On March 2, 2015 The New York Times reported on a study published in the Proceedings of National Academy of Science that draws “evidence that the 2007−2010 drought contributed to the conflict in Syria” and concludes “that human influences on the climate system are implicated in the current Syrian conflict.”
You may read the article on The New York Times internet site.
You may download the study, “Climate change in the Fertile Crescent and implications of the recent Syrian drought” from the Proceedings of the National Academy of Science internet site.