“This may be the first decisive evidence that climate change will have a substantial effect on mental health in the United States and Mexico, with tragic human costs,” Hsiang said.
The study found suicide rates rise 0.7 percent in U.S. counties for each 1.8-degree increase in monthly average temperature.
“The thousands of additional suicides that are likely to occur as a result of unmitigated climate change are not just a number, they represent tragic losses for families across the country,” said lead author Marshall Burke of Stanford University.
In the U.S., suicides claim nearly 45,000 lives a year, twice the number of homicides, and they are the 10th-leading cause of death. Suicide rates in the U.S. have risen nearly 30% since 1999, according to a report in June from the Centers for Disease Control and Prevention.