In entirely expected news, green groups have sued over the Interior Department’s listing of the polar bear as a threatened species — or, more accurately, over Interior’s caveats that the listing not be used as a means to fight global warming. The Center for Biological Diversity, Greenpeace, and NRDC say the bears should be listed as endangered instead of threatened, and that the listing should spell out steps to reduce climate change — the main threat to the bears’ livelihood.