Global climate change poses a threat to the well-being of humans and other living things through impacts on ecosystem functioning, biodiversity, capital productivity, and human health. This paper briefly surveys recent research on the economics of climate change, including theoretical insights and empirical findings that offer guidance to policy makers. Scientists estimated that, if temperatures only rose 2 C, global gross domestic product would fall 15%. If temperatures rose to 3 C, global GDP would fall 25%. If nothing is done, temperatures will rise by 4 C by 2100. Global GDP would decline by more than 30% from 2010 levels. That's worse than the Great Depression, where global trade fell 25%. The only difference is that it would be permanent.