Martin O’Malley’s Link Between Climate Change and ISIS Isn’t Crazy At All

It’s the dog days of summer for U.S. presidential candidates, when Donald Trump is dominating the airwaves and candidates who seem to be losing their purchase at the polls are doing whatever they can to capture some attention—whether that’s taking a chainsaw to the tax code , like Rand Paul, or claiming there’s a connection between ISIS and climate change, like Martin O’Malley.

“One of the things that preceded the failure of the nation-state of Syria and the rise of ISIS was the effect of climate change and the mega-drought that affected that region, wiped out farmers, drove people to cities, created a humanitarian crisis that created the symptoms—or rather, the conditions—of extreme poverty that has led now to the rise of ISIL and this extreme violence,” the Democratic candidate told Bloomberg on Monday.

Actually, hold that thought on O’Malley. His comment was noted by the Republican opposition-research organization America Rising and promptly mocked by conservative media outlets . The Republican National Committee issued a statement ripping O’Malley, which he was probably happy to get.

But O’Malley’s comment isn’t as weird as it might initially seem. There’s an established body of work that draws a connection between drought, resource scarcity, and conflict in general. In a 2013 article for The Atlantic , William Polk, a historian and former adviser to President Kennedy, noted a possible relationship between Syria’s civil war and devastating 2006-2011 drought. “As they flocked into the cities and towns seeking work and food, the ‘economic’ or ‘climate’ refugees immediately found that they had to compete not only with one another for scarce food, water, and jobs, but also with the existing foreign refugee population,” he wrote. “Formerly prosperous farmers were lucky to get jobs as hawkers or street sweepers. And in the desperation of the times, hostilities erupted among groups that were competing just to survive.”

In addition, a paper published earlier this year in the Proceedings of the National Academy of Sciences specifically connects a severe drought across the Levant to the Syrian conflict.

(See also: Climate Scientists Warn That Global Warming Is as Threatening As Nuclear War )

The case isn’t a direct one. “Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record,” the authors write, arguing that the drought is connected to a long-term change in the climate in the Eastern Mediterranean. “For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest.” ISIS existed in different form, as the Islamic State of Iraq, prior to the outbreak of the civil war, but the collapse of the Syrian state, combined with the fecklessness of the Iraqi armed forces and government, allowed the group to expand its reach and influence, and declare a caliphate.

Of course, scientists and security consultants get nervous when the media covers studies such as this one. They worry, in particular, about the impression that wars can be reduced to a single cause. ( As one told The Guardian in May about the PNAS study, “I’ll put this in a crude way: No amount of climate change is going to cause civil violence in the state where I live (Massachusetts), or in Sweden or many other places around the world.”) Still, O’Malley did a pretty good job compressing the study’s findings into a short explanation and contextualizing it as creating the conditions for ISIS’s success, rather than drawing a direct causal link between climate change and the Islamic State.

It’s easy to see how the baldest summary of this claim— a presidential candidate says that global warming created a huge jihadist group! —comes across as silly. But the unfortunate reality is that climate change will likely produce more evidence in the years ahead of the connection between resource scarcity and war—whether it’s fodder for presidential campaigns or not.