Beginning in the 1980s, conservation groups began campaigning for the federal government to list the fluvial Arctic grayling—a relative of the salmon that lives only in the cold waters of North America—as threatened or endangered under the Endangered Species Act. In 2014, the U.S. Fish and Wildlife Service declined to list the grayling under the Act, citing, among other things, the
uncertainty associated with how the grayling would respond to climate change. The Endangered Species Act has long been heralded as one of the United States’ most protective environmental statutes, due in part to its precautionary mandate that the government take action to help species before they face extinction. But agency implementation and judicial interpretation of the
Endangered Species Act has only recently begun to grapple with the crisis of climate change, which threatens global biodiversity and promises to test the strength of the Endangered Species Act. One factor complicating traditional enforcement of the Endangered Species Act in the face of climate change is the uncertainty that can cloud species-specific climate science. This uncertainty makes it difficult for agencies to know how climate change will impact a particular species. In the face of this uncertainty, this Note argues that agencies should embrace the precautionary principle to help guide listing decisions and critical habitat designations under the Endangered Species Act.