Ira Helfand hopes Pope Francis will call for the abolition of all nuclear weapons when he addresses Congress in September and Helfand has reason for cautious optimism… The Springfield, Mass., physician is co-president of International Physicians for the Prevention of Nuclear War. It was awarded a Nobel Peace prize in 1985 “for spreading authoritative information and raising awareness of the catastrophic consequences of a nuclear war.”… It takes the work of several peer-reviewed studies done by atmospheric scientists Alan Robock of Rutgers University, Brian Toon of University of Colorado-Boulder, and Richard Turco of University of California, Los Angeles, who have found that if India and Pakistan each exchanged fifty 15 kiloton-size bombs — a tiny fraction of the size of the warheads in the U.S. and Russian arsenals — they would create immense firestorms that would quickly envelope the planet with layers of dense stratospheric smoke… Robock, a professor in the Department of Environmental Sciences, told NCR that his research reaffirmed his belief that nuclear weapons pose the “greatest and most immediate threat to humanity.”