We're accustomed to thinking of revolutions and wars as being caused strictly by human conflict. But a new study suggests that climate change may have played a role in causing the 2011 uprising against the regime of Syrian dictator Bashar al-Assad, by causing catastrophic crop failures and population movement that helped push Syrian society to the breaking point.
"We're not saying the drought caused the war," said Richard Seager, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory, who coauthored the study published on Monday in Proceedings of the National Academy of Sciences."We're saying that added to all the other stressors, it helped kick things over the threshold into open conflict. And a drought of that severity was made much more likely by the ongoing human-driven drying of that region."
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This isn't the first time that climate change has been cited as a major factor in a nation's collapse. Drought, possibly intensified by the clearing of forests for wood and farmland, also was a likely factor in the disappearance of a highly-developed Maya civilization in central America around 1,100 years ago, according to several studies.
But Syria might be the first modern instance of a societal collapse caused by climate woes. Seager and his colleagues found that since 1900, the Fertile Crescent - a region that includes much of Syria, Iraq and Turkey - has heated up by about 2 degrees Fahrenheit, and seen a 10 percent reduction in rainfall.
Those trends can't be attributed to natural climate variability, and match closely with models of human-influenced climate change, the researchers say.
Those environmental changes helped to magnify other long-term problems, including more than five-fold population growth in Syria since the 1950s, and misguided agricultural policies that encouraged the cultivation of water-intensive crops such as cotton.
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The disastrous drought caused agricultural production to plummet and wiped out livestock, which caused food shortages and drove up prices. Destitute, starving rural dwellers abandoned the fields and fled to the cities, which already were strained by an influx of refugees from war-torn Iraq.
Data suggests that global warming caused the decrease in precipitation, by weakening wind patterns that might have brought moisture-laden air from the Mediterranean. Additionally, the higher temperatures increased evaporation of soil moisture. The resulting one-two punch led to the longest, most severe drought in more than a half century.
Rising discontent led protesters - inspired by Arab Spring uprisings against repressive regimes elsewhere in the Middle East and North Africa - to take to the streets in early 2011. After the Assad regime responded with brutal repression, an armed conflict erupted.
Initially, rebel forces seized control of large swaths of the country, but by 2013, the war began to shift in favor of the better-armed and better organized Assad forces. The chaos allowed a third force, the terrorist group ISIS, to grab extensive territory and spread into Iraq.