A new paper published published the Proceedings of the National Academy of Sciences (PNAS) re-confirmed that among scientists who actually publish peer reviewed research articles and studies on climate science more than 97% of them are convinced that Anthropogenic Climate Change (ACC) (i.e., climate change caused by human activity) is occurring.
More significantly, scientists who are convinced of ACC have generally published more climate science related papers and their research has been cited more often by other researchers than scientists who are not convinced of ACC, by a wide margin.
From the PNAS press release regarding this paper:
The paper, written by William Anderegg, James Prall, Jacob Harold and Stephen Schneider, surveyed the work of 1,372 climate researchers. They found that nearly all published climate scientists agree that human activity is driving climate change. Their findings are consistent with a 2009 survey of scientists’ attitudes as well as a 2004 survey of the scientific literature on climate change. The Anderegg et al. paper comes on the heels of a series of NAS reports that underscore the reality of human-induced climate change and the need to respond.
Furthermore among scientists who have actually published at least 20 peer reviewed articles regarding climate science, those scientists who accept Anthropogenic climate change (ACC) have published the far more peer reviewed research papers, and their research has been cited far more often by other scientists, than those climate scientists who reject ACC. In other words, the greater a scientist’s “expertise” in the field of climate science, the more likely that scientist accepts rather than rejects ACC.
From the original paper Anderegg, Prall, Harold and Schneider (which the folks at PNAS were kind enough to email me):
Because the timeline of decision-making is oftenmore rapid than scientific consensus, examining the landscape of expert opinion can greatly inform such decision-making (15, 19). Here, we examine a metric of climate-specific expertise and a metric of overall scientific prominence as two dimensions of expert credibility in two groups of researchers. We provide a broad assessment of the relative credibility of researchers convinced by the evidence (CE) of ACC and those unconvinced by the evidence (UE) of ACC. […]
We compiled a database of 1,372 climate researchers based on authorship of scientific assessment reports and membership on multisignatory statements about ACC ISI Materials and Methods). We tallied the number of climate-relevant publications authored or coauthored by each researcher (defined here as expertise) and counted the number of citations for each of the researcher’s four highest-cited papers (defined here as prominence) using Google Scholar. We then imposed an a priori criterion that a researcher must have authored a minimum of 20 climate publications to be considered a climate researcher, thus reducing the database to 908 researchers. Varying this minimum publication cutoff did not materially alter results (Materials and Methods). […]
The UE [unconvinced experts] group comprises only 2% of the top 50 climate researchers as ranked by expertise (number of climate publications), 3% of researchers of the top 100, and 2.5% of the top 200, excluding researchers present in both groups (Materials and Methods). This result closely agrees with expert surveys, indicating that ≈97% of self-identified actively publishing climate scientists agree with the tenets of ACC (2). […]
In layman’s terms, the group of scientists who are considered “experts” in the field (based on having published at least 20 peer reviewed articles) who remain unconvinced that man made climate change is real is only a mere 2-3%. That is a very tiny number indeed.
All the rest, numbering between 97-98% (depending on how high they are ranked by the criteria in the study) are convinced from the data that has been compiled and the published research that human activity is the primary cause of global warming. That’s on par with the number of biologists who accept the theory of evolution.
But there is more. It seems that the Convinced Experts (CE) group vastly exceeds the Unconvinced Experts (UE) group in the number of research papers the CE group have published and the number of times those papers have been cited by other scientists:
Furthermore, researchers with fewer than 20 climate publications comprise ≈80% the UE group, as opposed to less than 10% of the CE group. This indicates that the bulk of UE [unconvinced] researchers on the most prominent multisignatory statements about climate change have not published extensively in the peer-reviewed climate literature. […]
We examined a subsample of the 50 most-published (highestexpertise) researchers from each group. Such subsampling facilitates comparison of relative expertise between groups (normalizing differences between absolute numbers). This method reveals large
differences in relative expertise between CE andUE groups (Fig. 2). Though the top-published researchers in the CE group have an average of 408 climate publications (median = 344), the top UE researchers average only 89 publications (median = 68; Mann–Whitney U test:W= 2,455; P < 10−15). Thus, this suggests that not all experts are equal, and top CE researchers have much stronger expertise in climate science than those in the top UE group.Finally, our prominence criterion provides an independent and approximate estimate of the relative scientific significance of CE and UE publications. […]
We examined the top four most-cited papers for each CE and UE researcher with 20 or more climate publications and found immense disparity in scientific prominence between CE and UE communities … CE researchers’ top papers were cited an average of 172 times, compared with 105 times for UE researchers. Because a single,
highly cited paper does not establish a highly credible reputation but might instead reflect the controversial nature of that paper (often called the single-paper effect), we also considered the average
the citation count of the second through fourth most-highly cited papers of each researcher. Results were robust when only these papers were considered (CE mean: 133; UE mean: 84; Mann–Whitney U test: W = 50,492; P < 10−6). Results were robust when all 1,372 researchers, including those with fewer than 20 climate publications, were considered (CE mean: 126; UE
mean: 59; Mann–Whitney U test: W = 3.5 × 105; P < 10−15). Number of citations is an imperfect but useful benchmark for a group’s scientific prominence (Materials and Methods), and we show here that even considering all (e.g., climate and nonclimate) publications, the UE researcher group has substantially lower prominence than the CE group.
