Murphy on Nordhaus

William Nordhaus recently published a long op-ed in the New York Review of Books that got quite a lot publicity. He in turn was responding to an op-ed in the Wall Street Journal. Nordhaus says,

But one of the difficulties I found in examining the views of climate skeptics is that they are scattered widely in blogs, talks, and pamphlets. Then, I saw an opinion piece in The Wall Street Journal of January 27, 2012, by a group of sixteen scientists, entitled “No Need to Panic About Global Warming.” This is useful because it contains many of the standard criticisms in a succinct statement. The basic message of the article is that the globe is not warming, that dissident voices are being suppressed, and that delaying policies to slow climate change for fifty years will have no serious economic or environment consequences.

My response is primarily designed to correct their misleading description of my own research; but it also is directed more broadly at their attempt to discredit scientists and scientific research on climate change.

So Nordhaus then addresses several questions

• 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?
As I will indicate below, on each of these questions, the sixteen scientists provide incorrect or misleading answers. At a time when we need to clarify public confusions about the science and economics of climate change, they have muddied the waters. I will describe their mistakes and explain the findings of current climate science and economics.

You’d think that was a valuable contribution. Now Bob Murphy has shown that Nordhaus was a bit naughty in his explanations.

Nordhaus identified six allegedly misleading claims made by the skeptics in their WSJ article, and proceeded (in his mind) to dismantle their bogus views. In the interest of brevity, I will in this post focus on just four of the claims. As we’ll see, it is Nordhaus who is playing fast and loose with the readers. Many of the objections raised by the skeptics are indeed legitimate.

The result is quite devastating. David Friedman and David Henderson have summaries.

I particularly enjoyed this bit of the Murphy critique.

It’s also interesting that Nordhaus invites his readers to not get caught up in the tiny details, and instead to take a step back and survey the grand picture of global temperatures. I agree. In that spirit, I suggest it can be misleading to focus—as Nordhaus does—on deviations of temperatures. Instead, let’s look at a graph of actual global temperatures, using the same three standard data sets that Nordhaus used for his own graph. (All we’re doing here is adding a base of 14 degrees Celsius to the deviations that Nordhaus plots.) The graph looks like this:

SOURCE: Data sets cited by Nordhaus, with 14C base global temperature added to deviations.

Seen in this light, it’s still true that temperatures of the last decade are higher than at any point since the late 19th century, yet this chart isn’t nearly as scary as the one Nordhaus showed.

To be clear, I’m not accusing Nordhaus of anything deceptive regarding the format of his temperature chart. There are good reasons that climate scientists tend to work with temperature deviations, rather than absolute levels.[1] Furthermore, without more information to guide our charting decisions, choosing a y-axis range of 0–20 Celsius degrees—as I’ve done in the graph above—is just as arbitrary as Nordhaus implicitly choosing a range of 14–15 degrees in the graph he used. Even so, when experts such as Nordhaus are presenting their material to the layperson, these nuances can get lost in the shuffle. Nordhaus thought his readers would “benefit from stepping back and looking at the record of actual temperature measurements,” and I agree.

I agree too. That graph is awesome and you’d have seen something like it before. Alex Robson and I created a graph like that in 2007.

As you can see not much has changed in the last 5 years.

Update: Due to popular demand I’m showing the second graph updated to the end of 2011.

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49 Responses to Murphy on Nordhaus

  1. Rabz

    As you can see not much has changed in the last 5 years.

    No we can’t – the graph cuts out at 2005.

  2. Rabz


    Let me clarify – if the last graph kept going until 2010 (at least), we’d be seeing a decrease in temperature.

    You’ve hidden the decline!

  3. Louis Hissink

    I’ll start getting interested when farming starts again in Greenland and the English start growing grapes where they were at the same time. Until that happens there isn’t any problem with the weather (climate) but we do have a clear and urgent problem with the gullibles who anticipate an ecological catastrophe, and I’m not sure how to manage that one.

