I magine, on account of an economic downturn associated with massive defense spending, or a change in regulatory philosophy, or a pandemic, the U.S. Congress enacted legislation duly signed by the president to sell virtually all federal wild lands to the highest bidder without restriction. Would such action be constitutional?

State wildlife agencies commonly claim they are entitled to manage wildlife under the public trust doctrine (PTD). This assertion is frequently made in judicial proceedings, with state requests that their managerial authority be given due force throughout state, private, federal, and even tribal lands. One might conclude that a rich body of PTD practices and policies exists for wildlife; in reality, the PTD in state wildlife management proves to be ephemeral.

The U.S. Supreme Court’s opinion in Weyerhaeuser Co. v. U.S. Fish & Wildlife Service raises important questions about the scope of the Endangered Species Act’s (ESA’s) protections for critical habitat. Foremost among them is a question one might think was long settled: what is “habitat”? In a short ruling, the Weyerhaeuser Court opined that “critical habitat” must first be “habitat,” but it did not attempt to define exactly what habitat is or how much deference the U.S. Fish and Wildlife Service should get on what is both a biological and policy question.

This Article, adapted from Chapter 16 of What Can Animal Law Learn From Environmental Law?, 2d Edition (ELI Press, forthcoming 2020), explores existing and potential wildlife conservation policies that could play a vital role in mitigating global climate change. It describes how climate change is impacting wildlife and biodiversity around the globe and reviews the history and current state of U.S. policy, including how the federal government currently manages climate change issues under the ESA.

The Endangered Species Act defines an endangered species as one at risk of extinction “throughout all or a significant portion of its range.” The U.S. Department of the Interior (DOI) has repeatedly defined “significant portion” to mean an area of the range essential to species persistence. This definition is redundant, and various iterations of the definition have been struck down in the past. At the same time, other proposals to list a species only in a portion of its range fail to satisfy the statutory requirements.