Alexandra, please don't fall for this notion that obeying the law, in this case, the Endangered Species Act, would shut down factories or cripple the Fish and Wildlife Service. Those are right-wing talking points, and they are patently untrue.
Right now, the ESA requires an environmental review for all proposed federal projects and permits that may harm an endangered species. These reviews are done as a matter of routine, and there is a system in place for doing them. All sorts of pollutants and other environmental impacts are covered, and the law requires that these negative impacts be mitigated whenever possible in order to protect endangered species. This mechanism has been in place and served us well for decades.
Adding greenhouse gases to the long list of pollutants already studied would not shut down anything. But it would require government and industry to mitigate those emissions by using the cleanest practices and technology available. This is supposed to be our national goal, as stated by President Obama. So protecting the polar bear (and sea ice, and coastlines, etc) also save our climate and our way of life.
In other words, we have a law in place that can help us accomplish what we all know we need -- reduction in greenhouse gas emissions. And we have that law in place at a time when Congress is failing to act with a new climate change program of its own.
Why not go with what we've got, rather than embrace a Bush Administration law intended to impede action against climate change? We could use the ESA, as well as the Clean Air Act, to move forward now, instead of waiting for Congress to produce a watered down piece of legislation that likely will not go far enough anyway.