On a panel with other young campaigners, climate activist Greta Thunberg spoke on the first day of the annual World Economic Forum in Davos, Switzerland, on January 21, 2020. She spoke about the 18 months since she started her climate strike and urged world leaders to listen to science. US President Donald Trump then gave a special address in which he announced he would join the forum’s One Trillion Trees initiative to help restore forests.  But at another panel discussion, Thunberg responded…