Editors' Summary

Climate change is already affecting ecosystems around the globe. In the United States, we are seeing forced species relocations due to temperature changes, reductions in habitat due to rising sea levels, and increasing adverse impacts of invasive species. These problems present challenges to implementation of the Endangered Species Act, particularly with regard to listing decisions and critical habitat designations. To address these issues, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service will need to take climate change and the "best available science" standard into account when examining effects on species.