Why would you trust a magazine that doesn’t trust itself?  In a baffling display of ‘balance as bias’ – or perhaps ‘balance as baloney‘ – The New Republic has hired right-wing misinformer Jim Manzi to spread confusion about their articles.

Maybe magazines don’t bother employing fact checkers anymore, but when I coauthored the cover story for the Atlantic Monthly in 1996, “MidEast Oil Forever?” Drifting Toward Disaster, the magazine not only edited the piece, they made me provide a credible published source for every claim.  Even today, I know magazines like Wired fact-check every article.

But TNR appears to have proudly hired Manzi to un-fact-check their articles – at least in the area of energy and the environment, Manzi mostly spreads misinformation.   Indeed, as I will show, Manzi utterly misrepresents the important work of Harvard economist Martin Weitzman, which he discusses at length but doesn’t appear to know the first thing about.

I say TNR “proudly” hired Manzi because editor Franklin Foer has a June 22 column bizarrely titled, “The In-House Critics: Keeping TNR Honest” touting this self-inflicted wound to its credibility:  “it is an honor to be the subject of their criticism.”

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I know, you probably thought that the “center-left” magazine paid Foer and Martin Peretz and a slew of other editors (and, one hopes, fact checkers) to keep them honest.  How wrong you are!

As an aside, what’s doubly annoying is that you can read Manzi’s full on misinformation, “Why the Decision to Tackle Climate Change Isn’t as Simple as Al Gore Says,” in full here, but the piece he is nominally debunking, Al Gore’s, “The Crisis Comes Ashore,” from the June 10 TNR is behind their firewall.  You can read extended excerpts of Gore’s accurate piece here.

Manzi’s debunking has already been partly debunked by Time‘s Bryan Walsh and TNR‘s own Bradford Plumer.

UPDATE:  Things Break has chimed in with “Debunking Jim Manzi in 5 Easy Steps.”

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But Manzi’s analysis is much, much worse than all that.  Indeed, I was sent a debunking a few days ago by John Bruno that I’m reposting below.  I’ll add some extended comments of my own at the end.

Bruno is a marine ecologist, Associate Professor at The University of North Carolina at Chapel Hill, and currently a visiting scientists at the Global Change Institute at the University of Queensland. His research is focused on marine biodiversity, coral reef ecology and conservation and the impacts of climate change on marine ecosystems.  Here is his analysis:

Jim Manzi is a right-leaning former Lotus CEO, tech-guru and investor, a senior fellow at the Manhattan Institute and a contributing editor at National Review. He takes a lot of flack for telling his conservative friends and allies that they are wrong about climate change.  Manzi recently published an essay in The New Republic titled “Why the Decision to Tackle Climate Change Isn’t as Simple as Al Gore Says”. In Manzi’s words “The expected economic benefits of emissions mitigation do not cover its realistically expected costs.” Unfortunately, it isn’t nearly as simple as Manzi says either.

After taking a few shots at Al Gore, Manzi delves into the cost-benefit analysis regarding what the best (or most cost effective) response to climate change is; put simply – immediate emissions reductions or technological investments that would result in advances several decades from now in case warming gets truly catastrophic.  He cites an estimate from the IPCC on the economic costs of 4°C of warming by 2100:

“Even in the most extreme IPCC marker scenario (A1F1), the best estimate is that we should expect warming of about 4°C over roughly the next century. How bad would that be? [I think pretty bad, but more on that later]  Also according to the IPCC (page 17), a global increase in temperature of 4°C should cause the world to have about 1 to 5 percent lower economic output than it would otherwise have.”

Manzi combined this economic impact projection with an estimated emissions reduction cost based on values in a report from the economic think tank Resources for the Future.  Manzi argues that the average cost of limiting the increase of atmospheric CO2 to 450 ppm will be roughly 6% of global GDP by 2100.  With these two figures in hand, Manzi concludes we should forego attempts to limit emissions because that would cost slightly more (in percentage terms) than the economic benefits we would gain:

“That is, we would start paying a cost today that would rise to about 6 percent of world output by 2100 in order to only partially avoid a problem that would have expected costs of about 3 percent of world output sometime later than 2100.”

