When he began thinking about the psychological challenges presented by climate change, he was struck by how similar our coping mechanisms were to recovering drug addicts or terminally ill patients. Our addiction to a fossil fueled lifestyle and general refusal to recognize its harmful effects is similar to a junkie in denial, Johnston says. So is the process through which we come to terms with its mortal consequences, which proceeds from denial to anger, bargaining, depression, and acceptance—the stages of grief.