The Scientific Consensus on Climate Change

From: Benny Peiser
To: Science
Submitted: 4 January 2005

Address: Faculty of Science
Henry Cotton Campus
Liverpool John Moores University
15-21 Webster Street
Liverpool L3 2ET UNITED KINGDOM

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

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.

METHOD

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

RESULTS

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

Of all 1117 abstracts, only 13 (or 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".

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.

DISCUSSION:

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 Oresekes' study and its results in order to prevent any further damage to the integrity of science.

References

1. N. Oreskes (2004). The scientific consensus on climate change. Science, Vol 306, Issue 5702, 1686, 3 December 2004 (http://www.sciencemag.org/cgi/con

2. ISI Web of Science (http://www.webofscience.com/)

3. http://davidappell.com/archives/00000497.htm

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

From: science_editors@aaas.org [mailto:science_editors@aaas.org]

Sent: 04 January 2005 11:07
To: Peiser, Benny
Subject: Thank you for your WebSubmission.

Dear author:

Thank you for using Science's Web submission site.

It will take approximately one business day to process the receipt of your submission. If you are notified that one or more of your uploaded files is unreadable, you will need to return to the site to replace the unreadable files. In order to return to the site, you will need to have the following information:

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Questions about your submission may be addressed to us at science_editors@aaas.org

Sincerely,

The Editors

----------

From: Etta Kavanagh [mailto:ekavanag@aaas.org]
Sent: 18 February 2005 18:17
To: Peiser, Benny

Subject: Your Letter to the Editor of SCIENCE

 Dear Dr. Peiser,

 A couple of weeks ago, you submitted a Letter to the Editor on Naomi Oreskes' Essay "The Scientific Consensus on Climate Change. In its current form, it is too long for a Letter, but we would consider a shorter version if you are willing to edit it. It should be 500 words or less, not counting the references. A correction dealing with the mistake in the search terms ("global climate change" vs. "climate change") was published in our Jan. 14 issue.  

Best regards, 

Etta Kavanagh
Associate Letters Editor
SCIENCE

-----------

From: Peiser, Benny
Sent: 23 February 2005 14:13
To: Etta Kavanagh [ekavanag@aaas.org]

Subject: Letter to the Editor of SCIENCE

Dear Etta Kavanagh 

Please find attached my revised letter which I have shortened below the 500 words limit. I will submit the letter also in electronic form via your website.

With best regards

Benny Peiser

Liverpool John Moores University

----------

e-letter to Science Magazine
sent: 23 February 2005

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

Abstract: As requested by Associate Letters Editor Etta Kavanagh, I have revised and shortened my letter below.   

Letter Text:

Oreskes (1,2) presents empirical evidence that appears to show a unanimous, scientific consensus on the anthropogenic causes of recent global warming. Oreskes also claims that this universal agreement had not been questioned even once in the peer-reviewed literature since 1993. Her assertion has been extensively reported ever since.

I replicated her study in order to assess the accuracy of its results. All abstracts listed on the ISI databank for 1993 to 2003 using the same keywords ("global climate change") were assessed (3). The results of my analysis contradict Oreskes' findings and essentially falsify her study: Of all 1117 abstracts, only 13 (1%) explicitly endorse the 'consensus view'. However, 34 abstracts reject or question the view that human activities are the main driving force of "the observed warming over the last 50 years" (4).

Oreskes claims that "none of these papers argued [that current climate change is natural]". However, 44 papers emphasise that natural factors play a major if not the key role in recent climate change (5).

The most significant discrepancy with Oreskes' results concern abstracts that are undecided whether human activities are the dominant driving force of recent warming. My analysis shows that a significant number of abstracts reject what Oreskes calls the 'consensus view'. In fact, there are almost three times as many abstracts that are unconvinced of the notion of anthropogenic climate change than those that explicitly endorse it (6).

Even if there is disagreement about any of these papers, it is highly improbable that all 34 are ambiguous. After all, the explicit and implicit rejection is not restricted to individual scientists (7). It also includes distinguished scientific organisations such as the American Association of Petroleum Geologists, which formally rejects the view that anthropogenic factors are the main trigger of global warming:

"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).

Despite this manifest scepticism, I do not wish to deny that a majority of publications goes along with the notion of anthropogenic global warming by applying models based on its basic assumptions. It is beyond doubt, however, that an unbiased analysis of the full ISI databank, which comprises almost 12,000 abstracts, 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, there is no such thing!

In light of the data presented above, Science Magazine should withdraw Oreskes' study and its results in order to prevent any further damage to the integrity of science.

