Is there a case against human caused global warming in the peer-reviewed literature? Part 1

Science progresses through the peer-reviewed literature; unless an idea, theory, or interpretation is reported in a peer-reviewed journal, it is just someone’s unsubstantiated opinion. Publication in a peer-reviewed journal does not ensure that an author’s arguments will stand the test of time, but rather that they have been scrutinized by experts and judged to represent a contribution to science that others in the field can benefit from knowing about.

Climate skeptics give the impression that there is a substantial case against human-caused global warming. But is it true? One way to shed light on the question is to review the peer-reviewed literature, as Naomi Oreskes did in her classic article [Science 306, p. 1686, 2004; see] She searched papers written between 1993 and 2003 for the keywords “global climate change.” She turned up 928 papers, read each abstract, and judged that none “reject[ed] the consensus position” that humans are causing global warming. 

Instead of starting with the literature, I began with a list of over 100 skeptics who have or give the impression they have scientific expertise. For example, Christopher Monckton, despite his lack of scientific credentials, gives talks in which he takes on the guise of a scientist. Anthony Watts, a former TV meteorologist, blogs about complicated scientific matters. George Will, in contrast, while acting as though he knows more than scientists, does not pretend to be one. I include Monckton and Watts, but not Will. 

I searched the Web of Science (WoS), which covers more than 8,000 peer-reviewed journals, for each skeptic by name, being careful to include variations in the spelling of the first name. I counted only primary articles; no book reviews, review articles, comments, replies to previously published papers, speeches, presentations, conference summaries, etc. I searched for articles classified by the WoS as “Meteorology Atmospheric Sciences.”

I read the abstract and sometimes the conclusions of each article. If an article takes a negative or explicitly doubtful position on human-caused global warming, I included it. I did not include papers that propose some improvement in methodology but go no further.

Admittedly, my list is subjective. I wanted to count papers that a reasonable person might conclude undercut human-caused global warming, erring on the side of inclusion. I will be happy to consider any skeptic, paper, or correction that readers suggest. This is a work in progress.

Some examples may help:

Because it appeared to cast doubt on the premises of human-caused global warming and the work of the IPCC, I counted a paper by R. A. Pielke, Sr. (2002) which concluded, “Unless it can be shown that land cover change and biogeochemical effects on the regional and global climate systems are insignificant relative to the radiative effect of a doubling of CO2, the IPCC and U.S. National Assessment reports are, therefore, summaries of sensitivity only.”

I counted a paper by Curry (2011) whose abstract reads in its entirety,"This paper argues that the IPCC has oversimplified the issue of uncertainty in its Assessment Reports, which can lead to misleading overconfidence. A concerted effort by the IPCC is needed to identify better ways of framing the climate change problem, explore and characterize uncertainty, reason about uncertainty in the context of evidence-based logical hierarchies, and eliminate bias from the consensus building process itself." Her claim that bias colors our understanding appeared to me to be an attempt to call human-caused global warming into question. 

I did not count a paper by Klotzbach et al. (2009) titled, “An alternative explanation for differential temperature trends at the surface and in the lower troposphere,” which concluded, “The differences between trends observed in the surface and lower-tropospheric satellite data sets are statistically significant in most comparisons, with much greater differences over land areas than over ocean areas. These findings strongly suggest that there remain important inconsistencies between surface and satellite records.” This paper suggests we have a way to go in our understanding of surface and satellite temperatures, but does not go so far as to imply that once we have that understanding, human-caused global warming will be called into question.

I did not count a paper by Fall et al. (2011) titled, "Analysis of the impacts of station exposure on the US Historical Climatology Network temperatures and temperature trends," whose abstract concluded, "Comparison of observed temperatures with NARR shows that the most poorly sited stations are warmer compared to NARR than are other stations, and a major portion of this bias is associated with the siting classification rather than the geographical distribution of stations. According to the best-sited stations, the diurnal temperature range in the lower 48 states has no century-scale trend." This paper did not seem to cross the line to suggest explicitly that poor station siting might have given the false impression that global warming is real.  

The results are shown on

To use the database, click on a name to bring up a list of that skeptic’s publications arranged chronologically. By hovering the cursor over the link, you can read an excerpt from the abstract or in some cases the entire abstract. Click on the link and you will be taken to the article itself or to the abstract, if there is one.

Note that some skeptics tend to publish with others: Baliunas with Soon; Balling with the Idsos; etc. So the total number of papers is somewhat less than the total obtained from adding the numbers for each skeptic. 

The point of this exercise is not just the number of papers, but what they say and whether they make a case against human-caused global warming. In subsequent posts, I will offer what I regard as the "takeaways" from these papers. 

Note: Several skeptics have published in Energy & Environment. The WoS includes only some of these papers, perhaps because somewhere along the line, the journal changed its review practices. I include any papers from E&E that come up in the WoS.

Posted by Jim Powell on Thursday, 3 November, 2011

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