The research team — led by Nick Obradovich, a data scientist at the MIT Media Lab who examines climate change and human behavior — was guided by the real-life experience of a diverse group of people from 263 cities across the country. All of them took part in the Behavioral Risk Factor Surveillance System, a health survey that’s been operated by the Centers for Disease Control and Prevention since 1984.
Between 2002 and 2012, nearly 2 million participants were asked this question: “Now thinking about your mental health, which includes stress, depression, and problems with emotions, for how many days during the past 30 days was your mental health not good?”
Obradovich and his colleagues used the responses to classify people into two groups: those who reported any recent days with poor mental health, and those who didn’t.
The study authors acknowledged that this was a far cry from assessing an individual’s true psychiatric state. But conducting individual assessments of so many people was simply not feasible. On the plus side, the survey participants were randomly selected to be representative of the nation as a whole. Also, the way the question was worded allowed the researchers to identify people who were experiencing mental distress even if they hadn’t sought professional health, they wrote.
The CDC data included a location for each participant, and the researchers used it to match each person’s mental health status to the weather where he or she lived. Over the 10-year study period, they found three distinct ways that climate change was associated with worse mental health.