It seems the more research you do in the field of climate change, and the more that research is respected by other scientists, the more likely you are to be convinced that ACC is real.
Now one can argue that having published more research and being cited more often by other climate change researchers in peer reviewed journals (as opposed to online blogs or The Heartland Institute) doesn’t necessarily make you more credible than the 2 to 3 % of scientists in climate science who disagree with you that human induced climate change exists.
One can make that argument, just as one can argue that almost all biologists who are convinced of evolution, or almost all physicists who are convinced that the Big Bang occurred are not necessarily more credible than the few holdouts in those sciences. However, its not likely to convince many reasonable people when they are presented with the facts.
And the facts show that the very few “climate experts” who are unconvinced of ACC publish much less research in peer reviewed scientific journals, and even among those who in the Unconvinced Expert group who published over 20 papers their research papers are not considered as important or prominent by other researchers in the field based on the lesser number of citations of their papers by others in the climate science field.
These 97% of climate change experts who are convinced that human induced climate change is real are often derided as “alarmists” and “True Believers.” These ad hominem attacks attempt to portray the years of research and study by these individuals on the issue of climate change as more a matter of religious faith or ideological fervor rather than a cold hard look at the data that overwhelming shows rising amounts of green house gases in the atmosphere caused by human activity, and no credible alternative explanations for the tremendous rise of global temperatures over the last 160 years.
Sadly, the media has fostered the idea that a great controversy exists, when in fact among those with the most expertise no one denies warming is occurring and only a very, very few “experts” claim that human activity such as carbon emissions from the burning of fossil fuels has nothing to do with that warming and the consequences it is inflicting on our world as we speak.
This public perception of a controversy which is largely generated by the inordinate media attention given to a “vocal minority of researchers and other critics [Anderegg, Prall, Harold and Schneider, 2010, PNAS] is unfortunate because it obscures the fact that knowledgeable scientists and organizations, such as the National Research Council (in a report mandated by Congress) have concluded that there is no controversy, there is only a need to start taking action to ameliorate what will be the defining problem for the 21st Century:
A strong, credible body of scientific evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems. As decision makers respond to these risks, the nation’s scientific enterprise can contribute both by continuing to improve understanding of the causes and consequences of climate change, and by improving and expanding the options available to limit the magnitude of climate change and to adapt to its impacts. To do so, the nation needs a comprehensive, integrated, and flexible climate change research enterprise that is closely linked with action oriented programs at all levels. Also needed are a comprehensive climate observing system, improved climate models and other analytical tools, investments in human capital, and better linkages between research and decision making.
In short, the problem isn’t with the science. Nor is the problem with the scientists. The problem is with the messengers in the media who have allowed “climate change skeptics, contrarians, [and] deniers” to obtain extensive media attention and “wield significant influence in the societal debate about climate change
impacts and policy” far out of proportion to their actual numbers or the credibility of their arguments. A media tied to corporate advertisers, such as BP Exxon and others who have a stake in our continued dependence on fossil fuels. Industry groups who support this conservative based disinformation campaign with large sums of money.
The blogging community is at the moment the best alternative to the traditional media who are either too lazy or too corrupt to report the true nature of their “controversy,” i.e, that it exists nowhere outside the pocketbooks of the fossil fuel corporations and in the lies and propaganda produced by their bought and paid for shills. Please feel free to reproduce this post as widely as possible so that the paper published in the PNAS can be disseminated as widely as possible.
In addition, please contact PNAS by email at pnasnews@nas.edu to obtain a .pdf copy of the Anderegg, Prall, Harold and Schneider paper entitled “Expert credibility in climate change” because the American people need to know the facts about climate change and the overwhelming scientific consensus that supports the conclusion that ACC is not a myth, but a reality, based on a massive amount of scientific research conducted over the last three decades.
