In a January NY Times Op-Ed. An excerpt:

We’re not against protecting plants and animals under the Endangered Species Act. Alaska has supported listings of other species, like the Aleutian Canada goose. The law worked as it should – under its protection the population of the geese rebounded so much that they were taken off the list of endangered and threatened species in 2001. Listing the goose – then taking it off – was based on science. The possible listing of a healthy species like the polar bear would be based on uncertain modeling of possible effects. This is simply not justified. What is justified is worldwide concern over the proven effects of climate change. The Center for Biological Diversity, which petitioned for the polar bear to be protected, wants the listing to force the government to either stop or severely limit any public or private action that produces, or even allows, the production of greenhouse gases. But the Endangered Species Act is not the correct tool to address climate change – the act itself actually prohibits any consideration of broader issues. Such limits should be adopted through an open process in which environmental issues are weighed against economic and social needs, and where scientists debate and present information that policy makers need to make the best decisions. Americans should become involved in the issue of climate change by offering suggestions for constructive action to their state governments. But listing the polar bear as threatened is the wrong way to get to the right answer.