Heat and Hostility: How Rising Temperatures May Fuel Violent Conflict

When people are already stressed, a minor insult or ambiguous action can be interpreted as a deliberate attack. Psychologists call this pattern hostile attribution bias, and it can rapidly escalate disagreements into physical confrontations. New research suggests that climate-driven stress — for example from heatwaves, droughts and storms — may be amplifying that cognitive bias and increasing the risk of violence.

Evidence linking heat to aggression

Several studies have found statistical associations between higher ambient temperatures and greater levels of violent behavior. One large South Korean study that examined assault deaths from 1991 to 2020 reported that the risk of assault deaths rose by 1.4% for every 1°C (1.8°F) increase in ambient temperature. A separate study from Finland estimated about a 1.7% increase in violent crimes per 1°C rise.

Historical perspective

Hostile attribution is not solely a modern phenomenon. Historical analysis across the Roman Empire found that many clashes clustered around drought periods. In fourth-century Britain, repeated droughts and resulting food shortages coincided with incursions at Hadrian's Wall, illustrating how environmental stress has long helped trigger conflict.

Why heat can make people more aggressive

Heat and climate extremes increase stress on individuals and communities by straining resources, reducing sleep quality, and heightening economic and emotional pressures. These stressors consume cognitive resources, making people more likely to default to a survival mindset in which ambiguous social cues are interpreted as hostile. In short, environmental strain makes hostile attributions more likely and peaceful problem solving harder.

Practical responses that reduce risk

Communities and policymakers can reduce the mental and material pressures that drive climate-related conflict. Practical measures include improved resource management, investments in mental-health and cooling services, and community agreements to share scarce resources. One example from Nepal involved municipal payments for water treatment, storage and distribution that benefitted upstream watershed villages and helped ease tensions over scarce water supplies.

While more research is needed to fully understand the mechanisms, these findings underscore two clear priorities: reduce the greenhouse-gas emissions that intensify extreme weather, and invest in local measures that lower climate stress and preserve the cognitive capacity for peaceful resolution.