Forbes: Its not easy to get the worlds major automakers to agree on anything. But even before last weekends landmark climate change agreement by world leaders in Paris, 13 auto industry chief executives from the U.S., Europe and Asia had pledged to accelerate the development of cleaner vehicles to reduce harmful greenhouse gas emissions. The CEOs of General Motors, Ford Motor, Fiat Chrysler Automobiles, Nissan-Renault Alliance, Volvo Group, Beijing Automotive Group and Indias Mahindra & Mahindra, along...