  4. Sinclair Davidson

    Rabz – when you compare the two graphs …

  5. Iain Cook

    This graphical representation, range 0-30C,is actually a good way of looking at it. Around the world, yearly average temperatures where humans thrive range from about 30C (eg Bangkok, most of Saudi Arabia, parts of Africa) down to 0C or even less (Ulan Bator, capital of Mongolia, supposedly averages -16C). Hence it is misleading to imply that “humans are comfortable at 14.0C, and dying in their millions at 14.5C”. Just look at the death rates per hundred thousand in Australia – Brisbane’s is the same as Melbourne’s, yet the avergae yearly temperatures are nearly 10C different.

  6. Rabz

    Thanks Sinc,

    I’d still rather see the last graph go up until the end of last year.

  7. Sinclair Davidson

    Rabz – that last graph was published in 2007. A bit hard to go up to the end of last year.

  8. Rabz

    … that last graph was published in 2007. A bit hard to go up to the end of last year.

    Sinc, it’s 2012 – let’s see all the relevant data!

  9. Rabz

    let’s see all the relevant data

    It will prove our point, if nothing else…

  10. splatacrobat

    Can’t you add on a bit with the data already published up until 2012? I’m sure it would look better given that temperatures have remained static if not decreased during 2007-12.

  11. Sinclair Davidson

    Rabz – ffs. Look at the first graph for the latest data.

  12. Jim Rose

    this should be linked to the letters exchange between the warring parties.

  13. manalive

    Underneath the countless deposited layers of ossified bullshit is the fundamental IPCC thesis viz. “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”.
    But the global temperature rise c.1910- c.1945 (which was about equal in magnitude and rate to the post WW2 warming) could not possibly have been due to human CO2 emissions. And that is as far back as direct instrumental data (for what it’s worth thanks to Hansen and Jones) can take us.
    If the rising CO2 concentration is having any effect, it is empirically impossible to identify it.

  14. Over a period of thirty-two years the area of the Arctic Sea has decreased with what appears to be large variations. NASA emphasises that in the Arctic older and thicker ice is disappearing at a faster rate than thinner ice at the edges.

    The trend is clear and most likely needs to be related to a graphs displaying variations of mean air and ocean temperatures.

    How else can the contraction of Arctic ice be explained?

  15. Rabz


    lol – thanks, Squire!

  16. dover_beach

    manalive, excellent point. This is more or less part of Akasofu’s argument that the rise is simply rebound from the LIA.

    wmmbb, the answer may be in the wind.

  17. Embarrassing post Sinc that makes skeptics look like morons. If you want a flat graph why not plot it in degrees Kelvin? I will have to read the links though.

  18. Rabz

    Embarrassing post Sinc that makes skeptics look like morons.

    How exactly, moron?

  19. Sinclair Davidson

    laterite – I have been posting that graph for the last 5 years and always some numbnut asks the question, ‘why not graph in Kelvin?’

  20. Rabz

    That’s the best they’ve got?

    That’s why ‘we*’ all need to go back to living in caves?


    *Disclaimer: All animals are equal, but some animals are more equal than others…

  21. David Brewer

    Let me also recommend Jim Rose’s link, which contains a response to Nordhaus by members of the original WSJ sceptics team, and Nordhaus’ reaction:

    After carefully parsing both these later efforts, I reckon Nordhaus has been done like a dinner. The WSJ team make similar points to Murphy’s, but with even more cogency and completeness. Nordhaus’ long response is unworthy. He fails to answer most of the key points – that warming has stalled, that warming has been overpredicted by models, that his own ideal solution only averts 0.1 degrees of warming anyway etc.

    However, Nordhaus is great at playing the men instead of the ball. He points out that one of the authors used to work for ExxonMobil, and manages to repeat ExxonMobil six times. He accuses his opponents of waging a “bar-room brawl”, says they have “no special insights or results”, and compares them to a “campaigner who smiles benignly and says, ‘I would never call my opponent a Communist.'”

    Attempting to rebut the charge that industry funding of sceptical views is chicken feed compared to the billions financing orthodoxy, Nordhaus can only come up with the argument that ExxonMobil’s world-wide spending on the issue exceeds what his own university gets in US federal government grants alone.

    The exchange might well be worth another post to itself.

