Humans have grown accustomed to the current climate, says Stephen Vavrus, a Senior Scientist with the Center for Climatic Research in Madison, Wisconsin. But the earth’s delicate climate balance is now undergoing a radical, man-made transformation, and the changes will disrupt much in our world. 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 going on around the world. According to Vavrus, scientists are convinced that extreme weather will continue to increase as climate change gets worse.

—Kevin Gosztola