According to a recent article in the Huffington Post, the reason why ISIS was able to form and grow so fast was global warming (note: do not check your calendar it’s September not April fools day they really believe this).
The authors of the piece; Charles B. Strozier Professor of History, The City University of New York; and Kelly A. Berkell Attorney and research associate, Center on Terrorism at John Jay College of Criminal Justice believe that ISIS formed because of a severe drought in Syria from 2006-2010 and that drought happened because of—you guessed it—Climate Change.