  22. dover-beach

    Thanks for the link. I am guessing global warming influences barometric pressure and wind variation. The North West Passage does not appear to have been open as it is now in the last five hundred years.

    The two data sets cannot be compared because of the different time scales, and the figures suggest the satellite observations began when the Arctic Oscillation was at a peak.

  23. dover_beach

    Stockwell isn’t a moron; he has done some sterling work eviscerating the work of the CSIRO/ BoM over the last decade.

  24. dover_beach

    I am guessing

    That would be a problem.

    The North West Passage does not appear to have been open as it is now in the last five hundred years.

    The use of ‘appear’ indicates another guess, and the appearance is contrary to some reports.

  25. Jim Rose

    thanks David Brewer, Nordhaus is and his critics too are too willing to question the other’s motives.

    critical discussion is based on the clash of ideas and argument. the environmental movement has motives, as do voters, comsumer, workers and business groups. the idea of debate is to see past motives and discover truth.

  26. Sinclair Davidson

    DB – he has indeed. Still trying to work out the Kelvin comment.

  27. Thanks again dover_beach

    Let me refer you – I was going to anyway – to Skeptical Science. The conclusion there:

    In sum, although natural factors have always influenced the state of Arctic sea ice, research strongly suggests that today’s decline is driven by the novel influence of anthropogenic CO2 we’ve added to the atmosphere and thus is unique in Earth’s history.

  28. dover_beach

    Sinc – I’m not sure myself.

    wmmbb – do they quantify the significance of natural and anthropogenic factors? And on what grounds can they say it is “unique”?

  29. Harold

    Who’s suggesting a 0 Kelvin base is silly? It actually makes a lot more sense as we then see it in terms of energy change.

    Recall how they like to say there will be “more energy in the system” when it warms? Yep, from 15 C to 17 C the change in Kelvin is 288.15 to 290.15, that’s a measure of energy change. Now make the simplified extreme weather increase extrapolations (as they do) based on that.

  30. dover_beach

    In the two of the three links to scientific publications that work, the respective conclusions support global warming as a distinct cause for the melting of the ice cap.

  31. Robert Murphy

    The range on your Y axis is so large that if you went back over the last few thousand years, you would barely notice the MWP or the LIA. Why not start at absolute zero and just visually eliminate most of the temperature change that has occurred over the lifetime of the Earth? There’s a reason that scientists scale their graphs the way they do – to present their data over a realistic range. The way you and Murphy have presented the data obliterates the information. With a graph with a y-axis that spans 30 degrees, even the depths of glacial eras would look innocuous. I’m almost ashamed to share the same name as Murphy.

  32. Sinc, Rabz: To change the range of the plot to 0-30 degrees is an arbitrary choice, Why not 0-10, 0-20, 0-100 or Kelvin which would range from 0-300. It makes no difference to interpreting the bad effects of a change in global mean temperature. The data is plotted as anomaly simply to fill out the space so that the small scale variation is obvious. Not to make it look scary. Replotting the data with a different scale says nothing about the potential effects of the change in temperature.

    When you just replot with a different scale and say “see nothing scary going on” it just sounds dumb. It would be like me plotting GDP on a scale x10 and saying “look, it doesn’t change as much as they say, what are economists getting upset about?”.

    Nordhaus’ point was a little more nuanced than yours.

    Also, a change in average global temperature is not comparable with a change in local temperature. A 0.1 change in a global average is not the same as a 0.1 change in the temperature outside, because it is comparing an average that smooths over variation and a data point with a different variance. So its another dumb skeptic argument to say that 0.5 will not matter because you cant feel the difference.

  33. Bruce of Newcastle

    Wmmbb – A few comments if I may. Firstly both Arctic ice and global ice area are presently above average in defiance of the IPCC claims and models.

    Secondly, almost all sceptics agree that the world had indeed warmed in the 20thC. But most sceptics will also point out that the other hypothesis explains this warming quite neatly, and especially the recent cooling…which again is in defiance of the IPCC sponsored models.

