My primary research interests are in understanding the causes of ice ages and of rapid, millennial-scale climate changes. I also work on the stability of ice sheets. My areas of expertise include glacial geology, geomorphology, geochronology (particularly radiocarbon and uranium-thorium dating), and paleo-lake reconstruction/geochemistry. I also am involved in a project to reconstruct past marine mammal distributions in Antarctica. At present, I have research projects in the Antarctic, South America, and Greenland.