Global warming will raise suicide rates

The consequences of our actions are more far-reaching than we imagine. Consider the microbial world—the world we all actually inhabit. In his book, I Contain Multitudes, science writer Ed Yong points our mistake in loading up on both antibiotics and probiotics without a full (and personalized) understanding of our microbiome. Eradicating bacteria can be as dangerous as drowning in what we believe to be beneficial microbes.

That’s because beneficial bacteria can destroy microbes we actually need. In the coming years, doctors will offer targeted bacterial solutions to a range of diseases—one promising treatment is fecal microbiota treatment—but right now we’re hastily consuming potentially harmful bacteria while uttering the holistic medical mantra, “more is better.”

We don’t need more, we need balance. As goes our stomachs, so goes the earth. Last week I reported on Americans being unprepared to face health risks associated with climate change, including increased domestic abuse cases, contaminated drinking water, and doctors being unable to treat those in need. No sooner was that story published that my editor emailed me a study about another consequence: an uptick in suicides.

In 2013, a report speculated on the ways global warming will increase violence in regions fighting for resources. The heat does strange things to animal psychology. Spike Lee’s Summer of Sam begins with the narrator discussing the oppressive heat during the season David Berkowitz committed serial murders—the same summer as the infamous New York City blackout.

Piqued by this potential connection between heat and self-violence, the Stanford researchers, publishing in Nature Climate Change, found a linear correlation between temperature increase and suicide. After controlling for gun ownership, income level, and access to air conditioning, they discovered that suicides are in fact more common as the world heats up.

Besides scouring through suicide data back to 1968, lead author Dr. Marshall Burke, an assistant professor of earth system science, and his team analyzed over 622 million tweets over a fourteen-month period in the United States to investigate the link between rising temperatures and mental health.  

After looking at how often the location-tagged tweets used depressive language as well as the temperature of the areas tweeted from, the scientists found “a pattern that’s strikingly similar” to the suicide data, Burke says: Higher temperatures meant worse mental health.

Suicide rates have long been linked to economic tragedies. For example, last year a study found that rising temperatures increased suicides among farmers in India. The reason proffered was money lost due to crop damage. Over the last three decades, over 60,000 farmers took their own lives. Yet the Stanford study deepens our understanding of how weather affects our psychology. It might not just be the money. 

The researchers note that wellbeing decreases as temperatures increase, according to their Twitter analysis. As temperatures rise our body cools itself, changing how blood flows to our brain. Thermoregulation might increase depressive symptoms in certain individuals.

If this trend continues, the scientists write, by 2050 Americans and Canadians could experience an additional 9,000 to 40,000 suicides specific to climate change. While there are many reasons climate causes death, the researchers are confident in asserting hotter temperatures means more suicides:

In contrast to all-cause mortality, suicide increases at hot temperatures and decreases at cold temperatures; also unlike all-cause mortality, the effect of temperature on suicide has not decreased over time and does not appear to decrease with rising income or the adoption of air conditioning.

Of the many issues surrounding climate change, such as coastal flooding and increased hurricane strength, we must add suicide to the list. It might have remained “hidden” until now, but social media, despite its many ills, is a reliable indicator of our mental outlook. As temperatures rise, that outlook is looking bleak.

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