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Is the analysis really that simple and is this all the information we need to make an informed decision?  Obviously no to both questions.  Put plainly, Manzi’s analysis is flawed.

First, it is based purely on economics.  Obviously, there are many social, ecological, health and geopolitical costs that are not included in his argument. Social and governmental policy is made on much more than GDP projections, i.e., governments are not businesses. On page 16 of the IPCC report (Summary for Policymakers from working group II, IPCC AR4) that Manzi got the economic loss estimate from there is a figure (SPM.2, which I’ve included below) that outlines additional, non-financial impacts of 4°C of warming.  They include – hundreds of millions of people exposed to water stress, increased species extinction risk, widespread mortality of reef-building corals, reduced production of cereals in low latitudes, increased damages from storms and floods, a third of the world’s wetlands lost, millions of people experiencing coastal flooding, increased morbidity and mortality from heatwaves, floods and droughts, and “increasing burden from malnutrition, diarrhoeal, cardio-respiratory, and infectious diseases”.  Not exactly the rosy picture Jim “How bad would that be?” Manzi
paints.  This cheerful list suggests 4°C of warming would be pretty bad, certainly something to be avoided.  These and other non-economic impacts that will primarily occur in the developing world (and largely in the tropics) but are caused by the actions of wealthier countries, particularly America, must be taken into account in the policy analysis.  To ignore these impacts of our actions and decisions is amoral and would be astonishingly insensitive.

Second, even just sticking to the financials, Manzi’s argument is based only on the global mean economic loss and ignores the far greater losses some nations and regions will experience.  We Americans might save a buck by not reducing emissions, but that decision will cause considerable economic loss, impoverishment and misery elsewhere.  The cost to Americans might be just 3% of GDP (or more accurately, between 1 and 5%, but see more on this below), however, it will be far higher in nations with less adaptive capacity and where the physical impacts are going to be greater. Coastal nations with economies based largely on agriculture and fisheries will undoubtedly experience more than a 3% drop in GDP as sea levels continue to rise, shorelines erode and coastal villages have to be relocated, as fisheries dwindle, tourism drops off as coral reefs die from warming induced bleaching and disease, and drought causes inland crop failures.

From IPCC AR4:

“This Assessment makes it clear that the impacts of future climate change will be mixed across regions. For increases in global mean temperature of less than 1-3°C above 1990 levels, some impacts are projected to produce benefits in some places and some sectors, and produce costs in other places and other sectors. It is, however, projected that some low-latitude and polar regions will experience net costs even for small increases in temperature. It is very likely that all regions will experience either declines in net benefits or increases in net costs for increases in temperature greater than about 2-3°C [9.ES, 9.5, 10.6, T10.9, 15.3, 15.ES]. These observations confirm evidence reported in the Third Assessment that, while developing countries are expected to experience larger percentage losses, global mean losses could be 1-5% GDP for 4°C of warming [F20.3].”

IPCC impacts fig

The figure above is from page 16 (Figure SPM.2.) of the Summary for Policymakers from working group II, IPCC AR4 (which can be downloaded here).

Third, when the variance around the cost and benefit values in Manzi’s analysis is taken into account, there isn’t any difference between them. In other words, based on the available information, the 1-5% of GDP benefit is not different from the ~6% GDP cost.  Why?  Because there are enormous uncertainties about the economic impacts of any given global mean degree of warming.  IPCC is very clear about this, e.g., see here.  Also, I very much doubt that all the impacts on ecosystem services are taken into account in the IPCC economic impact estimate.  Costanza et al. (1997, Nature) estimated the annual value of ecosystem services is in the range of $33 to $54 trillion (in 1994 US dollars).  They stress that this is almost certainly a gross underestimate; the true value likely exceeds the current global market GDP of ~ $80 trillion.  Estimating the value of ecosystem services and modeling their projected losses due to climate change is notoriously difficult, hence the large range in estimated value. Costanza et al. also warn that “As natural capital and ecosystem services become more stressed and more scarce in the future, we can only expect their value to increase”, i.e., the economic losses caused by anthropogenic climate change will grow as natural ecosystems deteriorate.

