A new documentary series follows teenage environmentalist Greta Thunberg's journey around the world as she witnesses firsthand the effects of climate change. CBS News' Adriana Diaz spoke to Thunberg about being a leader in the climate movement and how the lessons we've learned fighting the pandemic can help us battle climate change. The three-part documentary series, "Greta Thunberg: A Year to Change the World," premieres April 22nd on PBS.