The research paper "Extinction Risk from Climate Change" published in the journal Nature in January 2004 created front-page headlines around the world. The notion that climate change could drive more than a million species to extinction captured both the popular imagination and the attention of policy-makers, and provoked an unprecedented round of scientific critique.

Saving a Million Species reconsiders the central question of that paper: How many species may perish as a result of climate change and associated threats? Leaders from a range of disciplines synthesize the literature, refine the original estimates, and elaborate the conservation and policy implications.

Lee Hannah is Senior Researcher in Climate Change Biology at Conservation International and adjunct professor in the Bren School of Environmental Science and Management at the University of California, Santa Barbara.