Expert credibility in climate change: not all climate research and expertise are equal.

A fairly convoluted (but interesting none the less) paper just got published in PNAS by Anderegg et al (2010) looking at climate change and scientific credibility (more coverage by the Guardian here). Why don’t we trust climate scientists? To answer this question, the authors conducted a literature search of 1,372 climate researchers whose work “constitutes expertise or credibility in technical and policy-relevant scientific research”, and conclude what we’ve been blogging here for some time: “Despite media tendencies to present both sides in debates, which can contribute to continued public misunderstanding,not all climate researchers are equal in scientific credibility and expertise in the climate system

Although preliminary estimates from published literature and expert surveys suggest striking agreement among climate scientists on the tenets of anthropogenic climate change (ACC), the American public expresses substantial doubt about both the anthropogenic cause and the level of scientific agreement underpinning ACC. A broad analysis of the climate scientist community itself, the distribution of credibility of dissenting researchers relative to agreeing researchers, and the level of agreement among top climate experts has not been conducted and would inform future ACC discussions. Here, we use an extensive dataset of 1,372 climate researchers and their publication and citation data to show that (i) 97–98% of the climate researchers most actively publishing in the field support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.

Here’s the nuts and bolts of the paper (CE = convinced by the evidence, UE = unconvinced by the evidence):

So: not only is there a pretty considerable difference between the number of expert researchers between CE and UE groups, the mean expertise of the UE group was around half (60 publications) that of the CE group (119 publications). Here’s the real interesting statistic: researchers with fewer than 20 climate publications comprise ≈80% the UE group, as opposed to less than 10% of the CE group. To quote the authors: “This indicates that the bulk of UE researchers on the most prominent multisignatory statements about climate change have not published extensively in the peer-reviewed climate literature.

From a subsample of the 50 most-published researchers from each group, there was a considerable difference in relative expertise between the CE and UE groups:

Of these top 50 researchers, the CE group have an average of 408 climate publications, whilst the UE researchers averaged only 89 publications. Again, to quote the authors. this suggests that not all experts are equal, and top CE researchers have much stronger expertise in climate science than those in the top UE group“.

So who’s citing who? Anderegg et al use citation metrics to determine “…the quality and impact of a researcher’s contribution—a critical component to overall scientific credibility—as opposed to measuring a researcher’s involvement in a field, or expertise“. In examining the top four most-cited papers for each CE and UE researcher with 20 or more climate publications, the disparity in citation metrics between the CE and UE groups is astonishing:


(i) 97–98% of the climate researchers most actively publishing in the field support the tenets of Anthropogenic Climate Change (ACC) outlined by the Intergovernmental Panel on Climate Change

(ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.

As Phil M commented on a post the other day, the UE group:

1) Also happen to have close ties to fossil fuel & mining industries.
2) Have ties to right wing lobby groups.
3) Have only a handful of scientists who back the denier side, of whom few have published or conducted research in any relevant climate science field, much less publish any papers in reputable journals debunking AGW.
4) Have not a single scientific instituion backing them.

Anderegg W.R.L., Prall J.W., Harold J. & Schneider S.H. (2010 Online Early) Expert credibility in climate change. Proceedings of the National Academy of Sciences 21 June 2010, doi: 10.1073/pnas.1003187107

8 thoughts on “Expert credibility in climate change: not all climate research and expertise are equal.

  1. CSIRO, BOM & the Academy of Sciences have banded together to address the tide of denialism pervading our media recently.

    WUWT has been surprisingly dismisive of their slide show. Who would have thought:

    Here are the slides that has got them so upset.

    Thumbs up to Luke for saying what many of us think:

    Luke says:
    June 19, 2010 at 8:56 pm
    But do the sceptics ever ask to make a presentation to CSIRO or the Bureau of Meteorology. Nope – the rule is never engage where serious questions will be asked.

    It’s just sideline sniping guys and avoids any serious review of your position. Audiences of retirees are much easier aren’t they?

    Good job all round Luke, amazing you werent censored.

    Sadly comments like this below reflect why deniers think they are part of the debate:

    Amino Acids in Meteorites says:
    June 19, 2010 at 9:01 pm
    “Scientific journals have rigorous peer review”

    They don’t know what rigorous is until they’ve been through WattsUpWithThat, ClimateAudit, Lucia’s Blackboard, Lucy Skywalker’s, JeffID’s, Musings from the Chiefio, SPPI, etc., etc., etc.

    Science by blog & scrutiny by amateurs, thats the way. You can count on one hand the amount of active UE scientists & will rarely see their names in one of these journals:

    Most-Cited Journals in Climate Change Research, 1999-2009
    (Ranked by citations to papers published and cited between 1999 and 2009)

    Rank Institution
    1 Nature 22,952
    2 Science 21,791
    3 Global Change Biology 12,013
    4 Journal of Climate 11,778
    5 Geophysical Research Letters 10,500
    6 J. Geophysical Research Atmospheres 9,826
    7 Climatic Change 8,423
    8 PNAS 7,484
    9 Climate Dynamics 5,761
    10 Quaternary Science Reviews 5,470
    11 Ecological Applications 4,252
    12 Ecology 4,041
    13 Int. J. Climatology 3,650
    14 Earth & Planetary Science Letters 3,554
    15 Ecological Modelling 3,482


