Reuters: The Iran nuclear deal and movement on climate change prompted the scientists who maintain the Doomsday Clock, a symbolic countdown to global catastrophe, to keep it unchanged on Tuesday at three minutes to midnight.
The Doomsday Clock, devised by the Chicago-based Bulletin of the Atomic Scientists, is widely recognized as an indicator of the world's vulnerability to catastrophe.
Positive developments in 2015 center on the international accord that limited Iran's nuclear program, and the agreement...