Considerable uncertainty surrounds projections of climate change and its ecological consequences. We surveyed 2329 environmental biologists and found that greater expertise is associated with projections of greater climatic change and more severe consequences. The opinions of scientists with greater expertise converge, and they expect larger temperature increases, higher percentages of species extinctions, and a high percentage of species' ranges will change in response to climate change over the next 100 years. Importantly, even the highest of these estimates is at the lower bounds of many published projections of climate change and threats to biodiversity. These findings suggest that experts are relatively conservative and discerning about the magnitude of climate change and its biodiversity effects, but even their conservative estimates are substantial. We suggest that policymakers consult environmental biologists on emerging and controversial issues such as climate change and use transparent, standardized metrics of expertise when deciding which scientists to consult.
Bibliographical noteFunding Information:
Funding was provided by the University of Notre Dame’s Institute for Scholarship in the Liberal Arts, College of Science, Faculty Research Program, Strategic Research Investment, and Environmental Change Initiative and by the Cedar Tree Foundation and National Science Foundation grant no. OCI1029584. DJ was supported by the Andrew W. Mellon New Directions Fellowship, and JJH was funded by the University of Notre Dame’s Institute of Advanced Study. The authors wish to thank Elizabeth Callam, Nathan Hammes, Collin McCabe, and John McMannis at Notre Dame and Kelsey Ripp, Elizabeth Ryan, and Dov F. Sax at Brown University for assistance in compiling the respondent database and members of the Managed Relocation Working Group for comments on methodology.
- climate change
- expert opinion
- scientific opinion