On the heels of a United Nations report that warned we have until 2030 to stop climate change from raising temperatures above a key threshold, another study found that the increasing heat could also lead to a decline to mental health.
Nick Obradovich, research scientist at the MIT Media Lab and co-author of the new study, warned of “catastrophic” dips in mental health for some if climate change causes the global temperature to increase by 2 degrees Celsius above pre-industrial levels.
“Our paper — when coupled with evidence that climate change may impact everyday human moods to severe outcomes like suicide — provides further evidence that exposure to heat, on average, worsens mental health outcomes,” Obradovich said, according to Inverse.
The UN report says that, at the current rate, the world will witness a 1.5 degrees Celsius increase above pre-industrial levels sometime between 2030 and 2052.
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For the study, researchers combed through a decade’s-worth of data from US Centers for Disease Control and Prevention’s Behavioral Risk Factor Surveillance System, which had 2 million people self-assess their state of mental well-being.
That data were collected from 2002 to 2012.
Researchers say they noticed an increase of “problems with emotions” during 30-day periods that had temperatures averaging over 86 degrees Fahrenheit. Both people with low income and women were 60 percent more likely to have emotions tied to weather than those with a higher income and men, respectively, according to the study’s findings.
More specifically, the study determined that there was a 0.5 increase in mental health difficulties for people in a month that averaged over 86 degrees Fahrenheit when compared to a month with an average between 77 and 86 degrees Fahrenheit.
The study also found that a 1-degree Celsius increase over 5 years — or a 1.8-degree Fahrenheit increase — causes a 2 percent increase in mental health problems.
Other studies have found a connection between suicide rates and temperature.
Published in the journal Nature Climate Change, one study led by Stanford University economist Marshall Burke found that a 1.8-degree Fahrenheit increase in monthly average temperature causes a 0.7 percent increase in suicide rates in the U.S. and 2.1 percent increase in Mexico.
“Surprisingly,” Burke told Medical News Today, “these effects differ very little based on how rich populations are or if they are used to warm weather.”
But that’s not all: The study used climate change models to predict that anywhere between 9,000 to 40,000 suicides could be caused by climate change by the year 2050 if nothing is done to stop the rising temperatures.
And another study — looking at 17 years of data from Milwaukee, Wisconsin, on heat waves and hospital admissions — also found an increase of people coming to the hospital for “self-harm” during warmer times of the year.
Despite those findings, Obradovich concedes that even with his new study, “we can’t be sure” exactly why mood appears to be altered by weather.
“It could be via the impacts of heat on sleep, on daily mood, on physical activity rates, on heat-related illness, on cognitive performance, or any complex combination of the above,” he said, according to Inverse. “Unfortunately, these processes are so complex that we can’t easily identify precisely which mechanism is driving our results.”