Most-Cited Authors on Climate Science

New: 2010-06-21 Just out at PNAS, my article with Bill Anderegg, Jacob Harold and Stephen Schneider entitled "Expert Credibility in Climate Change." DOI 10.1073/pnas.1003187107. My list sources page describes and links to all the sources used in compiling the list of authors covered in the paper. NOTE: on my website below I have many more names than just those that were used in the paper, including those who have not signed any statement either way, and names that I have added since the paper was written. First reactions at The Guardian, CanWest News Service via Vancouver Sun, Science Magazine, Scientific American, Union of Concerned Scientists, DeSmogBlog, Climate Progress, ClimateScienceWatch.org, Jonathan Kay, National Post (excellent)
Recent mentions: Nanaimo Daily News on Al Gore's "Dirty energy, dirty weather" talk, Weather Underground, DeSmogBlog on Anti-Science Conservative politicians, Lewandowsky et al, 'Misinformation and Its Correction,' Psy.Sci.Pub.Int. Dec.2012, Weber and Stern, 'Public understanding of climate change in the U.S.,' Amer.Psychologist, 66(4) Bell, MM. An Invitation to Environmental Psychology' [Sage, 2011] Bardes, Barbara A. Public opinion: Measuring the American mind. Rowman and Littlefield, 2012.

New: 2010-05 Interactive scatterplot chart of climate authors based on the publication and citation stats for the authors listed here. Warning: Internet Explorer currently takes a long time to open this page, and mouse response lags badly on the chart. Sorry! This subset with just the top 300 in each category still loads slowly in IE, but at least responds okay once loaded. I'm looking for a fix for that; it may just be too big a data set for the Javascript engine in MSIE? The full plot is much faster in Firefox or Google Chrome (both free downloads - try one!). It seems to be fine in Safari on MacOS X.		SkepticalScience
News: 2009-11-19 I was interviewed about this website on The Current on CBC Radio 1, for their segment on James Hoggan's powerful new book Climate Cover-up. Their program notes include a link to play the audio podcast [28 min. mp3 - my segment starts at 14:45 - 17:25] After me there is a 'rebuttal' segment with Lawrence Solomon. Note: My list includes all 37 people covered in Lawrence Solomon's book The Deniers. I've noted "LSDeniers" beside these 37 names. My separate page for this group is here: Solomon's The Deniers. Several people he profiles are not climate skeptics by any stretch; as I note in the page for this list, Sami Solanki and Nigel Weiss both complained about how Solomon protrayed them. I've put "(LSDeniers)" in parentheses for those I see as most ill-fitting as "deniers."	www.know-the-number.com Our Climate is Changing! Please download Flash Player.
	Compiled by Jim Prall, Toronto, Canada Views expressed on this site are my own and do not represent the position of my employer.

This site provides information on over 2400 climate scientists and authors who have signed public statement on climate change. This includes both statements calling for action to cut greenhouse gas emissions as well as ones that argue against such action.

Each name has a link to the person's web page at a university or national research lab, where one was found. I used Google Scholar to look up what each author had published on climate, and how widely cited their work is. This information lets us compare the credibility of those arguing against curbs on greenhouse emissions versus those supporting them.

The upshot of this comparison is that the climate change "skeptic" position has very few authors with any standing as climate scientists.
While there have been several public declarations challenging the basic science or the need for any response like emission reductions, including some with a large number of names, the great proportion of those signers turn out to have little or no qualifications on this topic.

I have compiled a list of homepages and some citation stats for all the authors from Working Group 1 ('wg1') of the 2007 Fourth Assessment Report ('AR4') from the Intergovernmental Panel on Climate Change (IPCC), as well as a longer list including other active climate science researchers. The longer list is far from complete, only compiled by hand, but it's a good start, anyway. I've continued accumulating names from as many sources as I can think of, including co-authors of those already listed, compilations of key documents in the literature on this subject, bibliographies of major literature reviews, etc. The list of AR4 wg1 contributing authors is drawn from Annex 2 in the AR4 wg1 report, pp. 955-968. (I have not flagged the reviewers named in Annex 3, only the 619 Contributing Authors named in Annex 2.) For each author I've linked to their homepage at a university or research institute (all but about 50 of the 619 AR4 wg1 authors have one.)
by cites - by # works on climate Table of all 619 IPCC AR4 wg 1 contributing authors
by cites - by # works on climate Table of 3000+ climate scientists and signatories of public declarations on climate (including AR4wg1, skeptics, and others; stats done on over 2300)
by cites - by # works on climate Table of authors who are fellows of a learned society (AAAS, AGU, AMS, Royal Society, Royal Meteorological Society)
by cites - by # works on climate Table of 259 Canadian climate authors (including AR4wg1, skeptics and others)
by cites - by # works on climate Table of UK climate authors (including AR4wg1, skeptics and others)
by cites - by # works on climate Table of 246 female climate authors (includes 79 AR4wg1 authors; 93 affirmative and 6 skeptic signers)
Lists of Climate Skeptics:
by cites - by # works on climate Table of 496 climate skeptics who signed any of twelve skeptics declarations, or appeared in TGGWS
by cites - by # works on climate Table of 37 authors profiled in Lawrence Solomon's The Deniers series in Canada's National Post (and follow-on book of the same name)
by cites - by # works on climate Table of 206 signers of the 2008 skeptics' 'Manhattan Declaration' identified as scientists by organizers
by cites - by # works on climate Table of 115 signers of the Cato Institute 2009 letter to Obama on climate (ran in newspaper ad)
by cites - by # works on climate Table of 40 listed authors of the 2008 'summary for policymakers' and/or the 2009 report from the so-called "Non-governmental International Panel on Climate Change"
by cites - by # works on climate Table of 17 people featured in Martin Durkin's 2007 film The Great Global Warming Swindle, plus 37 signers of a letter protesting errors in the film

WARNING these next two links are to pages with HUNDREDS of photo links, totaling over 40 MB for the larger set. Loading these over a slow link may take eons, or may exceed the memory limits of devices with small memory. Not recommended if you pay per byte, as on a wireless handheld (Crackberry, web-enabled cellphone etc.) Each photo links to the author's homepage, if known. Mouse over any photo to see their name and institutional affiliation.
Faces of most of the 619 IPCC AR4 wg 1 contributing authors
Faces of over 1300 climate authors and skeptics

Sources for positions taken by scientists: calls for action and open letters from scientists

Many groups have organized petitions, open letters or public declarations about climate change, both affirmative and contrarian/skeptic. In my lists I've annotated which authors have signed one or more of these. See my list of source documents for a complete list of the statements I've tabulated, with links to original documents which includes notes on my methods; see also my discussion on petitions and timeline of climate change policy response
Some of the key calls to action:

May, 2010 statement from 255 members of the U.S. National Academy of Sciences defending the integrity of climate science against attacks, innuendo and "McCarthy-like threats of prosecution", and restating the urgent need to "move forward immediately to address the causes of climate change, including the unrestrained burning of fossil fuels" [Tag: 'NAS10'; I have stats for 23 signers.]
March, 2010 U.S. Scientists and Economists& Call to Action, with over 2000 endorsers from all 50 states. [Tag: UCS10; I have stats for 178 signers.]
December, 2009 Statement from the UK science community signed by 1700 U.K. scientists, 67 universities and 55 other institutions, re-affirming the integrity of climate science and data sources, in response to the University of East Anglia email break-in. [Tag: 'UKsc09'; I have stats for 104 signers.] It begins:
We, members of the UK science community, have the utmost confidence in the observational evidence for global warming and the scientific basis for concluding that it is due primarily to human activities. The evidence and the science are deep and extensive. They come from decades of painstaking and meticulous research, by many thousands of scientists across the world who adhere to the highest levels of professional integrity. That research has been subject to peer review and publication, providing traceability of the evidence and support for the scientific method.
The January, 2009 Monaco Declaration on Ocean Acification signed by 155 oceanographers [Tag: Monaco09; stats done for 32 signers]. (Note that ocean acidification by elevated CO2 entering the oceans from the atmosphere is independent of the 'greenhouse' effect, and represents an additional harmful impact on top of temperature changes. Here's another powerful statement on how serious this 'other CO2 problem' is.)
The "Bali Climate Declaration" signed by 212 scientists in December 2007, urging the delegates to the Bali climate negotiations to negotiate strong targets for greenhouse gas reductions. [Tag: 'Bali07'; stats done for all signers.]
An open letter entitled The State of Climate Science: October 2003 from just over 1000 U.S. scientists, 880 of them PhDs. [Tag: SCS03; stats done for 94 signers.]

Other resources

A list of over sixty scholarly journals in the field of climate science and related disciplines. Each one is a link to the journal's online edition. Most allow free access to article abstracts, and some to even more content. See what peer-reviewed content on climate is available online to judge for yourself.
A list of 75 University research centers on climate-related topics.
My Blogspot site Green Herring
A 2009-09-03 NYT editorial 'Another Astroturf Campaign' about oil industry tactics in opposing U.S. climate legislation

The 'Who'

I'm not an academic, but I appreciate science and I consider myself "scientifically literate." I minored in math at CWRU (B.A., political science & philosophy, 1980). I read Scientific American basically cover-to-cover from high school until around the time the internet started to take off. Now I get my science fix online.

Thanks to my job as computer support staff at University of Toronto, I have access to electronic and/or print copies of most major journals, and a very extensive library collection of print works. I also get the opportunity to enroll in or to audit whatever courses catch my interest. I usually select one course per semester. Even when I'm just auditing, I try to do all the assigned readings. In this way I've benefited from courses on global climate change, climatology, future energy supply and demand, the physics of the greenhouse effect and planetary radiation balance, and climate politics and policy options. I also take advantage of many excellent guest lecture series, particularly those hosted by the Centre for Global Change Science in the Physics department, just across St. George St. from my office.

The 'Why'

I've been studying climatology and the science behind global warming in my spare time for several years now. Through my studies, I've come to recognize the names of the top authors and research institutes. Through following this issue online and in the media, I've also grown all too familiar with the tiny minority of 'climate skeptics' or 'deniers' who try to minimize the problem, absolve humans of any major impact, or suggest there is no need to take any action.

I've gotten pretty fed up with the undue weight given to the skeptics in the media and online. Many media reports aimed for a false 'balance' by interviewing one mainstream scientist followed by one 'skeptic.' On the web, it's even crazier, with numerous sites promoting "climate denial" by collecting names of skeptics, "quote-mining" for skeptical or ambiguous statements, and producing dodgy climate-denial 'petitions' claiming numerous "scientists" as signatories. Most of these skeptics/deniers/petition signers have little to no academic credentials in this specific field, although a handful stand out as widely published in this or a somewhat related field.

The 'What'

To put all this in context, I decided to collect all the names I could find of authors who have published on this subject, use the wonderful Google Scholar site to find their top most cited works, and gather the number of citatation for their top few papers (I settled on the top four, and I've sorted on the #4 most cited. This limits the 'one big paper' effect, but conversely underrates James Hansen down at #24, while his top cited paper would put him at #2, and his #2 paper would land 3rd. Oh well.) Overall, the citation counts from Google Scholar are most useful as a relative measure - they can either over-count or under-count both works and citations due to many variables. There's a whole body of literature on how useful or not citation counts can be for gauging authors' or journals' impact; I'm not going to tackle that here. Consider all these stats as FWIW - for what it's worth; still, they do make clear who is getting published and cited, and who much less so (or not at all).

