UN Secretary General Antonio Guterres says humankind is “waging a war on nature.” Guterres spoke with CBS This Morning co-host Tony Dokopuil about the fight against climate change ahead of a major address that he’s calling “The State of the Planet.” He explains why he's made climate change a priority, the UN's objective for 2021 and the significance of President-elect Joe Biden announcing the U.S. will rejoin the Paris Climate Accord.