The ocean and the atmosphere interact with life to set the physical and chemical conditions of Earth's surface. At Princeton, we use observations and models of varying complexity to study the climate system across multiple scales, including stratosphere-troposphere interactions, the coevolution of atmospheric carbon dioxide, ice volume and sea level, decadal to millennial oscillators in the climate system, ocean tracers as a means to understand the cycling of climatically important molecules and the importance of ocean circulation and biology in regulating climate.