Climate, aggression, and violence (CLASH): a cultural-evolutionary approach

- As a general trend, violence increases as climates become hotter.
- Climate, like other features of the physical environment, shapes cultural evolution.
- Seasonal variation can shape a culture of long-term planning and self-control.
- Long-term orientation and self-control are important inhibitors of violence.
- Other variables (e.g., pathogens) are related to climate and violence.

The CLimate, Aggression, and Self-control in Humans (CLASH) proposes that aggression and violence increase as climates become hotter and seasonal variation becomes smaller by influencing time-orientation and self-control. Emerging empirical evidence supporting the model is reviewed. Wealth, income inequality, and pathogen stress as powerful influences of these processes are also discussed. We conclude by discussing the theoretical and societal importance of climate change in shaping violence.