Jud seeks to understand how externally-forced and internally-driven changes affect the earth's climate. He uses paleoclimate archives to help evaluate both current climate trends and climate models, which are used to project future changes. Jud focuses on producing long records of hydroclimate using speleothems, corals, and forams from the tropics as well as quantifying the uncertainty of climate reconstructions and then comparing the paleoclimate data to climate model output.