Erika Gregory: The world doesn't need more nuclear weapons

Today nine nations collectively control more than 15,000 nuclear weapons, each hundreds of times more powerful than those dropped on Hiroshima and Nagasaki. We don't need more nuclear weapons; we need a new generation to face the unfinished challenge of disarmament started decades ago. Nuclear reformer Erika Gregory calls on today's rising leaders -- those born in a time without Cold War fears and duck-and-cover training -- to pursue an ambitious goal: ridding the world of nuclear weapons by 2045.