This is my shot at 'portrait of a consensus' in the journals. I offer this as a complement to work like Naomi Oereskes' review.

The 'How'

I began with the names that came right to mind: Hansen, Wigley, Trenberth, Emmanuel; names of some pioneers like Keeling, Suess & Revelle; authors of books I've read, such as Andrew Dessler, or covered in books I enjoyed, such as Lonnie Thompson and Ellen Moseley-Thompson (described in Mark Bowen's excellent Thin Ice). Starting with these first names, I searched in Google Scholar with "author:f-lastname" or fm-lastname (equivalent to going into the advanced search page and entering the author's name). Looking at the top few results, I confirmed that I was getting papers on climate science, not false positives for someone with a similar name in some other field. Then for the top 4 valid hits, I recorded the cite counts, then also noted down all the co-authors' names. This can be quite a long list, particularly for major works such as review articles, the IPCC reports themselves, etc. Then I would just feed these names into the hopper and repeat.

For each author, I look up their current or last institutional affiliation, jotting down a few words to note their areas of research, and linking to their homepage if I can. University professors almost always have one (or more), but scholars working at a government or military research institution (UK Met Office, US Navy NRL) generally do not. In several such cases I've settled for a link to their staff directory listing, which confirms they work there and gives contact info. My notes on areas of interest are sketchy at best; for better info see the author's homepage.

I've created a reference list including name, year of Ph.D. if shown, citation stats (still gathering), homepage, and photo URL. I collect this in Excel for ease of editing, then I export as tab-delimited text and run the data through a perl script to generate various HTML files.

your home

The Results

I've packaged the same info into several different HTML presentations:

A table showing names, stats, and links to homepage, photo, and a pre-formatted query for Google Scholar to retrieve that author's publications. Google Scholar sorts results by citation count, so the first page of results gives the author's top-cited works, and is a good way to introduce yourself to an author's work.
A similar table of only Canadian authors, including the 130 who signed the CMOS open letter in 2006.
A page of only the photos, with the most cited authors first. Each photo is a link to the author's homepage. Hover the mouse over any photo without clicking to see a 'tooltip' box showing their name and institution. The photos are all in one long "line", which will wrap to fill your browser window, then can scroll vertically. This one is mostly for fun, and to give a non-verbal impression of the 'sea of faces' speaking on the science. Self-declared 'skeptics' are flagged with red brackets (e.g. signatories of various open letters that argue against any action to cut carbon emissions.)

We can use these citation stats for comparative purposes, subject to the caveat that more common names can easily match multiple unrelated authors. Journal author names are typical given only as first initial(s) and last name; it appears that searching on a full first-and-last name may not work consistently in excluding other authors with the same first initial(s), while at the same time may under-count or miss some works actually by that author.

This mixing in of false positives can often inflate the GS tot. and/or GS PAPS tot. figures. However, when viewing the citation counts, I have taken care not to count such false positives, by skimming the title, journal name, and excerpt. In that case, I try to create a custom search string to exclude false positives caused by same-named authors, before collecting the totals. This is hard to guarantee, as I'd need to review all the hits to be really certain, which is burdensome. Instead I've usually checked the first few screens of 10 results each; if there are no more false positives in the top 30, I deem the exclusions to be good enough, and the total count be 'close enough.' In some cases a name is just so common that I gave up on isolating that author's work to get the totals; in that case I've just entered "names" to indicate there were too many false positives to get a valid total.

Table of over 2900 climate authors
Table of all 619 IPCC AR4 wg 1 contributing authors Table of 225 Canadian climate scientists (including AR4wg1 and others)

WARNING these two links are to pages with HUNDREDS of photo links on one page. Loading these over a slow link may take eons, or may exceed the memory limits of devices with small memory. Not recommended if you pay per byte, as on a wireless handheld (Crackberry etc.)
Photos of over 1100 climate scientists
Photos of IPCC AR4 wg 1 contributing authors