A systematic review of the association between climate change and suicidality reveals that climate indicators increase suicide rates.

Climate change is increasingly recognized as a public health challenge, with emerging evidence linking climate-related factors to suicidality. A search was conducted in PubMed, Scopus, PsycINFO, Web of Science and Google Scholar following the PRISMA guidelines. The studies that assessed the association between climate indicators and suicidality were included, and risk of bias was assessed using MMAT and ROBINS-E. A total of 43 studies met the inclusion criteria, covering various geographic regions and populations. Rising ambient temperatures were the climate variable most frequently studied, with multiple studies showing a significant increase in suicide rates linked to higher temperatures, particularly during the summer months, especially among females. Seasonal variations, including heatwaves and extreme cold, were associated with increased suicidality. Additionally, extreme weather events such as floods, droughts and storms correlated with higher suicide risks, particularly in vulnerable populations, including older adults and individuals with pre-existing mental health conditions. Air pollution, particularly exposure to PM2.5, NO2 and SO2, was also found to contribute to suicidality. Most of the studies originated in high-income countries, highlighting a gap in research from low- and middle-income countries (LAMICs), where the impacts of climate change may be more severe but remain understudied. Although two studies examined suicidal ideation, the overwhelming majority of the evidence focused on suicide mortality, underscoring the marked under-representation of non-fatal suicidality outcomes in the existing literature. The findings suggest that climate change plays an important role in suicidality, with increasing temperatures, extreme weather and air pollution acting as key risk factors. As climate stressors grow, it is crucial to integrate them into mental health and suicide-prevention policies. More research, especially in underrepresented regions, is needed to guide effective interventions.