Human-modified temperatures induce species changes: Joint attribution
- Center for Environmental Science and Policy, Stanford Institute for International Studies, Stanford University, Stanford, CA 94305-6055
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Contributed by Stephen H. Schneider, March 30, 2005
Abstract
Average global surface-air temperature is increasing. Contention exists over relative contributions by natural and anthropogenic forcings. Ecological studies attribute plant and animal changes to observed warming. Until now, temperature–species connections have not been statistically attributed directly to anthropogenic climatic change. Using modeled climatic variables and observed species data, which are independent of thermometer records and paleoclimatic proxies, we demonstrate statistically significant “joint attribution,” a two-step linkage: human activities contribute significantly to temperature changes and human-changed temperatures are associated with discernible changes in plant and animal traits. Additionally, our analyses provide independent testing of grid-box-scale temperature projections from a general circulation model (HadCM3).
Footnotes
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↵ * To whom correspondence should be addressed. E-mail: troot{at}stanford.edu.
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Author contributions: T.L.R. and S.H.S. designed research; D.PM. performed research; M.D.M. contributed new reagents/analytic tools; T.L.R., D.PM., and M.D.M. analyzed data; and T.L.R., D.PM., and S.H.S. wrote the paper.
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Abbreviations: AF, anthropogenic forcings; CF, combined forcings; GCM, general circulation model; IPCC, Intergovernmental Panel on Climate Change; NF, natural climatic forcings.
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Freely available online through the PNAS open access option.
- Copyright © 2005, The National Academy of Sciences
