The overall objective of GreenFeedBack is to enhance our understanding of key processes of the terrestrial biosphere – freshwater – ocean continuum in surface-atmosphere GHG exchange, the connection between them, and the impacts from human pressures. We will primarily focus on enhancing our understanding of the GHG exchange processes, biogeochemical cycles and feedback mechanisms in high latitude terrestrial and freshwater systems, marine shelves and ocean areas and thereby advance the process-based representation of ecosystems in Earth System Models (ESM), allowing for more certain climate change projections from which climate mitigation and adaptation strategies can be evaluated.