table 1

On the cost of emissions reduction side of the analysis, there is even greater uncertainty that is obscured by Manzi’s “about 6%” figure.  Manzi apparently arrived at this value by averaging three model estimate means reported in Table 1 of the Resources for the Future report (Aldy et al. 2009. Designing Climate Mitigation Policy). The reported values were 1.4, 1.4 and 16.1; a pretty large range and a very small sample size.  The mean is indeed 6.3 but the standard deviation is 8.5!  Moreover, even Aldy et al. note “one striking feature in Table 1 [reprinted in part above] is the considerable variation across models within a stabilization scenario”

So Manzi’s whole analysis and conclusion is based on his comparison of the benefit (3% in GDP terms which he derived from the IPCC projected range of 1-5%) to the cost (6.3% averaged from the mean predictions of three models).  This is the analysis on which he expects us to make a policy decision that will affect the future of humanity and the fate of the earth!? Does Manzi not understand there is huge variance around these values? Does a former fortune 500 CEO really think economic projections of global GDP a century out have no error?

Moreover, will TNR publish a correction as countless outlets and organizations insisted the Washington Post do after it ran George Will’s untruthful essays about global warming?  (note Manzi fed The Economist the same crock of funny numbers last year here where he also trivialized the impacts of climate change by stating “anthropogenic global warming (AGW) is expected to cause economic costs of about 3% global GDP in a much wealthier world more than 100 years from now. This is pretty far from the rhetoric of imminent global destruction.”)

But wait, there is more!  For example, Manzi fails to note that Aldy et al. report that the cost to U.S. GDP is relatively small:

“U.S.-specific GDP losses are not reported in the studies in Table 1, but allocating a quarter of the global cost to the United States (based on its share in global GDP) implies a present value cost to the United States through midcentury of about $0.1-3 trillion (0-1 percent of the present value of GDP) for the 550 ppm target and $2-11 trillion (1-3 percent of present value GDP) for the 450 ppm target.”

actual vs IPCC emissions fig

We Americans caused most of this problem and we only have to sacrifice 2% (by Manzi’s logic) of national GDP through 2050 to keep emissions below 450 ppm?  Isn’t the decision a no-brainer?

Moreover, given the uncertainty of and variance around the cost and benefit values, one can only conclude that they are not different. Because there are countless additional non-monetary benefits to choosing action, e.g., reducing the probability of catastrophic warming, the obvious decision is to choose to reduce emissions immediately.

JR:  I would add that McKinsey 2008 Research in Review finds stabilizing at 450 ppm has a net cost near zero.  Bruno continues:

Another big problem with Manzi’s essay is that he wrongly labels the A1F1 scenario “extreme”, presumably assuming it is the least likely or a worse case scenario, and he somewhat misrepresents the warming estimates based on it. Manzi states: “Even in the most extreme IPCC marker scenario (A1F1), the best estimate is that we should expect warming of about 4°C over roughly the next century.” Yet A1F1 is the scenario recent emissions have been tracking most closely (see the figure to the right), which isn’t surprising since the social and geopolitical assumptions underlying it are among the most realistic of all the IPCC scenarios.


Furthermore, while ~ 4°C of warming by 2100 for A1F1 is considered the “best estimate” the “likely range” (in this case the 66% confidence interval) also has to be considered – these are after all probabilistic projections.  The upper range for temperature projections for 2100 based on A1F1 exceed 6°C, which translates to a ~ 10% decline in GDP based on the Nordhaus models that Manzi often favors.

Finally, it simply is not accurate or reasonable to assume that all or most emissions reductions are economically harmful. As Joe has been pointing out for years here on Climate Progress, there are a number of options to reduce emissions that will also reduce operating costs for business and benefit economies.

I’ll leave the more complicated flaws in Manzi’s analysis to Joe and actual economists like John Quiggen, both of whom have pointed out the dodgy nature of these shockingly simplistic cost-benefit analysis that are often highly flawed due to the huge uncertainties in the underlying economic assumptions, their ignorance of rare yet catastrophic events, their underestimation of warming projections and various problems with discount rates.  But this is all old news; so why are Jim Manzi and TNR still in the dark about it?


