Association of Rising Ambient Temperatures with Increased Violence Worldwide: Systematic Review and Meta-Analysis

Climate change has significantly impacted human health worldwide, contributing to the rise of emerging infectious diseases, allergies, pollution, natural disasters, non-communicable diseases, and malnutrition. One crucial but often overlooked area where climate change has had a notable effect is upon interpersonal violence.

Following PRISMA guidelines, we searched PubMed and Epistemonikos for studies measuring the effect of temperature on violence. Inclusion criteria encompassed peer-reviewed, English-language articles reporting an association between temperature and violence. Data extraction focused on various forms of violence including homicides, assaults, sexual assaults, suicides, intimate partner violence, riots, and civil wars, and we assessed article quality using Joanna Briggs Institute criteria.

We included a total of 37 studies from 11 countries, three subcontinental regions, and two global-level analyses in this review. Of these, 46% originated from the United States. Rising ambient temperatures were significantly associated with increases in homicides (10 studies), assaults (15 studies), sexual assaults (8 studies), firearm violence (5 studies), intimate partner violence (9 studies), and suicides involving violent methods (9 studies). Conversely, no association was found between temperature and non-violent crimes. Civil wars and riots were also linked to temperature increases in all relevant studies. A meta-analysis of eight studies on violence showed that each 1°C increase in ambient temperature results in 1.64% (95% CI 1.23-2.19%) increase in violence (P<.01).

This review demonstrates a significant association between rising temperatures and increased worldwide incidents of violence and self-harm. These findings underscore the urgent need for public health strategies and interventions to mitigate the societal and health impacts of climate change-induced temperature increases.