It is widely agreed that humans must reduce their environmental impact. We propose that an improved understanding of our evolved human nature can help to improve programs and policies to address environmental problems. Combining evolutionary and social psychological approaches, we argue that environmental problems are often caused or exacerbated by five evolutionarily adaptive psychological biases: Humans (1) value personal over collective outcomes (self-interest), (2) prefer immediate over delayed rewards (shortsightedness), (3) value relative over absolute status (status), (4) copy the behaviors of others (social imitation), and (5) ignore problems that we cannot see or feel (sensing). By considering how and why these five "Stone Age" biases continue to influence modern environmental practices, although acknowledging the role of individual and cultural differences, we present novel ways that human nature can be harnessed to develop intervention strategies to lessen resource depletion, restrain wasteful consumption, curb overpopulation, and foster green choices. © 2014 The Society for the Psychological Study of Social Issues.