Earth has experienced tremendous climate change, from icehouse to hothouse states and back again, over time spans of millions of years to mere decades. The geologic record preserves a vital, but incomplete, account of Earth’s climate history. Understanding this record is the primary goal of the paleoclimate research at the U-M Department of Geology and Climate & Space. The study of past climates can provide valuable insights into the climate system, its variability, and its vulnerability. In many instances, lessons learned from the past have direct implications for present and future climates. The Paleoclimate Research Group uses a variety of tools, including a hierarchy of climate models, to explore the causes and consequences of past climate change.