Exploring a paper seeing a longstanding scientific consensus on human-driven global warming


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A new paper by Skeptical Science bloggers claims to chart depth of global warming consensus since 1991. Here's my email back and forth with John Cook, Dana Nuccitelli et al.

Here's the link to the paper: http://iopscience.iop.org/1748-9326/8/2/024024/article

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Exploring a paper seeing a longstanding scientific consensus on human-driven global warming

  1. 1. New paper finding 97% AGW consensus7 messagesDana Nuccitelli Mon, May 13, 2013 at 10:48 AMReply-To: Dana NuccitelliHi Justin and Andy. You may have already received the press release about ourforthcoming paper, but I thought it might be useful to provide some moredetail. About a year and a half ago, a team of about two dozen Skeptical Sciencevolunteers began this project to quantify the consensus on human-caused globalwarming in the peer-reviewed scientific literature. Its basically an expansion on theresults of Oreskes (2004), but much larger – the most comprehensive survey of itskind. In addition to rating over 12,000 abstracts, we also contacted the authors ofthe studies we surveyed and received over 2,000 self-ratings from 1,200scientists. In both independent methods, among the papers taking a position on thecause of global warming, 97% agreed that humans are causing it. Our rejectionscategory also included papers that minimized the human influence; for example, apaper saying that most global warming has been caused by the sun fell into the 2–3% rejections category, even if it said that some warming is anthropogenic.The reason our paper is particularly important is because research has shown theresa strong correlation between public awareness of the consensus and support forclimate mitigation. However, the public is very misinformed on the issue, with theaverage American believing that scientists are split 50/50 on the cause of globalwarming. So its critical that we close this consensus gap. Thus were hoping for alot of media coverage of our paper and results.For further details, you can see my embargoed SkS blog post on the paper. Ive alsoattached embargoed copies of the paper and press release. The embargo liftsmidnight GMT Thursday (May 16th).There are a couple other interesting aspects about the paper. Were setting up asystem at SkS where anybody can go review and rate the same abstracts as in oursurvey to test our results for themselves (not active yet, but will be located here). ANew York-based marketing company, SJI Associates also created a website basedaround our results pro-bono, TheConsensusProject.com, including some really nicegraphics that can be shared via social media. If youd like to see the SJI page, theusername is secure and the password is 97percent. Everything will launch onThursday. Our paper is also open access, free for anyone to download. The fee tomake that happen was paid with donations from Skeptical Science readers (raised inunder 10 hours).Please let me know if you have any questions. Thanks.-Dana Nuccitelli
  2. 2. Skeptical ScienceThe GuardianAndrew Revkin <> Mon, May 13, 2013 at 2:20 PMTo: Dana Nuccitelli< John CookThe abstract is a bit dizzying...1) why go as far back as 1991? completely complicates the data because from then til 2001IPCC report, if you were saying humans are causing global warming you would have beenoutside the consensus?2) so 97.1 percent of 32.6 percent say warming is human caused? 66 percent take noposition.. and this means...??3) why not put this through peer review at one of the many journals, like Climatic Change,that focus on this kind of question?all of whats laid out above almost guarantees youll end up muddying waters more thanclarifying things when this comes out, unless im missing something. (happy for any clarity)[Quoted text hidden]--_Dana Nuccitelli <> Mon, May 13, 2013 at 2:54 PMReply-To: Dana Nuccitelli<John CookHi Andy. Here are some responses to your questions:1) Oreskes survey covered 1993 through 2003. We wanted to include the samedates to verify her results, and extend beyond them. I believe we chose 1991 as thestart date to make the survey encompass an even two decades, but I could be mis-remembering (John would probably know offhand).We didnt pre-define the consensus. The survey was simply about the paperspositions on the cause of global warming. As it turns out, at least 90% of paperstaking a position on the issue agreed that humans were the cause in every year1991–2011, based on our abstract ratings (there was a bit more noise in the authorself-ratings due to the smaller sample size, but I believe there was at least 80%agreement even in the early 1990s in the self-ratings). So the consensus was aresult of our survey, having already been well-established by 1991. We havea figure in our paper showing the consensus evolution over time.
  3. 3. 2) No position just means they didnt say anything about the cause of globalwarming in the abstract. In the author self-ratings, which were based on the fullpaper, nearly two-thirds did take a position, with the same 97% agreeing on thehuman cause. Oreskes in 2007 predicted that fewer papers would talk about thecause of global warming as the consensus became more widely-accepted. Theresjust no reason to continue to state something everybody accepts, especially in theabstract where words are at a premium (we discuss this in the paper).This is why we specify the 97% consensus is for papers that take a position on thecause of global warming. There are a lot of papers which investigate some aspect ofthe climate system that dont take a position on its cause, either because they feel itdoesnt need to be said or because they just didnt address the cause. We were alsovery conservative on this. For example, you could easily argue that a paperassuming continued global warming accepts the human cause, because why elsewould you expect global warming to continue? However, unless they somehowlinked the warming to human greenhouse gas emissions, we didnt rate it as anendorsement, we put it in no opinion, even if it assumed indefinitely continuedwarming.3) We chose ERL because its a high-impact journal with an open access option (Imnot sure offhand if Climatic Change has that option, but it was one of our mainconsiderations), and our paper seemed to fit within their scope.-Dana NuccitelliJohn Cook <> Mon, May 13, 2013 at 5:19 PMTo: Dana NuccitelliHi Andy, Dana, Justin,Just adding to Danas first answer. Obviously, our intent was to analyse a much largersample of papers which is why we added an extra decade to the time period of Oreskesanalysis and also included "global warming" papers (Oreskes search was just for "globalclimate change" papers). The reason we specifically started in 1991 was because the Webof Science added abstracts to their database to papers going back to 1991. At the time ofthe Oreskes 2004 analysis, the Web of Science database had abstracts only going back to1993.RegardsJohn[Quoted text hidden]Andrew Revkin > Mon, May 13, 2013 at 5:22 PMTo: John CookCc: Dana Nuccitelli
  4. 4. Still feels pretty useless (meaning the same goes for Naomis paper) given that anythingstating warming (post 1950 or...) was human caused before 2001 (TAR) did not comportwith any consensus at the time.[Quoted text hidden]John Cook <> Mon, May 13, 2013 at 5:30 PMTo: Andrew Revkin >Cc: Dana NuccitelliThe fact that the peer-reviewed literature was already showing overwhelming agreement onhuman-caused global warming demonstrates in a quantitative fashion that there *was* aconsensus prior to TAR. The IPCC didnt originate the consensus - it formalised the pre-existing consensus in a synthesising report. This is actually an important result - it showsthat the consensus wasnt manufactured by the IPCC but spontaneously emerged in thepeer-reviewed literature.[Quoted text hidden]Andrew Revkin <> Thu, May 16, 2013 at 11:30 AMTo: John Cook <>Cc: Dana Nuccitelli<still swamped and not writing on this but a final reply to johns note about thefindings showing that the consensus emerged in the literature....how do you show (in sci parlance) that the lack of mention of theAnthropogenic element in global warming in > 60 percent of papers meansthose authors all accept that AGW is evident?