Across the auto industry, a profound shift toward electric vehicles is in motion. The ultimate goal: a full fleet of zero-emissions vehicles worldwide. GM is a major player in this space and has made a serious commitment — $27 billion — toward the transformation, with the aim of introducing 30 new global electric vehicles by 2025. What must a mega-firm like GM do to transition so quickly? In this conversation, CEO Mary Barra shares her vision for the future of GM — and the auto industry — in the age of climate change.