Paleoclimate scientists attempt to understand fundamental aspects of the Earth's Climate System by using natural recorders of past climate change together with climate models to identify regional, hemispheric or inter-hemispheric climate patterns, and to provide the baseline for ongoing and future climate change. These disciplines use marine and terrestrial climate archives (including ocean and lake sediments, fossil corals, speleothems, ice cores, terrestrial sediments, tree rings etc) to create a record of climate changes and variabilities ranging from sub-annual timescales to millions of years. Research interests within the department include reconstructing changes in ocean chemistry and circulation, changes in the carbon cycle, in temperature and precipitation patterns, sea-level and global ice volume, atmospheric circulation and aerosol changes, mountain glacier fluctuations and changes in land-ocean interactions. We use biological, chemical, mineralogic, and isotopic measurements together with climate models to develop a global scale perspective on our climate system. The Paleoclimate faculty includes Columbia University geologists, biologists, geochemists, atmospheric scientists as well as scientists at the NASA Goddard Institute for Space Studies and the American Museum of Natural History.