Dave is interested in numerical modeling of the Earth's climate, including 3-D atmospheric and ocean dynamics, ice sheets and vegetation. He works mostly on paleoclimates, long-term ice sheet variations, and past vegetation-climate feedbacks. He has been at Penn State since 1997, when he moved from the National Center for Atmospheric Research after helping to develop the GENESIS Global Climate Model. Recently he has worked more on ice sheet models, coupling them with global and regional climate models and applying them to Antarctica.