For more than 150 years, scientists have understood how greenhouse gases warm Earth’s atmosphere. With every earth system showing signs of rapid change, there is near consensus among climate scientists that human activity will change Earth’s climate for the coming millennia. But with political and industrial leaders at an impasse on how to respond to the challenge of changing climate, we must prepare to adapt to the inevitable change. Our work focuses on the Great Plains of the US, the vast grassland region west of the Mississippi River that has become the breadbasket of our country. Paleoclimatic evidence indicates that in the past 10,000 years the Great Plains has been a desert with vast areas covered in sand dunes. How often this happens, and how long these periods of drought last, is unknown. In this lecture, I will discuss using sand dune activity on the Northern Great Plains to determine the timing of periods of prolonged drought.