Geology & Geophysics Opinion

Red/Blue and Peer Review

Healthy skepticism has long formed the foundation of the scientific peer review process. Will anything substantively new be gleaned from a red team/blue team exercise?

By and

The U.S. Environmental Protection Agency (EPA) and the Department of Energy have recently proposed to use an alternative approach to standard peer review for evaluating climate change science, one that is patterned after the red team/blue team exercises developed in the military. In this approach, a red team attempts to penetrate a blue team’s defense. However, if the idea is to have the red team poke holes in the mainstream scientific community’s (the blue team) consensus on climate change, it discounts that such challenges have already been applied thousands of times while that consensus was gradually developed. A little history of climate science explains why.

We are old enough to remember when many, if not most, scientists were skeptical that the human impact on climate could be distinguished from natural climatic variation. The journey from the healthy skepticism that existed 40 to 50 years ago to today’s well-supported and widespread scientific consensus that humans are changing the climate is a remarkable story of the integrity of the scientific process.

The Long Journey from Skepticism to Consensus

Following theoretical predictions of the climatic effects of atmospheric carbon dioxide (CO2) made by Swedish chemist Svante Arrhenius in the 1890s, the first good observational record of increasing atmospheric CO2 began in the late 1950s as part of the International Geophysical Year. Modern climate science started in the 1960s, when general circulation models under development were modified to incorporate the effects of CO2 and water vapor to understand their impact on climate [Forster, 2017]. Not long thereafter, scientists systematically considered what else might explain the new warming trends that started in the 1970s and that continue today.

A number of hypotheses were evaluated from the 1970s through the 1990s. For example, solar scientists concluded that although solar variation (sunspot cycles) does modestly affect climate from one decade to the next, the effect is far too small and too cyclic to account for a multidecadal trend in warming. Similarly, other skeptical scientists hypothesized that expanding cities—with all their asphalt, concrete, and steel—were causing a heat island effect that could be influencing temperature measurements because weather observation stations that had at one time been outside cities had ended up being right in the middle of them. That hypothesis was also disproven, and surface temperature is now also measured on buoys in remote oceanic locations to minimize such an effect. Volcanoes were also studied both as warming agents from their CO2 emissions and as cooling agents from the particles they eject into the stratosphere. Scientific analysis showed that the former effect is very small relative to burning fossil fuels and that the latter effect persists only for a few years after the very largest subaerial volcanic eruptions.

By the end of the 1990s, these alternate hypotheses and others to explain late 20th century warming were carefully ruled out one by one, and consistent with an anthropogenic cause, early 21st century warming continues unabated with fossil fuel burning.

At the same time, a multitude of climate change trends became clearer, including higher surface temperatures and heat waves, melting Arctic sea ice, receding glaciers, rising sea level, changing patterns of extreme weather events, bird migrations, freeze and thaw dates of lakes, and so on. Confidence in our understanding of the climatic effects of massive releases of CO2 from burning fossil fuels since the beginning of the industrial revolution now converges from three independent lines of inquiry:

  • theoretical calculations of the greenhouse effect based on well-known physics and chemistry
  • fingerprinting the detailed patterns of climate change caused by different human and natural influences, such as differences among regional patterns of land surface warming, ocean heat content, and sea ice extent that are consistent with an anthropogenic effect
  • growing confidence in globally distributed measurements of climate change and its impacts and greater skill in matching those observations to increasingly sophisticated computer models that include the various land, ocean, and atmospheric greenhouse gas sources, sinks, and feedbacks

The scientific community has gradually shifted, on the basis of evidence, from predominantly being skeptical in the 1970s that the human fingerprint on climate could be demonstrated to today being convinced that there are no other plausible explanations besides the cumulative effect of the last 150 years of burning fossil fuel for the recent extent of changing climate. Natural climatic variation is ongoing, but it cannot explain the current speed and amount of observed change. The science does not stand still; studies on how clouds may moderate the rate of climate change and how aerosols (particulate pollution) affect clouds and can offset some warming, for example, are still areas of active research in which hypotheses are being tested and challenged with characteristic scientific skepticism.

Healthy Skepticism Is in Scientists’ DNA

The scientific process is built on healthy skepticism. To publish a paper in a scientific journal—whether in human health, geoscience, astronomy, or other areas—the author must openly declare any real or perceived conflicts of interest and convince a group of anonymous expert reviewers that the paper’s conclusions are supported by the data. Expert reviewers are asked to evaluate the strength of the evidence presented, and they, too, must declare any possible conflicts of interest that could lead to a real or perceived lack of impartiality, such as a financial interest in the outcome or a familial or institutional affiliation with the author. These safeguards promote rigorous and objective review, and peer review remains the gold standard.

In addition to peer-reviewed journals, overview assessments are periodically conducted and published by scientific societies and academies. For example, the National Academies of Sciences, Engineering, and Medicine convene panels and review committees in response to requests from government agencies and others to summarize the existing state of scientific knowledge on topics of societal concern. The resulting peer-reviewed reports are usually not prescriptive but, rather, are intended to frame and inform considerations of policy options with current scientific evidence. Transparent protocols are followed to identify and avoid potential conflicts of interest of panelists, to confirm their credentials, and to include a diversity of experiences and perspectives.

