View of cracked earth in an area that used to be underwater in the Jaguari dam, in Vargem, 100km from Sao Paulo. during a drought affecting Sao Paulo state, on August 19, 2014. The Jaguari dam is part of the Sao Paulo's Cantareira system of dams, which supplies 45% of the metropolitan region of Sao Paulo --20 million people-- and is now at historic low.National Journal

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Before civil war engulfed Syria, the Middle Eastern nation suffered through a punishing drought.

That drought—Syria's worst in recorded history—helped create a powder keg of civil and political unrest that erupted into violent conflict during the spring of 2011. And according to a study published in the Proceedings of the National Academy of Sciences on Monday, climate change was likely a catalyst of the bone-dry conditions that played a role in the advent of the Syrian civil war.

"The severity of the drought, which was made more likely by climate change, added to other stressors, led to the unraveling of Syrian society," Richard Seager, an author of the study and a climate scientist at Columbia University's Lamont-Doherty Earth Observatory said in an interview.

As many as 1.5 million Syrians moved from the countryside to already-overcrowded cities after the drought that began in 2006 led to massive crop failures. Bashar al-Assad's government did little to aid the internally displaced people, a policy of inaction that fueled growing resentment toward the regime and set the stage for the Syrian uprising.

Journalists and political analysts alike have speculated that drought catalyzed conflict in Syria. But the research published Monday is the first major scientific study to link the parched conditions to climate change.

It is nearly impossible to pin a single extreme weather event on global warming. And researchers readily admit that they cannot prove that climate change caused Syria's drought. But the study shows that rising temperatures and less frequent rainfall spurred by rising greenhouse-gas emissions have increased the odds that droughts like the one that ravaged Syria will occur across the Middle East.

The study's conclusion adds to a growing body of scientific research linking climate change to violent conflict. A study published in Science in 2013 found that rising temperatures increased the risk of civil and political unrest around the world. The Pentagon has also warned that global warming accelerates "political instability, and social tensions—conditions that can enable terrorist activity and other forms of violence."

The drying that is occurring will also affect Lebanon, Jordan, Israel, Iraq, and Afghanistan, Seager said. "This is an area of the world likely to see more environmental stress in a place that's already conflict-prone."

This article is from the archive of our partner National Journal.

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