Manmade global warming helped spark the brutal civil war in Syria by doubling to tripling the odds that a crippling drought in the Fertile Crescent would occur shortly before the fighting broke out, according to a groundbreaking new study published on March 2.

The study, published in the journal Proceedings of the National Academy of Sciences, is the first to attribute the drought in Syria in large part to global warming.

In doing so, it provides powerful evidence backing up the Pentagon and intelligence community’s assessments that climate change is likely to play the role of a “threat multiplier” in coming decades, pushing countries that are already vulnerable to upheaval over the edge and into open conflict.

Previous studies had shown that the drought, along with other factors such as an influx of refugees from the Iraq War next door, helped prime Syria for conflict by 2011, when the uprising began, before transitioning into an all-out civil war. Today, once-cosmopolitan Syria has been reduced to rubble, with the terrorist group known as ISIS taking over large swaths of territory.

At least 200,000 people are estimated to have died in this conflict so far.