    The other hypothesis is of course the solar magnetic/low sensitivity hypothesis, for which there has been increasing numbers of peer reviewed papers in the literature, especially in the last year or two as sceptical climate scientists become less fearful of publishing (and the peer review system corruption is wound back). Some examples:

    Rao 2011
    Kirkby et al 2011
    Enghoff et at 2011
    Solheim et al 2011 and 2012
    Allan 2011
    Ludecke et al 2011
    Dragic et al 2011

    I could go on. These are just a few random papers I’ve saved, many others are around, not least Spencer & Braswell 2011, Lindzen & Choi 2011, Svensmark 2012 etc, which you will no doubt find addressed at SkS.

    In short, the CAGW view is rubbish, and the temperature profile since records began can be explained very nicely by solar magnetic and radiative changes in the past 350 years of recorded data, the influence of the great oceanic cycles and a sensitivity of about 0.7 C/doubling of pCO2. Which means CAGW is precluded given the logarithmic response.

    I would love to provide links to each dataset I mention here but that would waste Sinc’s time as this post’d go to moderation. So you’ll have to do with just the ice anomaly data and my own model page. The rest are easy to find, and I’d be happy to discuss them.

  34. Rabz


    Fair enough, but I still don’t regard the change in temperature as of any consequence.

    More importantly humans thrive in times of warmer temperatures and suffer in times of colder ones.

    It’s an hysterical beat up over nothing and the convenient commie ‘solutions’ particularly stick in my craw.

  35. Further to the above points on the significance of a change in global mean temperature, do skeptics realise this?:

    The largest temperature changes of the past million years are the glacial cycles, during which the global mean temperature changed by 4°C to 7°C between ice ages and warm interglacial periods (local changes were much larger, for example near the continental ice sheets).

    So, roughly speaking, a global mean temperature change of (to take the lower end) 4 degrees can mean the difference between huge ice sheets over North America and Europe.

    Yes it is a favourite skeptic game to pretend that a global increase of half of that will be no great consequence. Not to mention that an actual 4 degree increase has not been ruled out as a possibility under a business as usual scenario.

  36. Kirk Lazarus

    Something closer to home and perhaps more relevant to the current forum is today’s “impact statement” from the climate commission. Media reactions have been predictable

    Heatwaves, bushfires predicted to hammer NSW -ABC
    Climate Change to Bring Heat, Bushfires to NSW -BRW
    NSW is getting hotter: climate report -SBS

    None of the guardians of the public record has made the slightest effort to look into the data that allegedly supports the report. I spent maybe 30 minutes looking at the source of the data for one particularly scary graphic, Fig.3. This purports to show the trend rainfall over NSW.

    What it actually shows is the difference between rainfall in two years, 1970 and 2010. Why pick those years? The source is the BoM. Try changing the period selector. See which map has the least green on it. The one from 1970 to present.

    Attempting to judge a trend from two points is hazardous (especially when the points are chosen by someone else). If forced to do so, you maximize the chance of picking up the trend by choosing the points maximally far apart. Doesn’t look so scary, does it?

    A better way is to look at the whole time series. Here are the NSW rainfall anomalies with a 5 year smoothing line. This is just my qualitative take on the data, but it is my impression as a statistician that there is no significant downward trend in NSW annual rainfall over that period.

    I don’t believe that the presentation of data in that impact statement meets basic levels of scientific integrity.

  37. Rabz

    Not to mention that an actual 4 degree increase has not been ruled out as a possibility under a business as usual scenario.

    Not to mention the clunky and illogical structure of that statement, but if the individuals ‘not ruling out’ the 4 degree increase are hysterical warmy bedwetters, then yes, we can automatically rule it out.

    BTW, how do the convenient commie ‘solutions’ work?

    The air tax for example?

    Bleating about how long people should shower for?

    Banning certain types of light bulbs?


  38. PSC

    So, roughly speaking, a global mean temperature change of (to take the lower end) 4 degrees can mean the difference between huge ice sheets over North America and Europe.

    Yep – over several hundred years. And point #3 of the rebuttal is essentially that if the world ceases to exist in 2060, then there might be mild benefits to climate change. Let’s not worry so much about after 2060.

    I’m going to try this on my boss: Hi – I’ve got a great new trade. We borrow a bejeesusload of money, stock, sell options, get anything we can get our hands on. Then we assume that the world ends just before it all has to be covered. We’ll be cash-flow positive the whole time! We can’t lose!