– John Bruno

The rest of this post is by Joseph Romm.

Let me amplify some of Bruno’s points about Manzi’s errors on the science and economics.

If Manzi knows the scientific literature well, he keeps it to himself . The science since the IPCC has evolved considerably, as I review here:  “An illustrated guide to the latest climate science.”  In a AAAS presentation this year, William R. Freudenburg of UC Santa Barbara discussed his research on “the Asymmetry of Scientific Challenge“: “New scientific findings are found to be more than twenty times as likely to indicate that global climate disruption is “worse than previously expected,” rather than “not as bad as previously expected.” It simply isn’t true that 4°C is the worst-case scenario.  Here are two of the best recent analysis of business as usual warming:

Obviously, the sea level rise estimates have jumped in most every recent study (see “Scientists withdraw low-ball estimate of sea level rise and “Sea levels may rise 3 times faster than IPCC estimated, could hit 6 feet by 2100

And if you really want the plausibly worst-case, go here:  UK Met Office: Catastrophic climate change, 13-18°F over most of U.S. and 27°F in the Arctic, could happen in 50 years, but “we do have time to stop it if we cut greenhouse gas emissions soon.”

And that why scientists led by a former co-chair of the Intergovernmental Panel on Climate Change issued a major report last year concluding the “net present value of climate change impacts” of $1240 TRILLION on current emissions path, making mitigation to under 450 ppm a must:

The real costs of adaptation are likely to be 2-3 times greater than estimates made by the UN Framework Convention on Climate Change (UNFCCC), say Professor Martin Parry and colleagues in a new report published by the International Institute for Environment and Development [IIED]….

The mean [annual] impacts in 2060 are about $1.5 trillion….  As usual, there is a long right tail, with a small probability of impacts as large as $20 trillion.

In the “aggressive abatement” case (450 ppm), the mean “Net present value [NPV] of climate change impacts” is only $410 trillion – or $275 trillion with adaptation.  So stabilizing at 450 ppm reduces NPV impacts by $615 to $830 trillion.  But the abatement NPV cost is only $110 trillion – a 6-to-1 savings or better.

The areas where the IPCC underestimated adaptation costs include water resources, health, infrastructure, sea level rise, and ecoystems.  Anyway, if you’re interested in the important stuff – the enormous benefit of stabilizing at 450 ppm – just jump to Chapter 8, page 103, here.

For a cost-benefit analysis of just focusing on US legislation, New York University School of Law’s Institute for Policy Integrity demonstrated last year that the Waxman-Markey American Clean Energy and Security A
ct (H.R. 2454) is “cost‐benefit justified under most reasonable assumptions about the likely social cost of carbon.'” In “The Other Side of the Coin: The Economic Benefits of Climate Legislation,” the Institute for Policy Integrity finds that the “benefits of H.R. 2454 could likely exceed the costs by as much as nine-to-one” (see “Waxman-Markey clean air, clean water, clean energy jobs bill creates $1.5 trillion in benefits“).

Now I and many others have long argued that traditional cost-benefit analysis doesn’t capture risk posed by the worst-case scenarios.  The economist who has most clearly delineated this in Harvard Martin Weitzman (see my 1/09 post Harvard economist: Climate cost-benefit analyses are “unusually misleading,” warns colleagues “we may be deluding ourselves and others”).

Manzi understand Weitzman’s work about as well as he understands climate science.  I am going to go into this at some length because it gets to the heart of why nobody should be paying attention to a Manzi critique, why no serious magazine should have him as their in-house critic.  Unlike Manzi, I have spent a lot of time going through Weitzman’s papers, emailing back and force with him, to try to understand what he is and isn’t saying.

Manzi starts by quoting Krugman on Weitzman:

You might think that this uncertainty weakens the case for action, but it actually strengthens it. As Harvard’s Martin Weitzman has argued in several influential papers, if there is a significant chance of utter catastrophe, that chance-rather than what is most likely to happen-should dominate cost-benefit calculations. And utter catastrophe does look like a realistic possibility, even if it is not the most likely outcome.