The deliberative process generates a report of where consensus among experts was reached and where differences of opinion remained, including publishing minority views. An excellent recent example of how seriously the Academy takes peer review is its review [National Academies of Sciences, Engineering, and Medicine, 2017] of a draft report by the U.S. Global Change Research Program describing the current state of climate science. Another review on the impacts of climate change on the U.S. economy, environment, and human health is expected later this year.

Other nations have conducted similar deliberative processes through their respective academies of science, as has the Intergovernmental Panel on Climate Change (IPCC) through its series of five assessments since the 1990s [Trenberth, 2015]. The IPCC assessment reports are reviewed by science experts and by government representatives, following formal and transparent protocols that seek consensus.

Questions About a Red Team/Blue Team Approach

The state of climate science today includes the vast accumulation of 50+ years of published papers and reports, each subjected to reviewers’ skeptical eyes to ensure that published conclusions are supported by data. This week, 16 scientific societies sent a letter to EPA Administrator Scott Pruitt to ask for clarification of what would be gained from a red team/blue team approach that peer reviewers didn’t already find in the vast body of climate science publications.

Beyond that overarching question, new procedural questions must be answered before applying the approach to science:

  • Will the team members be carefully and transparently screened by a neutral party for conflicts of interest, such as potential financial gain from influencing policies?
  • What scientific credentials and communication experience will be required of team members, and how will candidates be solicited and nominated?
  • Will the teams be encouraged to find scientific consensus where it occurs, and will there be a process for reconciling differences?
  • Is the proposed television venue for a red team/blue team debate, where TV personas could overshadow substance and time limitations can impede deep and thorough analysis, really appropriate for such important deliberation?
  • Will the team members be held to the highest standards of evidence in stating their positions, and if so, who will do the fact checking?
  • What sort of precedent will be established? Is this a one-off proposal targeting only climate science, or will it be applied to the scientific community’s research on vaccine safety, nuclear waste storage, or any of a number of important policies that should be informed by science?

The United States should be proud of our long tradition of objectivity, rigor, and scholarship, going back to well before President Abraham Lincoln’s signing of legislation that established the National Academy of Sciences. Our peer review and Academy report processes are not flashy or entertaining, but they are inclusive and tried and true and have helped build great institutions of science. They provide the evidence-based analysis of climate science and all other scientific disciplines that are so important for informing the public policy decisions that we rely upon to protect our security, health, safety, environmental integrity, and economic prosperity.


Forster, P. (2017), Half a century of robust climate models, Nature, 545, 296–297,

National Academies of Sciences, Engineering, and Medicine (2017), Review of the Draft Climate Science Special Report, Natl. Acad. Press, Washington, D. C.,

Trenberth, K. E. (2015), Intergovernmental Panel on Climate Change, in Encyclopedia of Atmospheric Sciences, 2nd ed., pp. 90–94, Elsevier, Amsterdam,

—Eric Davidson (email: [email protected]), President, American Geophysical Union; also at Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg; and Marcia K. McNutt, President, National Academy of Sciences, Washington, D. C. (email: [email protected])

Citation: Davidson, E., and M. K. McNutt (2017), Red/blue and peer review, Eos, 98, Published on 02 August 2017.
© 2017. The authors. CC BY-NC-ND 3.0
  • Mnestheus

    Administrator Pruitt’s choice of team leaders seems to have boiled down to Erik The Red and Harald Bluetooth, who have never received EPA grants

  • Ken Carslaw

    Another factor to consider in peer review is its transparency. Most peer review is still done behind closed doors, which is not conducive to building trust and consensus. Journals like Atmospheric Chemistry and Physics have pioneered open peer review in which reviewers’ comments and authors’ replies are freely available online. Admittedly, much of this material is never read by anyone, but the documented exchange becomes invaluable in contentious cases because it allows you to see the path towards consensus, or lack of it. Can you imagine a TV political debate in which you only got to see the closing statements rather than the whole discussion? Red team/Blue team or not, we need more transparency.

  • Deivis Bluznevičius

    We can not use current understanding of science. The concept of objectivity is wrong. There is no common view and an independent observer as understood in physics. Physics and chemistry deal with objects and materials not reality. Therefor claiming authority of academic review is not appropriate in the contest of our planet. We don’t live i.e. breath in and out on moon and scientists think that view from cosmos is true. To solve climate change we need to look at our planet as made up of one substance as waves and consider own body and thoughts as waves. Then we have to adjust waves or time of measurement and reporting to lift heat to the outer space or trap it in substances, to push cold to the poles and create perfect weather for all.

  • tolo4zero

    Many 97% consensus studies have been done, and none claim a 97% consensus on catastrophic, dangerous or even inconvenient warming.

