PNAS: Peer Review or Old Boy Network?

by Marlo Lewis on September 23, 2009

in Blog

On February 25, 2009, Dr. James Hansen of Columbia University’s Earth Institute and Dr. John Christy of the University of Alabama in Huntsville testified on “Scientific Objectives for Climate Change Legislation,” before the House Ways and Means Committee.

Dr. Hansen is probably the world’s most influential scientist in the climate alarmist camp. His 1988 congressional testimony, which projected significant increases in global temperatures over the next two decades, gave birth to the warming movement.

At the Ways and Means hearing, Christy testified that datasets he and his colleagues have developed contradict the climate model hypotheses and surface temperature records on which alarmism rests. His leading example was the discrepancy between Hansen’s 1988 model forecasts and actual temperatures as measured by two independent satellite monitoring systems.


“GISS” A, B, and C are Hansen’s 1988 global warming model projections. “A” and “B” are model projections assuming business-as-usual emission levels similar to what happened (actually a bit lower than what occurred). ”C” is a model projection assuming drastic CO2 cuts. ”UAH” and “RSS” are, respectively, the University of Alabama in Huntsville and Remote Sensing Systems satellite records.

Christy comments:

All model projections show a high sensitivity to CO2 while the actual atmosphere does not. It is noteworthy that the model projection for drastic CO2 cuts still overshot the observations. This would be considered a failed hypothesis test for the models from 1988.

 Ancient history, you say? Maybe, but Christy also compared the IPCC Fourth Assessment Report’s (AR4) climate model warming projections with actual temperature data.


The red and orange lines mark the upper and lower bounds of 95% of the global warming projections calculated by 21 IPCC AR4 models for multi-year segments ending in 2020. The blue and green lines show temperature trends calculated from the UAH satellite record and the U.K. Hadley Center surface temperature record, respectively.

Christy comments:

The two main points here are (1) the observations are much cooler than the mid-range of the model spread and are at the minimum of the model simulations and (2) the satellite adjustment for surface comparisons is exceptionally good. The implication of (1) is that the best estimates of the IPCC models are too warm, or that they are too sensitive to CO2 emissions.

By now you may be wondering what any of this has to do with peer review at the Proceedings of the National Academy of Sciences (PNAS). Patience, grasshopper.

At the hearing, Hansen declined to address Christy’s critique of model sensitivity assumptions on the merits. Rather, he asserted that climate sensitivity is “crystal clear,” and advised the Committee to ask the National Academy of Sciences (NAS) to produce a report and accept its verdict as “authoritative.”

Now, if you’re like me, you probably assume that the National Academy insists on the most rigorous standards of peer review for PNAS, the organization’s flagship publication. But an article in the current (19 September 2009) issue of Science magazine (subscription required) suggests otherwise.

The article, “PNAS Nixes Special Privileges for (Most) Papers,” reports that:

National Academy members, as elite scientists, could shepherd their own work through peer review with less vetting than at other publications by “contributing” a paper. They could also “communicate” a paper on behalf of colleagues who had not been elected to the academy’s august ranks.

The article goes on to explain that:

In practice, “communicating” a colleague’s paper meant that a member lined up referees to review it before PNAS ever saw it. This increased the chance of a favorable reception — and looked suspiciously like cronyism to outsiders.

Because of that perception, PNAS announced last week that it will end the “communicated” option for submitting papers by July 2010. However, Science reports, “The move will not affect the privileges of academy members to line up reviews before they submit their own papers to PNAS …”

I don’t know about you, but my college GPA would have been higher had I been allowed to ”line up” friends to grade my term papers and tests. And wouldn’t it be nice if, during job performance reviews at work, we could “line up” allies to decide whether we deserve a raise and a bonus?

Science further reports that the “rejection rate for communicated or contributed papers that reach the PNAS is a few percent, whereas the rejection rate for standard submissions is 80%.” Membership doth seem to have its privileges at the National Academy.

Having spent a few years in institutions of higher learning, both as a student and a teacher, I have seen how our alleged bastions of academic freedom breed conformity and group-think. 

First, there’s the quest for tenure. A young professor serious about his career dare not challenge the methodological or ideological pieties of his colleagues, lest they deny him the coveted job security he seeks. And if the acolyte makes it into the ranks of the tenured, he will think twice about offending colleagues with whom he may be stuck for decades, and he’ll take care not to jeopardize his department’s research contracts and grants by offending the political pieties of grantmakers in Washington, D.C.

Most people admitted into the august ranks of the National Academy will have been shaped by the conformity mills that our institutions of higher learning have become. Moreover, once ensconced in the club, they will be loathe to offend other members, many of whom may have voted to admit them in the first place.

So it should come as no surprise that “the rejection rate for communicated or contributed papers that reach the PNAS is a few percent, whereas the rejection rate for standard submissions is 80%.” 

Even apart from these considerations, cronyism seems to be a significant problem in climate-related research. The IPCC reports are collections of literature reviews in which the lead authors often review their own work. Statistician Edward Wegman noted in his assessment of the infamous “hockey stick“ reconstruction of global temperatures (which allegedly proved that 1998 was the warmest year of the past 1,000 years) that “authors in the area of paleoclimate studies are closely connected and thus ‘independent studies’ may not be as independent as they seem on the surface.” 

So when National Academy member James Hansen declines to debate John Christy on the merits, and instead advises Congress to let the NAS decide the scientific basis of climate legislation, he is actually asking Congress to let the old-boy network to which he belongs call the shots.

That Hansen would proffer such self-serving advice rather than debate the core issue on the merits is reason enough to be skeptical of the science he espouses.

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