Research Unit 3 is focused on the interface of the solid Earth and its atmosphere, the theatre of human activity. Links and feedbacks across this interface determine the trajectories of landscapes, ecosystems, and water at and below the surface. They also influence tectonics and climate. We explore and constrain the mechanisms operating in this coupled system, the attendant fluxes of solid and dissolved matter and trace gasses, and the characteristic response times, thresholds and teleconnections. We do this by monitoring representative terrestrial settings, mining highly resolved geological records, isolating key processes in the lab, and modeling Earth surface system dynamics. Located entirely within the GFZ, Research Unit 3 contributes to topic 3 (‘Earth Surface and Climate Interactions’) of Research Program “Geosystem: The Changing Earth”.