Space.com #Global Warming – Natural vs. Manmade Causes Compared By NASA | Video 7 November 2016 fborgosano Leave a comment Share: When you compare possible natural causes (orbital, solar and volcanic activity) over the course of the last 100+ years, to manmade causes (aerosols, deforestation and greenhouses gases), the winner is clear. from Space.com ift.tt/2fswdgH Share: