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Naomi Oreskes & her study: errata

Benny Peiser has his own updated web page with evidence that Naomi Oreskes' paper is not right. See also: Less than 1/2 of the published papers support global warming theory.

Also, Avery and Singer collected names of 500 scientists who have published papers whose content contradicts some aspects of the recent warming alarm. Sen James Inhofe has a similar list of 400+ scientists. A petition against the AGW orthodoxy was recently signed by 30,000 U.S. scientists.

Some of you may remember a paper by Naomi Oreskes in Science that claimed that 100% of the papers about global climate support the "consensus view". Well, Prof. Beiser obtained different results. And I won't try to tell you what conclusions you should make.

Since Naomi Oreskes has published her article, there have been dozens of new peer-reviewed "denier" articles about the climate. Try 10+ examples under this link where most articles are about the climate... Moreover, Madhav L. Khandekar has collected and nicely organized 60+ recent peer-reviewed articles against the global warming orthodoxy

From: Prof. Benny Peiser, Liverpool John Moores University

On December 3rd, only days before the start of the 10th Conference of Parties of the United Nations Framework Convention on Climate Change (COP-10), Science Magazine published the results of a study by Naomi Oreskes (1): For the first time, empirical evidence was presented that appeared to show an unanimous, scientific consensus on the anthropogenic causes of recent global warming.

Oreskes claims to have analysed 928 abstracts she found listed on the ISI database using the keywords "climate change". However, a search on the ISI database using the keywords "climate change" for the years 1993 - 2003 reveals that almost 12,000 papers were published during the decade in question (2). What happened to the countless research papers that show that global temperatures were similar or even higher during the Holocene Climate Optimum and the Medieval Warm Period when atmospheric CO2 levels were much lower than today; that solar variability is a key driver of recent climate change, and that climate modeling is highly uncertain?

These objections were put to Oreskes by science writer David Appell. On 15 December 2004, she admitted that there was indeed a serious mistake in her Science essay. According to Oreskes, her study was not based on the keywords "climate change," but on "global climate change" (3).

Her use of three keywords instead of two reduced the list of peer reviewed publications by one order of magnitude (on the UK's ISI databank the keyword search "global climate change" comes up with 1247 documents). Since the results looked questionable, I decided to replicate the Oreskes study.

Comment: 1247 is higher than 928 because Prof Peiser has included some documents in his ensemble that Prof Oreskes didn't consider to be "articles". This is a minor difference that didn't cause any serious disagreement and both scholars know how to work in both ways. But there are significant problems of other kinds, as shown later.


I analysed all abstracts listed on the ISI databank for 1993 to 2003 using the same keywords ("global climate change") as the Oreskes study. Of the 1247 documents listed, only 1117 included abstracts (130 listed only titles, author(s)' details and keywords). The 1117 abstracts analysed were divided into the same six categories used by Oreskes (#1-6), plus two categories which I added (# 7, 8):

  1. explicit endorsement of the consensus position
  2. evaluation of impacts
  3. mitigation proposals
  4. methods
  5. paleoclimate analysis
  6. rejection of the consensus position.
  7. natural factors of global climate change
  8. unrelated to the question of recent global climate change


The results of my analysis contradict Oreskes' findings and essentially falsify her study:

  • Of all 1117 abstracts, only 13 (or 0.1%) explicitly endorse the 'consensus view'.
  • 322 abstracts (or 29%) implicitly accept the 'consensus view' but mainly focus on impact assessments of envisaged global climate change.
  • Less than 10% of the abstracts (89) focus on "mitigation".
  • 67 abstracts mainly focus on methodological questions.
  • 87 abstracts deal exclusively with paleo-climatological research unrelated to recent climate change.
  • 34 abstracts reject or doubt the view that human activities are the main drivers of the "the observed warming over the last 50 years".
  • UPDATE: among the 34 abstracts, a few of them were found that shouldn't have been included in the group. For one example, see Prometheus (search for Oreskes); the reader is recommended to look at the 34 abstracts whether this error of Peiser's analysis changes the qualitative conclusions
  • 44 abstracts focus on natural factors of global climate change.
  • 470 (or 42%) abstracts include the keywords "global climate change" but do not include any direct or indirect link or reference to human activities, CO2 or greenhouse gas emissions, let alone anthropogenic forcing of recent climate change.


According to Oreskes, 75% of the 928 abstracts she analysed (i.e. 695) fell into these first three categories, "either explicitly or implicitly accepting the consensus view". This claim is incorrect on two counts: My analysis shows that only 424 abstracts (or less than a third of the full data set) fall into these three categories.

It also shows that many abstracts on "evaluation of impact" and "mitigation" do not discuss which drivers are key to global climate change, instead often focusing exclusively on the possible effects of elevated CO2 levels on plant growth and vegetation. Many do not include any implicit endorsement of the 'consensus view' but simply use certain assumptions as a basis for often hypothetical impact assessments or mitigation strategies.

Quite a number of papers emphasise that natural factors play a major if not the key role in recent climate change (4). My analysis also shows that there are almost three times as many abstracts that are sceptical of the notion of anthropogenic climate change than those that explicitly endorse it (5, 6, 7).

