Why Global Warming Is a Serious Threat to Our Mental Health?

January 1, 2018

Global temperatures have already risen by about 1 degree Celsius (or 1.8 degrees Fahrenheit) since pre-industrial times and could rise another half-degree by 2030, according to a United Nations report released this week. Experts say this rise will be catastrophic for the environment, triggering changes in extreme weather, sea levels and animal populations, to name just a few of the predicted consequences.

Researchers say this continued rise in temperature has other implications for everything from the economy to the incidence of disease and famine. And it’s also been linked to an increase in mental health problems, according to a study published this week in the Proceedings of the Academy of Natural Sciences.

The study first looked at more than two million responses to an annual government survey that asked people about their mental health over the past 30 days, collected over a 12-year period. They found that people were 0.5 percentage points more likely to report problems such as stress, anxiety and depression in months when the average temperature was above 30 degrees Celsius (86 degrees Fahrenheit) than in months when the average temperature was between 25 and 30.

In other words, “when it’s really hot outside, people report more mental health problems,” said lead author Dr. Nick Obradovich, a research scientist at the MIT Media Lab.

That small increase may not seem like a lot, but Obradovich says that if you extrapolate those numbers to the entire country, it means an increase of nearly 2 million more people reporting mental health problems. And looking ahead, he and his co-authors wrote in the paper, “We observe that days with temperatures above 30 degrees Celsius are likely to become more common in the future…. Especially in the southern United States.”

Obradovich and his colleagues also looked at individual regions where average temperatures were rising. In cities that reported a 1-degree increase in average temperature over a five-year period, the researchers found that mental health problems also increased by 2 percentage points. Previous research has also suggested that higher temperatures may be linked to increases in self-harm and suicidal behavior.

The new report acknowledges that an increase in average temperature is likely just one variable that has changed over time, and that research can only show an association between temperature and mental health, not a causal relationship. But their study did control for some factors – such as the demographic makeup of the city – and the association persists.

“The finding isn’t definitive, but it certainly suggests that we should look further into this relationship,” Obradovich said. There are several possible reasons why warm weather could lead to deteriorating mental health, he added. In a previous study, he and his colleagues found that people tended to post negative emotions more frequently on social media when the temperature was highest.

“This could be a direct relationship between temperature and mood,” he said. It could also be that people have a harder time falling asleep when temperatures are higher, that temperature has an impact on cognition, or that people are simply more anxious about other consequences of climate change, he added.” Figuring out what’s really happening is one of the more important things that scientists in this field are working on.”

Living in the midst of a natural disaster can also affect mental health, and scientists say rising temperatures can mean more events, such as severe hurricanes and floods. New research has looked specifically at this angle as well. People who were directly affected by Hurricane Katrina were found to be 4 percentage points more likely to report mental health problems compared to people in other areas.

Overall, the link between warmer temperatures and mental health problems was strongest for women, people with lower incomes and those with existing mental health problems. But Obradovich said the continued rise in temperatures is something everyone should be concerned about – not just for mental health reasons.

“Climate change is a problem of everything,” he said.” It’s changing the normal environmental systems on which the well-being of our society depends. It’s an environmental issue. It’s a public health issue. It’s a national security issue. If not addressed, it poses a serious threat to humanity.”