Quantifying the consensus on anthropogenic global warming in the scientific literature

[AdamSmith]

• Environmental Research Letters
• Volume 8
• Number 2

Quantifying the consensus on anthropogenic global warming in the scientific literature

John Cook^1,2,3, Dana Nuccitelli^2,4, Sarah A Green⁵, Mark Richardson⁶, Bärbel Winkler², Rob Painting², Robert Way⁷, Peter Jacobs⁸ and Andrew Skuce^2,9

John Cook et al 2013 Environ. Res. Lett. 8 024024

doi:10.1088/1748-9326/8/2/024024

© 2013 IOP Publishing Ltd

Received 18 January 2013, accepted for publication 22 April 2013

Published 15 May 2013

Abstract

We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming'. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming. In a second phase of this study, we invited authors to rate their own papers. Compared to abstract ratings, a smaller percentage of self-rated papers expressed no position on AGW (35.5%). Among self-rated papers expressing a position on AGW, 97.2% endorsed the consensus. For both abstract ratings and authors' self-ratings, the percentage of endorsements among papers expressing a position on AGW marginally increased over time. Our analysis indicates that the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research.

1. Introduction

An accurate perception of the degree of scientific consensus is an essential element to public support for climate policy (Ding et al 2011). Communicating the scientific consensus also increases people's acceptance that climate change (CC) is happening (Lewandowsky et al 2012). Despite numerous indicators of a consensus, there is wide public perception that climate scientists disagree over the fundamental cause of global warming (GW; Leiserowitz et al 2012, Pew 2012). In the most comprehensive analysis performed to date, we have extended the analysis of peer-reviewed climate papers in Oreskes (2004). We examined a large sample of the scientific literature on global CC, published over a 21 year period, in order to determine the level of scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW).

Surveys of climate scientists have found strong agreement (97–98%) regarding AGW amongst publishing climate experts (Doran and Zimmerman 2009, Anderegg et al 2010). Repeated surveys of scientists found that scientific agreement about AGW steadily increased from 1996 to 2009 (Bray 2010). This is reflected in the increasingly definitive statements issued by the Intergovernmental Panel on Climate Change on the attribution of recent GW (Houghton et al 1996, 2001, Solomon et al 2007).

The peer-reviewed scientific literature provides a ground-level assessment of the degree of consensus among publishing scientists. An analysis of abstracts published from 1993–2003 matching the search 'global climate change' found that none of 928 papers disagreed with the consensus position on AGW (Oreskes 2004). This is consistent with an analysis of citation networks that found a consensus on AGW forming in the early 1990s (Shwed and Bearman 2010).

Despite these independent indicators of a scientific consensus, the perception of the US public is that the scientific community still disagrees over the fundamental cause of GW. From 1997 to 2007, public opinion polls have indicated around 60% of the US public believes there is significant disagreement among scientists about whether GW was happening (Nisbet and Myers 2007). Similarly, 57% of the US public either disagreed or were unaware that scientists agree that the earth is very likely warming due to human activity (Pew 2012).

Through analysis of climate-related papers published from 1991 to 2011, this study provides the most comprehensive analysis of its kind to date in order to quantify and evaluate the level and evolution of consensus over the last two decades.

. . .

5. Conclusion

The public perception of a scientific consensus on AGW is a necessary element in public support for climate policy (Ding et al 2011). However, there is a significant gap between public perception and reality, with 57% of the US public either disagreeing or unaware that scientists overwhelmingly agree that the earth is warming due to human activity (Pew 2012).

Contributing to this 'consensus gap' are campaigns designed to confuse the public about the level of agreement among climate scientists. In 1991, Western Fuels Association conducted a $510 000 campaign whose primary goal was to 'reposition global warming as theory (not fact)'. A key strategy involved constructing the impression of active scientific debate using dissenting scientists as spokesmen (Oreskes 2010). The situation is exacerbated by media treatment of the climate issue, where the normative practice of providing opposing sides with equal attention has allowed a vocal minority to have their views amplified (Boykoff and Boykoff 2004). While there are indications that the situation has improved in the UK and USA prestige press (Boykoff 2007), the UK tabloid press showed no indication of improvement from 2000 to 2006 (Boykoff and Mansfield 2008).

The narrative presented by some dissenters is that the scientific consensus is '...on the point of collapse' (Oddie 2012) while '...the number of scientific "heretics" is growing with each passing year' (Allègre et al 2012). A systematic, comprehensive review of the literature provides quantitative evidence countering this assertion. The number of papers rejecting AGW is a minuscule proportion of the published research, with the percentage slightly decreasing over time. Among papers expressing a position on AGW, an overwhelming percentage (97.2% based on self-ratings, 97.1% based on abstract ratings) endorses the scientific consensus on AGW.

Full paper: http://iopscience.iop.org/1748-9326/8/2/024024/article

[RA1]

Not to be a nay sayer, but, nay, nay. Perhaps I will be allowed to compare this to the Alex Rodriguez "doping" situation. He is pursuing his claim of innocence in the media without ever testifying under oath. His accuser is therefore uncontradicted "under oath". Regardless of never testing positive for illegal substances there is physical proof as well as his accuser/witness's testimony.

There are a lot of theories about what our beloved Earth is doing and why but what I perceive is opinion from various but not all scientists regarding this phenomenon. I have no doubt that there is some climate change ongoing. Why is another question.

As stated elsewhere, neither I, nor anyone reading this will ever live long enough to know for sure. I am all for conserving nature and solving as many human problems as we can but the extent of participation necessary to actually do something positive is daunting. Paying Al Gore tribute is not on my list of things to do to help the planet.

Best regards,

RA1