Forget about giant machines to suck out carbon. If you worry about the climate, you have to save tropical rainforests. We talk with the doyen of forest activism, Frances Seymour from the World Resources Institute. But first, one of the top American climate scientists, Dr. Jonathan Overpeck on science that warns the whole world will be reclothed in unpredictable ways as the climate goes out of control. How do we know? It has happened before, when the world warmed 5 degrees Centigrade. I’m Alex, and this is Radio Climate Shock 180919