Weitzman argues-and I agree-that this risk of catastrophe, rather than the details of cost-benefit calculations, makes the most powerful case for strong climate policy. Current projections of global warming in the absence of action are just too close to the kinds of numbers associated with doomsday scenarios. It would be irresponsible-it’s tempting to say criminally irresponsible-not to step back from what could all too easily turn out to be the edge of a cliff.

So far so good.  Then Manzi says:

Krugman is correct, in my view, that: (i) a simple comparison of expected costs to expected benefits over the next century is an inadequate consideration of the economic trade-offs involved, (ii) uncertainty is central to the real decision logic, and (iii) increasing uncertainty in our forecasts strengthens the case for action.

The starting point for such a consideration is to recognize that we are not certain how much CO2 humanity will emit, how much warming a given amount of CO2 will cause, or how much damage a given amount of warming will cause. It is rational to reflect this lack of certainty by handicapping the possible levels of change and damage. Climate and economics modelers aren’t idiots, so it’s not like this hasn’t occurred to them. Competent analysts don’t assume only the most likely case, but build probability distributions for levels of warming and associated economic impacts (e.g., there is a 5 percent chance of 4.5 °C warming, a 10 percent chance of 4.0 °C warming, and so on). The economic calculations that comprise, for example, the analysis by William Nordhaus that I referenced earlier are executed in just this manner. So, the possibility of “worse than expected” impacts really means, more precisely, “worse than our current estimated probability distribution.” That is, we are concerned here with the inherently unquantifiable possibility that our probability distribution itself is wrong.

No.  This is wrong.  This is not what Weitzman is saying at all.

Weitzman believes the damage function is wrong quite irrespective of the probability distribution for levels of warming.  Weitzman believes that the damage posed by, say, 6°C is considerably worse than what traditional cost-benefit analyses calculate.

Weitzman says, that for any fat-tailed distribution, like the damage function for unrestricted greenhouse gas emissions, it is the possibility of extreme negative outcomes that overwhelm the traditional cost-benefit analysis.

fat-tail.gifThe extreme or fat tail of the damage function (click on figure at right) represents what Weitzman calls “rare climate disasters,” although as I’ve shown above, they aren’t rare at all, they are highly likely with business-as-usual emissions. For Weitzman, disaster is a temperature change (delta T) of > 6°C (11°F) in a century, as he explains in an earlier paper on the Stern Review on the economics of climate change:

Societies and ecosystems whose average temperature has changed in the course of a century or so by delta T > 6C (for U.S. readers: 6C = 11F) are located in the terra incognita of what any honest economic modeler would have to admit is a planet Earth reconfi…gured as science …fiction, since such high temperatures have not existed for some tens of millions of years….

With roughly 3% IPCC-4 probability, we will “consume” a terra incognita biosphere within a hundred years whose mass species extinctions, radical alterations of natural environments, and other extreme outdoor consequences of a different planet will have been triggered by a geologically-instantaneous temperature change that is signi…cantly larger than what separates us now from past ice ages.

Weitzman says the IPCC Fourth Assessment gives the probability of such an “extreme” temperature change as 3%, and that “to ignore or suppress the signi…ficance of rare tail disasters is to ignore or suppress what economic theory is telling us loudly and clearly is potentially the most important part of the analysis” – more important than the discount rate.

Manzi is totally confused on this point.  He writes:

The stronger form of the argument based upon uncertainty is not only that it is possible that the true probability distribution of potential levels of warming is actually much worse than believed by the IPCC, but that a reasonable observer should accept it as likely that this is the case. As Krugman indicates, the sophisticated version of this argument has been presented by Weitzman. Weitzman’s reasoning on this topic is subtle and technically ingenious. In my view, it is the strongest existing argument for a global regime of emission mitigation. (You can see a slightly earlier version of his paper, and my lengthy response here, along with links to the underlying source documents.) In very short form, Weitzman’s central claim is that the probability distribution of potential losses from global warming is “fat-tailed,” or includes high enough odds of very large amounts of warming (20°C or more) to justify taking expensive action now to avoid these low p
robability/high severity risks.

