The Sun circles the earth! Spontaneous generation can bring forth life!  The earth is one solid mass!  These are all statements that the majority of scientists once agreed with, but that we now recognize to be incorrect.  It is easy to look back on them and feel confident about how far human knowledge has come, but the truth is that many of the statements scientists agree with today are just as likely to be proven wrong in the future.  Science is an evolving process with new ideas being developed and old ones being thrown out or improved on all the time. 

Still, despite the evolving nature of scientific knowledge, there is value to establishing the current consensus.  An understanding of where the scientific community stands on critical issues helps guide public opinion and motivate policy.  The process of producing reports that represent scientific consensus was the focus of a recent IGC seminar class.

The class first discussed the process for establishing a scientific consensus using the National academy of sciences (NAS) and the intergovernmental panel on climate change (IPCC) as case studies.  Next, they analyzed how well a recent IPCC report for policy makers was supported by citations of scientific literature.  The class was surprised by the mixed quality of citations in the document; while some citations were well-chosen and accurately portrayed in the report, others could have been improved.  For example, some supporting literature seemed a poor choice given that much better research could have been cited.  In other cases, the explanations were very carefully worded to skirt the complexities of the issue discussed in the citation.  Some statements even lacked citation all together, even though good sources were available.  The class discussed the challenges of navigating citations in this sort of document: use too many citations and the document becomes too dense to read, use too few and risk implying uncertainty and creating ammunition for skeptics.

Finally, the class discussed the importance of consensus to policy makers and the public, focusing on a paper that assessed how perceived consensus influences public perception. The research found that perceived consensus can have a strong impact on individual beliefs, but that the public consistently underestimates the consensus among scientists regarding climate change, even after being presented with information explicitly stating the level of consensus.

Although scientific consensus is not infallible, it plays an important role in informing government policy and the public perception of global issues.  Understanding how the consensus is established, and the costs and benefits associated with it, is critical being an informed student of global change.


Becca O’Brien is PhD student co-advised by Bill Hopkins and Ashley Dayer.  She is studying the social and ecological aspects of hellbender conservation.