In the field of paleoclimatology, our overarching objective is to use the geologic record to understand how Earth’s climate system operates. Paleoceanography may focus on the role of the oceans in past climates, or on the history of related ocean dynamics such as biogeochemical cycles. Paleoclimatology and paleoceanography are important because instrumental records are short, and exist within narrow bounds compared to what the planet has experienced over geologic history. Past climate behavior under different conditions, such as higher greenhouse gases, changes in Earth’s orbit, or different rates of climate change, can also provide perspectives on future changes. Our faculty members use a range of geologic archives to study past climates, including ice, lake sediments, ocean sediments, paleosols, and geomorphologic features. We have particular strengths in geochronology and in applying geochemical ‘proxies’ of past climate, including isotopic tracers, trace element abundances, and organic biomarkers.