them up? Decisive. Without Britain having held out in Summer 1940, there could have been no liberation of Europe, and (no Murmansk Convoys) probably no victory in Russia (unclear that) had the Nazis not been distracted by the peripheral wars with Britain: air war, U Boats, Mediterranean, North Africa, Atlantic Wall etc. Darkness would have fallen over Western Civilization, the world of George Orwell’s 1984 would not have been far behind.

        We know we have to change. It will be costly and difficult. But doing nothing is almost certain to be more costly, and in the case of the Summer of 1940, would have been fatal to Western Civilization. (a similar point could have been made about Roosevelt’s Two Ocean Navy Act, and also the decision to reinstate military conscription).

        So let’s act like it’s 1939 and get going. Lots of time to change our mind if the evidence changes (my bet, we’ll wish we’d done even more, and sooner: a purge on black carbon and some serious research into geoengineering would be high on my list of priorities).

        1. This is why I come back to articles that have scrolled off the front page when I have the time. Some of the most insightful comments are often left after the discussion has gone on for a few days, but sadly few people see them. It was well worth my time to come back to this thread and read this comment this morning.

          1. Freeman

            Thank you– much appreciated.

            Have you read the Robert Heinlein story ‘Free men’? Vintage RAH (for good and ill). (Cyril Kornbluth’s ‘Not this August’ also about an occupied America, is a very neat counterpoint: takes a conventional 1950s trope and does something with it–whereas Heinlein was invalided out of a peacetime Navy, Kornbluth carried at .50 cal MG at the Ardennes/ Bulge, and eventually the strain on his heart, then, killed him. The battle scene in NTA between the Russian KGB division and the American guerillas in the New York woods feels so real you could touch it).

            The old usenet threading meant the latest comments always came up, you could follow an argument for months, and down its sub branches.

            We have lost something here in the way blogs work.


    2. Note – during the late 1930’s, the Chamberlain government was working very hard on getting the Chain Home system up and running, and accelerating the introduction of the Spitfire.

      And considering that radar must have seemed like something fit only for HG Wells, this was an indication of just how worried they were.

      1. The debate about the Spitfire was around the cost: from memory, something like 2000 engineering man hours for a Hurricane, and 5000 for a Spitfire– the difference was the ellipsoid wing which made Spitfire such a deadly fighter.

        One faction argued for Hurricanes because they were cheap and available. But they would have lost the Battle of Britain: lacked that delta of performance to engage the ME109s in close combat.

        The whole creation of the ‘Dowding System’ of air defence was a masterpiece of civil-military cooperation.

        Originally the plan was to use audio monitors for incoming planes (big dishes carved into hill sides, with listeners). That proved insufficiently accurate– the radar came to save them.

        The CH and Chain Home Low (low level) systems had disadvantages: could not tell the height of the incoming aircraft. Many interception squadrons were ‘bounced’ from above, or flew too high and could not find their targets in the clouds.

        So the work of the Royal Observer Corps, ie ground spotters, was still important. And the Dowding System pulled all that info togethre from multiple sources into Fighter Command control at Stanmore in North London and regional centres. Civilians were asked not to tie up the phone system as the spotters used the civilian system to call in.

        And the interceptors went up. Handfuls of Hurricanes, Spitfires, climbing into the sky to face huge German fighter and bomber streams piloted by crack veterans of Spain, Poland, France.

        One German bomber pilot wrote in his diary of seeing a Hurricane, guns jammed, trying to ram him. And wondering what type of men was he fighting, that they would do that. That they would fight like that.

        There’s a line in Lois McMaster Bujold, the Barryarans (think 19th century Russian imperialists in space) are about to invade a planet, against the advice of the hero, Admiral Aral Vorkosigan. ‘Will they counterattack, Sir?’ ‘Of course they will counterattack. This isn’t some outpost. This is their *home* they are fighting for’. Captures it, I think.

        Churchill was prone to rhetorical exaggeration. But that line ‘never in the field of human conflict have so many owed so much to so few…’ has a truth to it. The Few.

        The Few. But backed up by dedicated civil servants and military officers on the ground, and scientists and engineers.

  9. re Jon Caulkins

    “But the climate community hasn’t managed to explain these 20-40 year long trends’ origin to people like me with a NY Times level knowledge of the issue.” BUT THEY HAVE. 20 minutes in a site like Real Climate would provide you a clear short explanation of the causes of variations in the different temperature series. Industrial pollution has been a major factor in lower surface temperatures than the straight CO2/water vapour forcing would predict. Climate science is not reading off a temperature guage and saying “well, it’s going up”. It’s taking known physical laws (which we use everyday in standard industrial applications), and building on their implication that more CO2 implies more water vapour implies more energy will be retained on earth. If we had this bit wrong, we would routinely be getting jet engines, power stations and soft-drink plants wrong. Where that energy will go, and what it will do, is the hard part. Which is why the debate in science is not about whether the earth is warming (it HAS too), but how fast and with what effects. On an issue like this, there is no excuse for anyone with a reasonable high school level of science being uninformed or in denial – despite the NY Times.

  10. “Nordhaus discusses the figure as if it shows upward long run trend + volatility, but that is not at all what I see. I see that plus also trends that last 20-40 years. Yes, there is a clear long run upward trend and of course there is random year-to-year variation, but I also see a downward trend from 1880 – 1910, up from 1910 – 1940, flat from 1940 – 1980, up from 1980 – 2000 and then there is the much debated 2000-2010. My eyeballs aren’t good enough to judge whether that 2000-2010 period is flat or still upward but only appears flat because of random variation. ”

    Go to Real Climate, or do a Google search, and find out about the ranking of warmest years on record. IIRC, a bunch of them are from the last decade.

    Frankly, the ‘warming trend has stopped’ is by now simply a lie. Back after 1998 (a positive blip in the data, and clearly visible and clearly explainable), people spent several years saying that it wasn’t getting warmer, because it took a couple of years for the trend to catch up.

    ‘The warming trend has stopped’ is a zombie lie, which will be rolled out every couple of years.

  11. BTW, I’ve skipped over a number of comments, and am lazy:

    Has Brett backed up his claim of a stopped trend yet?

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