Evaluation of the data and models that make up our current understanding of past climates.  Emphasis will be placed on an historical introduction to the study of the past ten to few hundred thousand years, with some consideration of longer time scales.  Evidence from marine and terrestrial sediment, ice cores, corals and speleothems will be used to address the mechanisms behind natural climate variability.  Models of this variability will be evaluated in light of the data.  Topics will include: sea level and ice volume, surface temperature evolution, atmospheric composition, deep ocean circulation, tropical climate, ENSO variability and terrestrial/ocean linkages.  The class is structured as a tutorial, in which small groups of students meet individually with the instructor, and topics are presented by the students. Each student will write papers, give presentations, and lead discussions on 3 topics throughout the term. Limited to 10 students maximum. Offered 2026-27.