This week alone in our changed climate: More than two dozen people have died in wildfires in Western states and more are missing. Forecasters predict life-threatening flooding from Hurricane Sally in the Gulf. And the foundations of two major Antarctic glaciers are crumbling, threatening dramatic sea level rise. Bill Gates is founder of the billion-dollar Breakthrough Energy Ventures investment fund. He tells Molly Wood that American innovation is still necessary if we’re going to meet U.N. goals of becoming carbon neutral by 2050.