In fact, the explicit and implicit rejection of the 'consensus view' is not restricted to individual scientists. It also includes distinguished scientific organisations such as the American Association of Petroleum Geologists:

  • "The earth's climate is constantly changing owing to natural variability in earth processes. Natural climate variability over recent geological time is greater than reasonable estimates of potential human-induced greenhouse gas changes. Because no tool is available to test the supposition of human-induced climate change and the range of natural variability is so great, there is no discernible human influence on global climate at this time." (8)

This is not to deny that there is a majority of publications that, although they do not empirically test or confirm the view of anthropogenic climate change, go along with it by applying models based on its basic assumptions. Yet, it is beyond doubt that a sound and unbiased analysis of the full ISI databank will find hundreds of papers (many of which written by the world's leading experts in the field) that have raised serious reservations and outright rejection of the concept of a "scientific consensus on climate change". The truth is, that there is no such thing!

In light of the data presented above (evidence that can be easily verified), Science should withdraw Oreskes' study and its results in order to prevent any further damage to the integrity of science.


1) N. Oreskes (2004). The scientific consensus on climate change. Science, Vol 306, Issue 5702, 1686, 3 December 2004 (

2) ISI Web of Science (


4) C. M. Ammann et al., for instance, claim to have detected evidence for "close ties between solar variations and surface climate", Journal of Atmospheric and Solar-Terrestrial Physics 65:2 (2003): 191-201. While G.C. Reid stresses: "The importance of solar variability as a factor in climate change over the last few decades may have been underestimated in recent studies." Solar forcing of global climate change since the mid-17th century. Climate Change. 37 (2): 391-405

5) H.R. Linden (1996) The evolution of an energy contrarian. Annual Review of Energy and the Environment, 21:31-67.

6) Russian scientists K. Kondratyev and C Varotsos criticise "the undoubtfully overemphasised contribution of the greenhouse effect to the global climate change". K. Kondratyev and C Varotsos (1996). Annual Review of Energy and the Environment. 21: 31-67

7) M.E. Fernau, W.J. Makofske, D.W. South (1993) Review and Impacts of climate change uncertainties. Futures 25 (8): 850-863.

8) L.C. Gerhard and B.M. Hanson (2000) AAPG Bulletin 84 (4): 466-471

The fate of this article was also described in The Telegraph.

Some additional well-known climate articles on this weblog

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snail feedback (5) :

reader Zelah said...

Awesome Lubos!

I must confess, that I was pro Kyoto not because of the science, which is clearly not conclusive, but as a way to create a World Wide debate over the future of the World.

Yes Kyoto is corrupt , and dishonest , but the reality is that the Oil companies are also corrupt and dishonest as well.

However, I had believed that there was at least 2 sides to the arguement! Now, it is obvious that there is not!

If there is Climate Change, then man made emissions has only locked onto a naturally occuring signal!

Let look at the reality today. Kyoto is essentially now a political project which survives most probably because Europe wants to use enviromental pressure to create 'Social Europe'. i.e, it was the ONLY thing that Europeans could agree on!

I do hope that the conservatives in America do not take the easy way out and think that they can become isolationists! Europe is quite capable of deceiving itself for a very long time, and with Europe's regulatory powers it can still push through Kyoto II via anti free trade enviromental regulations which will force the rest of the world to follow!!!

An amateur mathematician

reader Andrew said...

Oreskes missed a few papers...

450 Peer-Reviewed Papers Supporting Skepticism of "Man-Made" Global Warming

reader GGirton said...

I read that Benny Peiser retracted his study after it was shown that the 34 abstracts that supposedly "rejected the consensus view" did nothing of the kind.

The link on this page that points to them goes nowhere.

That is a problem with this level of work -- it is really history of science in the making, and looking at the abstracts for this purpose misuses their point.

Global warming is not the only possible effect of the increase of CO2 in the atmosphere -- and everyone DOES agree that CO2 is increasing in the atmosphere. There is also the worrying issue of acidification of the oceans and the corresponding effect on fish life. Some fisheries have already disappeared completely and others on the ropes due to overfishing. A CO2 emissions reduction is probably justified on sea life basis alone, leaving aside the fascinating topics introduced by atmospheric science and cimate.

reader Unknown said...

Ok, you just destroyed your own credibility by stating this: "In fact, the explicit and implicit rejection of the 'consensus view' is not restricted to individual scientists. It also includes distinguished scientific organisations such as the American Association of Petroleum Geologists".

What you didn't bother to mention is that the Association of Petroleum Geologists is the ONLY major scientific organization that disputes the consensus. It is NOT an EXAMPLE. And 2/3 of their members disputed their official statement. Do you think they might have a SLIGHT bias considering what they do?!?

reader Luboš Motl said...

Not so dear Dan,

you may have missed that the author of the statement you quoted is Dr Peiser, not myself.

The original paper by Oreskes was a manifestly untrue paper about the non-existence of peer-reviewed papers that disagree with the "scientific consensus".

This basic statement was disproved in many ways and Benny Peiser was among the first ones who did it. It's much easier today to show that Oreskes' statement was preposterous: see e.g. these 450 anti-consensus peer-reviewed papers.

At any rate, the people who think that the consensus determines the truth in science are shallow imbeciles who suffer from groupthink, to put it politely, and the reason why there is a consensus about the political question of climate change in the conventional academic institutions is simply that these institutions are flooded with left-wing activists, PC hacks, and professional parasites.

Petroleum geologists may have the only professional scientific organization that is actually producing money as a byproduct of their scientific work, as opposed to the consumption of the taxpayers' money which is what virtually all other organizations of this kind are professionally doing, so it shouldn't be shocking that the Petroleum Geologists are the only ones who don't institutionally endorse a socialist pseudoscience designed to increase wealth redistribution and to increasingly cripple the industrial civilization.

Face it, all the other professional organizations are contaminated with a majority of biased parasites and deluded ideologues such as yourself. This has nothing whatsoever to do with science. Instead, it has everything to do with their ideology and their selfishness.

Best wishes

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