Stephen Vavrus of the Center for Climatic Research in Madison, WI, is among a group of scientists who contend that extreme weather—like Tuesday’s twisters in Texas—is an outgrowth of man-made climate change, aka global warming. In the attached video, Vavrus argues that we are now witnessing the immediate effects of climate change in the growing number of floods, droughts, snowstorms, heat waves and other unusual weather events. Agree or not?