Screwups in Climate Science

by Bill Chameides | February 22nd, 2010
posted by Erica Rowell (Editor)

Permalink | 8 comments

Recent events have given climate science a black eye, but nowhere near the knockout punch depicted in the media.

E-mails documenting overly partisan behavior on the part of a group of climate scientists should not and cannot be dismissed out of hand. To be sure, those involved have had to contend with unrelenting attacks by climate skeptics, but that’s no excuse. It’s time for a little self-reflection on the part of the climate science community and a renewed affirmation of our commitment to the scientific method.

Similarly, the revelations of errors and poor scholarship in the latest assessment of the Intergovernmental Panel on Climate Change (IPCC) are serious, although not surprising given its sheer volume (four separate reports totaling almost 3,000 pages) and the number of scientists who helped prepare it. Perhaps more damaging was the initial response by IPCC chairman Rajendra Pachauri who, rather than calmly considering them, called the reported errors “voodoo science.” The IPCC should assess its own mission, organization, and procedures before undertaking its next scientific assessment.

These mistakes are unfortunate and disappointing, but their depiction in much of the blogosphere and media has grossly overblown their significance. Here are two examples where media outlets have fallen well below their own standards for accurate, objective reporting.

On Tricks and Hiding in Hacked Messages

Much has been written about the e-mail hacked from Phil Jones, director of the University of East Anglia’s Climate Research Unit, that mentions using a statistical “trick” to “hide the decline.”

The use of the word trick has been interpreted as evidence of nefarious data-manipulating. Unlikely. Trick is a term of art commonly used in statistics and science as shorthand for a clever, elegant method. For example, on February 14, 2010, a New York Times piece on advances in biotechnology reported that a “firm … similarly tricked out yeast to produce an antimalarial drug.” No suspicions of underhandedness there.

The words “hide the decline” have been widely suggested to mean that scientists colluded to obscure falling temperatures, specifically those purportedly from the first decade of the 2000s. This is simply wrong.

  1. The e-mail in question, written in November 1999, came hot on the heels of arguably the warmest year on record (1998). So what decline would they be hiding?
  2. A careful examination of the messages’ content, including “Mike’s trick,” reveals that Jones was referring to a poorly understood decline in the density of tree wood, starting in the 1960s, that causes the temperatures inferred from tree rings in the 20th century’s later years to diverge from the instrumental record. To be sure, this divergence is not a welcome development for scientists like those at the University of East Anglia who have been using tree rings to infer temperatures over the past millennium. Perhaps in hiding the divergence they were trying to make the results look cleaner. But they could not have been trying to cover up any data. The divergence was already well known among climate scientists and discussed in detail in the scientific literature (e.g., here and here).
  3. Finally, for the record, there has been no long-term decline in global temperatures. Temperatures in the first decade of the 2000s were higher on average than those of the ‘90s.

So why so many misinterpretations of Jones’ and his colleagues’ intention? Perhaps the reason is that so many press items placed the word “temperature” directly after the phrase “hide the decline.”

  • Here’s an example from the New York Times: “Jones … said he had used a ‘trick’ … to ‘hide the decline’ in temperatures.”
  • And another from the Washington Post: “he had used ‘a trick’ to ‘hide the decline’ in a chart showing global temperatures.”
  • This from a Wall Street Journal opinion piece: “In [the e-mails] scientists appear to … give tips on how to ‘hide the decline’ of temperature in certain inconvenient data.”
  • And this from a Washington Times editorial: “Mr. Jones talked to Mr. Mann about the ‘trick of adding in the real temps to each series … to hide the decline [in temperature].’”

Were these pieces intended to mislead the public? I have no idea. Did they end up misleading? I believe so. (To their credit, some media reports got this right. See here.)

Himalayan Meltdown

The IPCC incorrectly stated the near-term fate of Himalayan glaciers with this: “Glaciers in the Himalaya are receding faster than in any other part of the world … and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035 (WWF, 2005).” We now know that this was inaccurate [pdf] and that the IPCC review process [pdf] failed to catch the error.

The media have accurately reported such details, but what’s been left out — the whole story — has led to misconceptions by lots of people I’ve spoken to.

The statement that Himalaya’s glaciers will vanish in a few decades was clearly not the IPCC’s consensus finding. By my own count, the assessment discusses their fate in three other places, all in a much more nuanced, more accurate, and less alarmist context.

Here’s an example from the IPCC summary for policy makers which prefaces the report containing the error: “Glacier melt in the Himalayas is projected to increase flooding, and rock avalanches from destabilised slopes, and to affect water resources within the next two to three decades. This will be followed by decreased river flows as the glaciers recede.”

The Bottom Line

Did the IPCC make a mistake? Yes? Are such mistakes of concern? Absolutely (especially in light of revelations of other errors). But does this undermine the entire assessment’s credibility? I think not. Are the mistakes a sign of a concerted effort to mislead the public? Hardly.

The worst thing we scientists can do at this point is contend that these missteps are inconsequential. But it’s egregious for the media, through inaccurate inference, exaggeration, and a failu
re to give all the facts, to over-blow their significance. Doing so will undermine and erode public confidence in the state of our understanding of global warming. In fact the scientific evidence that the globe is warming and that this warming is connected to human activities remains strong.

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  1. Ken Towe
    Mar 11, 2010

    “…it would be difficult for a study back in the 1970s to have used that baseline, do ya think?” Of course, but that’s the important point, Bill. While rates of change are independent of a reference or baseline the later studies keep changing the baselines. In 1987 Jim Hansen arbitrarily set the zero-point for 1951-1980 at 14°C (see his Fig. 16). Apparently, the “normal” 15°C for the 70s wasn’t appropriate? Phil Jones uses 14.6°C for the NH and 14°C for the globe. NCDC-NOAA used 15°C and a base period 1961-1990 in 1998, but now uses 13.9°C? Why? Once you have created an appropriate baseline for an anomaly analysis, it seems sensible not to change it mid-stream, does it not? The direct measurements (thermometers) are the raw data, the basis for ALL of these anomalies. What was considered “normal” in 1910 is now deemed 0.5°C below normal? How so? What was considered ‘global warming’ from 1920 into the late 30s is now viewed as just getting back to normal? It is the changed frames of reference that seem to have been lost in the shuffle. Re-read my March 2nd comment on ‘Climate Reality…’ and my March 3rd comment on ‘Warming is Unequivocal’ post. Please explain. Simply saying that the various graphs are consistent, while true, is misleading and doesn’t really help us move on. PS. Ice-age discredited? Yes, Cooling discredited? No… we just changed the reference baseline.

  2. Bill Chameides
    Mar 11, 2010

    Ken, Haven’t we been through this several times in the past? 1. You can’t compare the ACTUAL VALUE of the temperature anomaly at any point in time between these various graphs since they USE DIFFERENT BASELINES. For example, for the graph included in my post the baseline was the period between 1951 and 1980 — it would be difficult for a study back in the 1970s to have used that baseline, do ya think? 2. Having said that, the various graphs you refer to are consistent. For example, they all show ~0.4 degree C increase between the 1st decade of the 1900s and the 1940s. 3. The 1970s ice-age red herring has been discredited many times, by many people. Let’s move on, shall we?

  3. ron beltramini
    Feb 23, 2010

    Peter with all do respect, these are the same type of dire predictions used in the 70’s to alert us to the mini ice age we were entering. Remember? My god Peter they were growing grapes in Scotland 300 years ago. Pretty good wine from the research I have done. The sun and it’s cycles is the true driving force regarding climate change. If you want to debate the issue, which is the getting off of a carbon based energy model, fine. You are trying to mix apples and oranges otherwise. Remember the most important element is all of this. If anyone can control one of the four elements needed for life on the planet, you control humanity. It is that simple Peter. All about control by a very select few.

    • Bill Chameides
      Mar 2, 2010

      Ron: read the literature. The scientific community was not in consensus that there was a mini ice age approaching in the 1970s. You can check out my earlier posts on the subject ( and ). And by the way, they are growing grapes in Scotland today as they do in England.

      • Ken Towe
        Mar 6, 2010

        “The scientific community was not in consensus that there was a mini ice age approaching in the 1970s. You can check out my earlier posts on the subject…” It is important to point out, again, that the temperature anomaly chart figured in that earlier post (like others today) does not reflect the data that were being evaluated in the 70s. Those are shown in the chart put out by the National Academy of Sciences in Figure A.6 from their 1975 report “Understanding Climatic Change”: A program for action. The data were discussed in the Nat’l Geographic article “What’s Happening to our Climate Chart located at: 1976 quotes from Dr Reid Bryson: “… I believe we’ve put together an equation which reproduces what should have happened and what actually did happen to the Northern Hemisphere’s temperature during the last century. We find that, since 1945, the Northern Hemisphere has cooled one half of one degree Celsius.” “Rodewald, for example, studied the measured water temperature of the North Atlantic and found that—from 1951 to 1972—it dropped quite dramatically. It went down rather steadily throughout the 50’s, leveled off somewhat during the 60’s, then started down again.” But the best?: “We’re not looking for something that tells us, ‘Oh boy! It’s going to get cold everywhere,’ or ‘Wow! It’s going to get warm everywhere.’ That’s not the way the climate behaves.” Might want to pass this along to Mr. Gore next month? There were climate alarmists back then too…but it was cooling… unequivocal cooling.

  4. Syd Baumel
    Feb 23, 2010

    Very soon after “climategate” erupted, one of the best youtube counterparts to this excellent blog posted an outstanding video in which he, among other things, chased down and photographed multiple instances of “trick” being used as accepted jargon in the titles of papers in major science journals: . The amount of reckless reporting, much less ignorant bloviating, in the mainstream media about climategate, IPCCgate et al. is indeed outrageous – and depressing when you consider how much public diseducation on such a vital issue has taken place. I hope the damage done to public acceptance of AGW won’t end up being as massive as the economic destruction wrought by the debt gamblers. If there’s a silver lining, hopefully this crisis will cause the climate science community to rethink and upgrade its strategies of public education. It needs to go on the offensive.

  5. Bill Chameides
    Feb 22, 2010

    Peter: you make a good point, but what makes an organization like the National Academy of Sciences so trustworthy is the intentionally slow and measured approach they take to addressing any issue.

  6. Peter G
    Feb 22, 2010

    Good points! Yet scientists continue to take far too long to respond to all the distortions. See

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