A Trump supporter argues with a Biden supporter on the street outside Sacramento McClellan Airport as President Donald Trump was being briefed on wildfires in a hangar in McClellan Park, Sacramento, Calif., on Sept. 14, 2020.
Gabrielle Lurie—The San Francisco Chronicle/Getty Images
September 15, 2020 9:18 AM EDT

If you pick up the newspaper these days, it’s hard not to be overwhelmed by the headlines: historic wildfires, a deadly pandemic and an impending U.S. election unlike any in recent memory. When you take a step back, it seems a bit like the fabric of society is fraying. Climate change isn’t entirely responsible for any of these problems, but there is a growing body of literature suggesting that climate change shapes political and social stability.

Research has shown repeatedly that warmer temperatures and more extreme weather contribute to a slew of adverse outcomes: violent crime, political instability and the collapse of regimes, to name a few. This year is likely to be the first- or second-hottest year on record, and extreme weather and climate-related events have struck from coast to coast in the U.S., not to mention around the world, and so it’s worth asking: what role does climate change play in our current political instability?

It’s a controversial question. For years, many politicians and commentators shuddered when scientists or climate activists discussed climate change in relation to individual storms or wildfires, accusing them of politicizing disaster—and, in those cases, the link to climate change was relatively straightforward. The evidence connecting climate change and political stability has been less obvious, but is becoming increasingly impossible to ignore. Warmer temperatures and extreme weather exacerbate social stress and worsen economic outcomes; these in turn affect political behavior. A landmark 2013 paper in the journal Science found that a change in temperature of one standard deviation was associated with a 2.3% increase in interpersonal conflict rates and a 13.2% increase in the rate of intergroup conflict. By 2050, temperatures are expected to rise by two standard deviations in most places across the globe and by as much as four standard deviations in some places.

Those percentages may seem small, but in many cases they can be enough to lead to serious problems. “A lot of the way in which climate change is really bad is like death by 1,000 cuts,” says Solomon Hsiang, author of the 2013 study and director of the Global Policy Laboratory at the University of California, Berkeley. “Some of the biggest problems are situations in which we don’t realize we’re being affected by the climate, because then we don’t do anything to protect ourselves.”

The past: a history of climate change-induced political upheavals

Climate has shaped human life from the very first civilizations. A range of studies have shown how weather and climatic conditions have led to the collapse of societies, from the decline of the Tang dynasty in China in the 10th century to the decline of the Mayan civilization around 900 A.D. to the reshaping of settlement in Africa before the common era.

A prime example is the city of Angkor, the capital of the Khmer Empire in Cambodia from the 9th to 15th centuries. In its 600-year existence, the Khmer civilization built a complex system of waterways to meet Angkor’s needs as well as to protect the city from flooding. But, as a 2010 study in the journal Proceedings of the National Academy of Sciences laid out, the region was hit with a decades-long drought in the 15th century that came as global temperatures transitioned from a warm period to a cool period. At the same time, the empire faced other pressures—namely, conflict with a neighboring kingdom and economic pressure from a change in trade patterns. The combined effect was the collapse of Angkor.

It’s easy to think about ancient civilizations and chalk up their failures to naiveté. They didn’t surf the internet or zip around the world on airplanes; surely, 21st century civilizations can better adapt to climactic changes. The thing is, while we may be far more technologically advanced today, ancient civilizations didn’t spew hundreds of billions of tons of carbon dioxide into the atmosphere. The result of those emissions—created over a tiny fraction of human history—is a sharp temperature rise poised to blow the climatic changes faced by ancient civilizations out of the water. “We’re so tempted to look at the historical record and say, ‘those guys didn’t know what they were doing, but we are super sharp now,’” says Hsiang. “I’m pretty sure those guys thought the exact same thing.”

The present: a tumultuous time, politically and climatically

Today, the U.S. faces a wide range of challenges, most of which, at their core, have nothing to do with climate change: centuries of systemic racism, an ailing health care system and rampant economic inequality, to name a few. Globally, there’s a wide range of similarly vexing problems. There’s a case to be made for how climate change exacerbates these problems: urban heat islands make people of color more vulnerable to heat waves, flooding spreads water-borne diseases that stress health care systems and extreme weather hits the poorest hardest.

More subtly, extreme temperatures and weather shape human behavior, which in turn affects social and political stability. “We are creatures that live in an environment, our environment is our climate,” says Alexander Cohen, an assistant professor of political science at Clarkson University who studies climate and political behavior. “To analyze political behavior, or really any social behavior, without looking at this huge variable is to not tell the whole story.”

In these tumultuous times—both politically and climatically—there are several key factors of human behavior to consider. Research has shown that warm temperatures increase the odds of violent interpersonal interactions: cities see spikes in violent crime and police are more likely to use force in extreme heat. Studies have also found that people dealing with extreme heat are more likely to distrust outsiders. And research has shown that challenging weather shapes political decisions. “When people are uncomfortable, weather explains some of that,” says Cohen. “It can explain how they respond to public opinion surveys, we know that it affects how they vote, or if they vote at all.”

The research on these linkages is fairly nascent, and it’s hard to lay out precisely the subtle role climate is playing in our current turmoil. But, in recent weeks, hundreds of thousands have been displaced in California and Oregon, more than 10 million acres of farmland have been damaged by a storm in Iowa, and a pair of hurricanes have flooded parts of Louisiana and Texas. Temperatures across the country are on track to make this one of the hottest years on record. It’s hard to imagine this upheaval isn’t subtly feeding into the zeitgeist.

The future: what could come next if climate change is left unchecked

Climate change’s role in shaping politics and geopolitics today may be subtle, but in the future, its influence is certain to be more pronounced—and concerning. If climate change is left unchecked, bigger storms, unsurvivable heat and disappearing coastlines will leave billions displaced or struggling to survive. This would in turn create unprecedented strain on political and social institutions, not mention the global economy.

No one really knows exactly how the fallout will occur. But there’s a strong scientific basis to assume that without urgent action to stem emissions we’ll be in for many more years and decades of disturbing newspaper headlines—and they won’t be just about storms and heat waves.


A version of this article was originally published in TIME’s climate newsletter, One.Five. Click here to sign up to receive these stories early.

Write to Justin Worland at [email protected].

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