Climate change and crime

Dynamics

There are various theories to explain the relationship between rising temperatures and crime rates.

Temperature-aggression theory

The temperature-aggression theory, also known as the biological theory, claims higher temperatures can lead to increased levels of stress in individuals, potentially resulting in aggressive behaviors. As temperatures rise, people may become more prone to frustration and anger, which could contribute to an increase in violent crimes such as assaults and homicides. Other studies have explored this concept, examining whether heat-induced aggression correlates with higher rates of violent crime. Temperature aggression theory relies on examining historical data to identify correlations between abnormally high temperatures and increased rates of violent crimes over time. Patterns in crime data across different seasons or during specific weather events can indicate whether violent crime rates increase during hotter periods. Other variables - time of day, location, and demographics can also be influences.

Routine activity theory

The routine activity theory states that crime is more likely to occur when three conditions are met: a motivated offender, a suitable target, and a lack of capable guardianship. Warmer weather encourages outdoor activities and social interactions. This creates opportunities for motivated offenders to find suitable targets where people leave goods or property unattended. The routine activity theory does not imply that higher temperatures directly cause crime, but rather it underscores that environmental factors, affect human behavior to create conditions conducive to criminal activity.

Temperature changes

Several studies have examined the relationship between temperature and crime.

• The "climate change-temperature-crime hypothesis" across fifteen U.S. cities over a fourteen year period found that most correlations between temperature and crime were insignificant, which the researchers said suggested that other social, economic, or environmental factors might be more influential.
• One study examined the relationship between temperature and precipitation on crime in St. Louis, Missouri from 1990 to 2009, concluding that increased temperature anomalies lead to an increase in monthly crime rates. There was also correlation among violent crimes, like aggravated assaults, higher temperatures, and a shorter rainy season. Although this connection was mild, they found a stronger relationship between the temperature anomalies during El Nino/La Nina cycles and conflict.
• Another study examined annual temperatures and crime rates in the U.S., finding a correlation with specific crime types, such as assault and robbery. Others, like murder, showed no significant relationship.
• In 2021 Trujillo and Howley published a study that found higher temperatures yielded an increased in interpersonal violence, while higher humidity and precipitation were linked to decreased violence in Barranquilla, Colombia. The study supported the general aggression model and concluded that weather factors were important in urban areas.