We have therefore assembled an international multidisciplinary consortium with expertise in hydrology (Solovyanova); permafrost dynamics and geomorphology (Christiansen), biogeochemistry (Hodson and Yde), redox geochemistry (Thornton, Finster) and microbiology (Finster) to provide this information. It is further augmented by leading experts in regional modelling (Romanovsky, De’Ath), ecosystem change and biogeochemistry (Rysgaard, Tranter and Vincent) and isotope geochemistry (Heaton and Bennett), who add significant value as Project Partners. We will conduct an integrated field, laboratory and modelling study of sites from relatively warm Svalbard in Norway, eastwards into colder Siberia, covering the entire Arctic permafrost gradient. We will construct "field observatories" in important thaw environments, including yedoma terraces, ice wedge polygons, raised marine wetlands and deltas. In each case we will collect cores for laboratory studies and conduct field monitoring to construct mass balance models that describe their integrated GHG forcing potential. Laboratory studies will determine (i) how biogeochemical and microbiological conditions change with depth, from the active layer into the permafrost, and (iii) how changing temperature and moisture regimes influence the microbial communities and their functional potential for C and nutrient processing at these depths. In this way we will quantitatively link the biogeochemical conditions to the physical and functional differences between the permafrost types, establishing their potential for microbially-mediated GHG production and nutrient export to marine ecosystems. The potential impact of nutrient and organic matter export from lowland permafrost on marine ecosystem production will then be estimated by amending incubations of sea water with runoff from the different field observatories. Two workshops will provide crucial fora for establishing the integration of permafrost GHG feedbacks into the next generation of regional biogeophysical models, while also allowing our scientific contribution and its wider societal importance to be showcased. We will also establish the field observatories as innovative learning resources for future students visiting the Arctic university of Svalbard.