    Journals Ranked by Impact: Meteorology & Atmospheric Sciences

    Rank 2008 Impact Factor Impact 2004-08 Impact 1981-2008
    1 Bulletin of the American Meteorological Society
    (5.25) Journal of Climate
    (8.64) Bulletin of the American Meteorological Society
    2 Atmospheric Chemistry and Physics
    (4.93) Bulletin of the American Meteorological Society
    (8.04) Global Biogeochemical Cycles
    3 Journal of Climate
    (4.31) Atmospheric Chemistry and Physics
    (7.49) Journal of Climate
    4 Global Biogeochemical Cycles
    (4.09) Climate Dynamics
    (7.41) Journal of Climate & Applied Meteorology
    5 Climate Dynamics
    (4.05) Journal of Applied Meteorology
    (7.30) Journal of the Atmospheric Sciences
    6 Agricultural & Forest Meteorology
    (3.67) Global Biogeochemical Cycles
    (7.17) Atmospheric Environment Part A – General Topics
    7 Climatic Change
    (3.20) Journal of Hydrometeorology
    (6.79) Journal of Geophysical Research – Atmospheres
    8 Journal of the Atmospheric Sciences
    (2.99) Agricultural & Forest Meteorology
    (6.77) Monthly Weather Review
    9 Journal of Hydrometeorology
    (2.95) Journal of Geophysical Research – Atmospheres
    (6.41) Journal of Atmospheric Chemistry
    10 Atmospheric Environment
    (2.89) Journal of the Atmospheric Sciences
    (6.01) Journal of Climatology

    Strangely their names also dont appear on this list:

    Highly Cited Authors in Climate Change Research, 1999-2009
    (Ranked by total citations)

    1 F. Stuart Chapin University of Alaska Arctic Biology 57 3,365
    2 Camille Parmesan Univ. Texas, Austin Integrative Biology 7 2,794
    3 Ove Hoegh-Guldberg University of Queensland Marine Science 30 2,612
    4 Phil Jones University of East Anglia Climatic Research 39 2,480
    5 A. Townsend Peterson University of Kansas Biodiversity/Ecology 45 2,341
    6 Peter M. Cox University of Exeter Climate System Dynamics 31 2,176
    7 I. Colin Prentice University of Bristol Plant Ecology 36 2,172
    8 Terry P. Hughes James Cook University Coral Reef Ecology 10 2,144
    9 Antoine Guisan University of Lausanne Ecology/Evolution 26 2,040
    10 Mike Hulme University of East Anglia Climate Change 32 2,024
    11 Richard A. Betts Met Office/Hadley Centre Climate Impacts 25 2,000
    12 Wilfried Thuiller CNRS, Grenoble Ecology/Biostatistics 48 1,894
    13 Chris D. Thomas University of York Ecology/Evolution 28 1,884
    14 Eric Post Pennsylvania State University Ecological Dynamics 22 1,852
    15 Martin T. Sykes Lund University Physical Geography 33 1,839
    16 Gerald A. Meehl NCAR Climate and Global Dynamics 39 1,778
    17 Jeremy B.C. Jackson Univ. Calif., San Diego Oceanography 5 1,744
    18 John M. Pandolfi University of Queensland Paleoecology 5 1714
    19 Mark New University of Oxford Climate Science 14 1,711
    20 Annette Menzel Tech. University of Munich Ecoclimatology 28 1,691
    21 Myles R. Allen University of Oxford Climate Dynamics 48 1,686
    22 Andrew J. Weaver University of Victoria Earth/Ocean Science 43 1,644
    23 Peter A. Stott Met Office/Hadley Centre Climate Monitoring 46 1,614
    24 Stephen Sitch University of Leeds Earth Systems 27 1,576
    25 John F.B. Mitchell Met Office/Hadley Centre Climate Science 27 1,538

    At least the deniers have something to celebrate after the exoneration of Jones & Mann & the debunked Leakgate, Amazongate & Africa gate. Two of their right wing oil lobbyists, oops, sorry I mean “scientists” recieved awards recently…….from an EXXON funded, oil, drug & tobacco lobbyist & front group the Competitive Enterprise Institute. Wonders never cease!

    Nawww, now heres me thinking they were getting a FAIL award for saying the Hockey Stick was broken, then having Mann, Bradley & Hughes prove it wasnt.


    Ahh well guys, at least you have your own censored blogs to provide rigorous scrutiny…..of your own work, ahem.

  2. I have no doubt that this study will only serve as proof to the deniers that their champions are being prevented from publishing and that the CE scientists are all part of a “team” citing each other over and over again to drum up “alarmism”.

  3. Well done Phil M and Luke … razor sharp. When you put it so clearly, it almost has a comical ring to it! That is until one looks at what is at stake!

  4. Thanks again Phil M, your comments always improve and sometimes outdo our posts! Is there a link to a high quality version of that CSIRO talk?

  5. Is there a link to a high quality version of that CSIRO talk?

    I couldnt track it down either, so wrote to them. Hopefully they can provide some material. Will definately post it back here if they give it to me.

  6. Pingback: Climate Scientist Cleared of Altering Data - Page 3 - Reef-Geeks

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