Focuses on the cycling of elements at the global scale with a particular emphasis on human modification of biogeochemical cycles. Major biogeochemical cycles,their past dynamics, present changes, and potential future scenarios will be addressed. Ecosystem to global-scale model of the earth system will be discussed along with global scale measurements of element fluxes from satellites, aircraft, and measurement networks. Prereq., general chemistry, some organic chemistry. Same as ENVS 5840. Prerequisites: Restricted to Graduate Students only.