Mental health problems will increase as temperatures rise due to climate change, a new study warns.
The researchers said that over five years, a 1 degree Celsius (1.8 degree Fahrenheit) increase in average temperature is associated with higher rates of mental health issues, CNN reported.
The study was published in the journal Proceedings of the National Academy of Sciences.
"We don't exactly know why we see high temperatures or increasing temperatures produce mental health problems," lead author Nick Obradovich, a research scientist at the Massachusetts Institute of Technology's Media Lab, told CNN.
"For example, is poor sleep due to hot temperatures the thing that produces mental health problems? We have a lot of work to do to figure out precisely what is causing what," Obradovich said.
For the study, the researchers compared self-reported mental health data from nearly 2 million Americans with daily weather data from 2002 and 2012, CNN reported.
In the study, those most vulnerable to mental health problems caused by rising temperatures included people with existing mental health conditions, those with lower incomes, and women.
The findings are consistent with recent work by other scientists, Dr. Jonathon Patz, a professor and director of the Global Health Institute at the University of Wisconsin-Madision who was not involved in the study, told CNN.
He noted that people may be experiencing "stress and despair" occurring "as governments and industry fail to react at the pace recommended by multiple scientific assessments."
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Nick Obradovich el al., "Empirical evidence of mental health risks posed by climate change," PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1801528115