References

1. N. Oreskes (2004). The scientific consensus on climate change. Science, Vol 306, Issue 5702, 1686, 3 December 2004 (http://www.sciencemag.org/cgi/content/full/306/5702/1686)

2. N. Oreskes (2005) Correction. Science, Vol 307, Issue 5708, 355

3. ISI Web of Science, (http://www.webofscience.com/)

4. Of the 1247 documents listed, only 1117 include abstracts. The 1117 abstracts analysed were divided into the same six categories used by Oreskes, plus two categories (#7,8) which I added: 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. While 29% of the documents implicitly accept the 'consensus view', these papers mainly focus on impact assessments of envisaged 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.

5. 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.

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. M.E. Fernau at al. stress: "More and better measurements and statistical techniques are needed to detect and confirm the existence of greenhouse-gas-induced climate change, which currently cannot be distinguished from natural climate variability in the historical record. Uncertainties about the amount and rate of change of greenhouse gas emissions also make prediction of the magnitude and timing of climate change difficult", M.E. Fernau, W.J. Makofske, D.W. South (1993) Review and Impacts of climate change uncertainties. Futures 25 (8): 850-863.

7.) "Today, proponents of catastrophic anthropogenic climate change, again claiming scientific consensus, threaten to create even greater energy market distortions at large social and economic costs." H.R. Linden (1996) The evolution of an energy contrarian. Annual Review of Energy and the Environment, 21:31-67.

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

--------

From: Etta Kavanagh [mailto:ekavanag@aaas.org]
Sent: 13 April 2005 22:39
To: Peiser, Benny
Subject: Your letter to SCIENCE

Dear Dr. Peiser,

After realizing that the basic points of your letter have already been widely dispersed over the internet, we have reluctantly decided that we cannot publish your letter. We appreciate your taking the time to revise it.

Best regards,

Etta Kavanagh
Associate Letters Editor
SCIENCE

---------

From: Peiser, Benny
Sent: 14 April 2005 15:37
To: 'Etta Kavanagh'
Cc: 'dkennedy@aaas.org'

Dear Etta Kavanagh

I am extremely disenchanted to hear that you have decided against publication of my letter.

I would be grateful if you could send me evidence for your claim hat "the basic points of [my] letter have already been widely dispersed over the Internet." As far as I am aware, neither the details nor the results of my analysis have been cited anywhere. In any case, don't you feel that SCIENCE has an obligation to your readers to correct manifest errors? After all, these errors continue to be employed by activists, journalists and science organisations (as I have informed you on a number of occasions since January). 

A statement by the Royal Society from March 2005, for instance, uses Oreskes' flawed study as a key argument in the climate change debate: 

"In the journal Science in 2004, Oreskes published the results of a survey of 928 papers on climate change published in peer-reviewed journals between 1993 and 2003. She found that three-quarters of the papers either explicitly or implicitly accepted the view expressed in the IPCC 2001 report that human activities have had a major impact on climate change in the last 50 years, and none rejected it" http://www.royalsoc.ac.uk/page.asp?id=2986

Aside from the purely technical matter of Oreskes' factual errors, does SCIENCE really want to stand behind her bizarre claim of a complete scientific consensus on global warming? Are you not aware that most observers know only too well that there is absolutely *no* consensus within the scientific community about global warming science? If not, let me remind you:

A recent international survey among some 500 climatologists found that "a quarter of respondents still question whether human activity is responsible for the most recent climatic changes."

As Professors Hans von Storch and Nico Stehr have stressed:

"The public statements made by well-known German climate researchers create the impression that the scientific fundamentals of the climate problems have essentially been solved. They claim that the scientific community has already established the conditions for taking concerted action. This is a view that in fact does not correspond to the situation in the scientific community. That's because a significant number of climatologists are by no means convinced that the underlying issues have been adequately addressed. Last year, for example, a survey of climate researchers from all over the world revealed that a quarter of respondents still question whether human activity is responsible for the most recent climatic changes" (Der Spiegel, 24 January 2005; http://service.spiegel.de/cache/international/spiegel/0,1518,342376,00.html).

 Even Tony Blair has emphasised the remaining uncertainties and ongoing scientific debates among climate scientists:

"So it would be true to say the evidence [on anthropogenic global warming] is still disputed. It would be wrong to say that the evidence of danger is not clearly and persuasively advocated by a very large number of entirely independent and compelling voices. They are the majority. The majority is not always right; but they deserve to be listened to" (Tony Blair, Davos Speech, 26 January 2005;

http://www.number-10.gov.uk/output/Page7006.asp)

I very much regret your decision to reject my letter using a contrived technicality as an excuse. Obviously, your refusal leaves me no option than to publicise the results of my analysis somewhere else (results which anyone can of course verify) - but also to deplore the sad reality of your refusal to publish corrections of a fatally flawed paper.

With best regards 

Benny Peiser
Liverpool John Moores University
Faculty of Science

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Benny Peiser is a social anthropologist at Liverpool John Moores University and the editor of the Cambridge Conference Network (CCNet). His research focuses on the effects of environmental change and catastrophic events on contemporary thought and societal evolution.

Copyright 2005, OpenDemocracy

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