No.  As my excerpt of Weitzman’s work makes clear, it is fat tail around 6C warming that shatters the cost-benefit analysis.  Indeed, in his most recent paper Weitzman says again,

Six degrees of extra warming is about the upper limit of what the human mind can envision for how the state of the planet might change. It serves as a routine upper bound in attempts to communicate what the most severe global warming might signify, including the famous “burning embers” diagram of the IPCC [above] and several other popular expositions.

One recent study asked 52 experts for their subjective probability estimates of triggering a “tipping point of major changes” in each of fi…ve possible categories: (1) the Atlantic meridional overturning circulation; (2) the Greenland ice sheet; (3) the West Antarctic Ice Sheet; (4) the Amazon rainforest; (5) the El Niño/Southern Oscillation. For what it is worth, at an average temperature increase of T [approximately] 6C the expected (probability weighted) number of such expert-assessment tipping points was three (out of a possible …five).

It is 6C warming – and the multiple catastrophic outcomes it probably brings – Weitzman says you really, really want to avoid.

The main reason Weitzman spends any time talking about warming above 6C is merely to show absurd is the damage function used by traditional cost-benefit analyses.  Manzi is utterly clueless on this key point, and so he utterly misrepresents Weitzman’s work:

The big problem with his argument, of course, is that the IPCC has already developed probability distributions for potential warming that include no measurable probability for warming anywhere near this level for any considered scenario. That is, the best available estimates for these probability distributions are not fat-tailed in the sense that Weitzman means it. Therefore, Weitzman is forced to do his own armchair climate science, and argue (as he does explicitly in his paper) that he has developed a superior probability distribution for expected levels of warming than the ones the world climate-modeling community has developed and published. And his proposed alternative probability distribution is radically more aggressive than anything you will find in any IPCC Assessment Report-Weitzman argues, in effect, that there is a one percent chance of temperature increase greater than 20°C over the next century, while even the scale on the charts that display the relevant IPCC probability distributions only go up to 8°C (Figure SPM.6). It is not credible to accept Weitzman’s armchair climate science in place of the IPCC’s.

No, no, and no.  Weitzman believes he has developed a superior damage function for any given probability distribution of expected levels of warming.

Weitzman would laugh at the notion that his conclusions are based on the possibility we would warm more than 20°C.  Heck Weitzman’s new paper says, “I arbitrarily take 18C (3 x 6C) to be an upper bound beyond which temperatures are not allowed to go –by …- by fiat.”  You can look it up.  Manzi obviously didn’t.

Manzi simply doesn’t understand the first thing about Weitzman’s work and so he utterly misrepresents it.

Now the other key error Manzi makes, as I’ve discussed, concerns the probability distribution for expected levels of warming.

For me, what is especially important about Weitzman’s analysis is that the science is now crystal clear that there is far greater chance than 3% chance we will have a total warming of 6°C in a century or so if we don’t reverse emissions trends soon.

Again, you can go here: “Hadley Center: Catastrophic 5.5-7°C warming by 2100 on current emissions path.”  Or look at MIT 2009 analysis:


As Andrew Freedman at washingtonpost.com explained:

For the no policy scenario, the researchers concluded that there is now a nine percent chance (about one in 11 odds) that the global average surface temperature would increase by more than 7°C (12.6°F) by the end of this century, compared with only a less than one percent chance (one in 100 odds) that warming would be limited to below 3°C (5.4°F).

To repeat, on our current emissions path, we have a 9% chance of an incomprehensibly catastrophic warming of 7°C by century’s end, but less than a 1% chance of under 3°C warming.

“The take home message from the new greenhouse gamble wheels is that if we do little or nothing about lowering greenhouse gas emissions that the dangers are much greater than we thought three or four years ago,” said Ronald G. Prinn, professor of atmospheric chemistry at MIT. “It is making the impetus for serious policy much more urgent than we previously thought.”


Manzi doesn’t get any of this at all.  His understanding of climate science, solutions, and economics is very thin and often completely wrong.

But by bringing him on as an “In-House Critic,” The New Republic has essentially given a vote of no confidence to the articles that they do publish – and to the editorial team they assign to ensure the accuracy of that piece.  If The New Republic believes their articles are so flawed that they need a serial misinformer like Manzi to keep them honest, why should you bother reading them in the first place?

– Joseph Romm