The recent report by the United Nations Intergovernmental Panel on Climate Change documents the damage now being done by human-created greenhouse gases and global warming. In reacting to the report, we should not be concerned about protecting our planet. Nature can survive far more than what we can do to it and is totally oblivious to whether homo sapiens lives or dies in the next hundred years. Our concern should be about protecting ourselves — because we have only ourselves to protect us. Alan Lightman, Our Lonely Home in Nature. (Alan Lightman is a physicist who teaches humanities at M.I.T. His most recent book is “The Accidental Universe.”)