  • tolo4zero

    I have quoted Kevin Trenberths opinion on deniers twice, and had my comments removed with no explanation.

  • philippe vidon

    I am wondering why there is concern about the blue team / red team approach that the EPA is proposing. Additional scrutiny on the possible causes of climate change can only reinforce the position that CO2 is the primary driver of global warming (right?), unless there are deficiencies in the lines of evidence advanced to support CO2 induced climate change that one does not want to be revealed. If we have confidence in our evidence of climate change as driven by CO2, we should welcome such a blue team / red team approach.

    • Jim Prall

      Simply, it is unnecessary and is a transparent delaying tactic. As long as they maintain the image that the issue of human causation is still up for debate, they can delay the required policy action – action that all nations already agreed in Paris are necessary. If they want to review the evidence, they could read any of the five huge literature reviews already done in the IPCC Assessment Reports (ARs)- or those of the US National Academies of Science – or those of several dozen scientific academies and learned societies around the world – or … etc.
      Starting a Red Team now is just rehashing what’s been gone over and over, for the past 30 years. Been there, done that, got the ARs.

      • Yep. The scientific community will also have to keep an eye on the US Global Change Research Program and the National Climate Assessment, which will surely be targeted for political interference.

        • philippe vidon

          I agree with you all in many ways. On the one hand, the blue team / red team exercise is not necessary because the science of climate change is solid. On the other hand, the reality is that there is a segment of the population that is still skeptical about climate change, and whether we like it or not, these people are able to delay action on climate because many seat in Congress. If the blue team / red team can help convince some of the people still wary of climate science, we need to do it. Indeed, i believe that where we fail as scientists is that we are not willing to reach out to non-scientists who may be skeptical of our science. We can shout all day to ourselves that the science of climate change is solid (and it is, i know), but if we don’t make the effort to reach out to the climate skeptics, then we are not better than they are when they deny climate change. If we need to explain climate change again, we owe to do it.

          • Given the administration’s position that climate change is a hoax, that CO2 is not the primary driver of recent climate change and its censorship of science, I feel confident that a blue team / red team exercise would be used to artificially inflate the misconception that there is ongoing scientific disagreement about the basic physics of climate change. I think reaching out to Congressional skeptics begins not with debating the science, but with working with the communities they represent, many of which are suffering from climate change. Explaining how climate policies can help those communities deal with flooding, disruptions to agriculture and other effects of climate change, in my experience, is more persuasive than trying to convince someone to accept the science for the sake of accepting the science. At the same time, getting more clean energy development online is proving persuasive in some areas. I think often of Iowa and how Sen. Chuck Grassley (R) talks about the state being rich in corn, hogs and wind. He notes that the wind turbines raise farm revenue, create jobs, and if you’re into solving climate change, it reduces those emissions, too. The Citizens Climate Lobby has probably done the most grassroots work on this front – they’re very impressive and committed. Additionally, electoral pressure from younger people may ultimately force politicians to drop their position of denial, but that will surely take longer!

          • charles0853

            Phillipe, what you say makes logical sense. But evidence suggests that
            logic and empirical evidence won’t win this ‘debate.’ Read the work of
            folks like Robert Brulle, Ed Maibach, Anthony Leiserowitz, Matthew Nisbet, Jonathan Haidt (Moral Foundations Theory), John Cook.

      • charles0853

        Absolutely right, Jim: a delaying tactic. Pretty obvious.

      • tolo4zero

        Have you added any more people to your black list?

    • I wouldn’t trust this administration to pull it off fairly or even coherently. In my mind, this idea is similar to the “voting fraud” commission – it’s using government resources to justify misinformation and bad policy instead of advancing the public interest.

    • charles0853

      I disagree. The red team members will be determined to make the case (wrongly) that there is no consensus and/or present arguments that have been repeatedly refuted. But all they need to do, in the EPA’s (Pruitt) eyes, is sown fear, uncertainty, and doubt. The the EPA can righteously say: no consensus, too early to act, need much more evidence.

    • Pruitt is most certainly interested in stacking the deck in favor of the fossil fuel companies that pay him massive amounts of money. There will be no chance it will be a well-balanced approach. The red team/blue team approach has been ongoing for decades and is well documented in the science literature and news reports. Why, then, does Pruitt want to retry what tens of thousands of scientists have already done?

    • han geurdrs

      What specific deficiencies could there be in the lines of evidence advanced to support co2 induced climate change?

  • tolo4zero

    Trenberth also worried about the debate approach:
    ” Debating them [“deniers”] about the science is not an approach that is recommended. In a debate it is impossible to counter lies, and caveated statements show up poorly against loudly proclaimed confident statements that often have little or no basis. Scientific facts are not open to debate and opinion because they are evidence and/or physically based. Moreover a debate actually gives alternative views credibility”

    He suugested a better way of dealing with skeptics:
    “So my feeble suggestion is to indeed cast aspersions on their motives and throw in some counter rhetoric. Labeling them as lazy with nothing better to do seems like a good thing to do.”