The Fertile Crescent is a quarter-moon-shaped zone of relatively moist and fertile land that includes what are today large parts of Iraq and Syria.
Syria’s ongoing internal conflict began in 2011, following three years of the most severe drought recorded in the region, scientists said.
To investigate the drought’s causes, Colin P. Kelley of the University of California, Santa Barbara and colleagues examined century-long trends in precipitation, temperature, and sea-level air pressure in the region.