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 and the impacts from human pressures. A nr of RIs (e.g, GIOS, ICOS, ACTRIS, PEEX) located in high latitude ecosystems will be used. Primary focus is on enhancing our understanding of the GHG exchange processes, and connections with Earth System Models (ESM). allowing for more certain climate change projections.