  39. Helen Armstrong

    Doesn’t matter if the world gets warmer, anyhow, more land available for crops, grapes etc. Thus feeding the world is no longer a problem.

    Ditto CO2 increased benefit both growth and yield of crops, thus feeding the world.

    The above statements re warmth and CO2 are NOT cause and effect, merely, at best, weak correlation.

    Its damned lucky we discovered all that oil and coal to help out with the lack of food problem isn’t it? Sarc/

    The warmenistas (closely related to that other tribe, the sandalistas – although some argue they are one and the same) – they want no coal, no oil, hungry people, people in happy but spiritual food poverty – so the warmenistas can feel good about themselves.

    Nature worship – funny how those who practise it tend to imagine ‘perfect nature’ sans everyone but themselves.

  40. Bruce of Newcastle

    Steve – 2 C of warming would have no great consequence because all those enormous ice sheets have already melted.

    Furthermore we aren’t going to get 2 C of global anthromorphic warming because that would require pCO2 to increase by a factor of ten (give or take). There’s not enough economically recoverable fossil fuel to raise pCO2 to 3000 ppmV.

    That is what the measured data says. When the IPCC sponsored models include solar magnetic influence and ocean cyclic effects they will say the same, which is why the modellers don’t include these significant variables – if they did they’d be out of a job.

  41. 2 C of warming would have no great consequence because all those enormous ice sheets have already melted.

    What’s Greenland got sitting on it? Ice cream?

  42. Bruce J

    wmmbb and Dover_beach. Re you little bit above about the North West Passage not being open in the last 500years: . When BP were involved in developing the Alaskan oil fields in the late 1960’s, they were seriously considering shipping crude oil to the UK/Europe via the North West Passage and, I believe, ran trial voyages with icebreakers leased from the then Soviet Union.

    So the predictions with respect to the Arctic icefields were similar then, to those made in the past few years, i.e. The fields would shrink enough to make the North West Passage viable. And those 1960’s predictions were how accurate???

  43. Bruce

    Steve – Greenland ice cap is believed to be 2,850,000 km^3. The rate of melting by GRACE is about 240 km^3 per year, which I think is an over-estimate given temperature rises have been nil for the last 15 years.

    So that means we only have to wait until 13,887 AD before Greenland melts completely.

    I don’t think I’ll hold my breath in anticipation.

  44. Sinclair Davidson

    laterite – sure. Your second point is IMHO very different from your first. The fact is I agree with Bob Murphy’s argument – show people the temperature change in whole numbers in Celsius (or Fahrenheit or whatever scale they understand) and then ask them how much they are prepared to pay.

  45. Thank you Bruce of Newcastle for manner of your comment and trouble you have gone to explain and support your position. I appreciate the quality of your response.

    Scepticism is the appropriate scientific approach and the Earth’s climate is not a simple system. I will look at least some of your links, but it will take me time to get some understanding of the issues. I am reminded of Albert Einstein saying:

    “Everything should be made as simple as possible, but not simpler.”

  46. Gab

    Update: Due to popular demand I’m showing the second graph updated to the end of 2011.

    Pfft. It’s no good unless it’s in degrees Kelvin.

  47. Rabz

    Give that woman a grant…

  48. Bruce

    Wmmbb – Thanks. One paper I didn’t cite above as it is older is Butler & Johnston 1996. It’s worth a read too. I mention this as the analysis I did on sensitivity is a few years old now (I did it in 2009 when S&B 2010 came out in draft). I wanted to independently check the IPCC AR4 sensitivity value (median 3.1 C) vs that paper, which was pretty convincing, and B&J1996 gave me an idea how, since Armagh is near to the Central England Temperature triangle. The CET being the longest instrument record we have. After fitting the CET data in Excel the derived sensitivity came out at ~0.7 C. So of the two S&B 2010 was the winner. I’ve not seen anything yet to overturn this, indeed more recent results such as the CERN experiment further support it.

  49. Andrew Reynolds

    A video for you to “like” or “dislike”.

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