Decades of Solar-driven geomagnetic disturbances impact homicide rates in Europe and the USA

Background: Homicides are the leading cause of death among young males. Conventional approaches to interpreting variations in criminality over time and across countries have failed to explain it. Methods: We applied ordinary least squared regressions on yearly homicide rates to identify the planetary drivers for homicides in Germany, the UK, and the USA over the past three solar cycles (22 to 24) between 1987 and 2018. We used the number of sunspots (solar activity), Kp and Ap indices (geomagnetic activity) from the National Oceanic and Atmospheric Administration (NOAA) and the German Research Centre for Geosciences DFZ-Potsdam, and weather variables from the countries’ meteorological organizations. Results: Our study revealed that lagged Kp NOAA index as a parameter of solar-driven geomagnetic disturbances (GMD) was the most important predictor to explain homicide rates in all three countries. Our results showed that over half the variance in homicide rates of all three countries could be attributed to GMD, not so by weather variables. We also predicted homicide rates peaking for 2025 and 2026 during the current 25th solar cycle, suggesting the current solar cycle could prove to be one of the most intense in a century, which would signal a concomitant increase in homicide rates. Based on the Italian experience in curbing homicides, we also suggest that collective agency may break what appears to be a deadly association between GMD and homicides. Conclusions: Our study suggests GMD may be involved in shaping human behavior and may help public and medical authorities prepare for eventual surges in homicides as the 25th solar cycle may induce stronger GMD.