Globally salt marshes store over 50% of the coastal carbon (termed “blue carbon”, BC) and are responsible for 25-40% of the global oceanic carbon storage. Remarkably we know very little about BC storage, greenhouse gas (GHG) emissions, habitat and biodiversity loss and ecosystem services in Nordic salt marshes under a changing climate. In NordSalt we will assess (1) changes in Nordic salt marsh habitat distribution, plant community biodiversity, (2) blue carbon (BC) sequestration, GHG emissions and coastal protection as ecosystem services as a function of plant community structure in relation to climate change and local anthropogenic and management pressures. We will combine results from regional and national analyses, case study site measurements and assessments, a long-term mesocosm warming experiment and to assess the current role of these habitats in climate related carbon dynamics as well as their vulnerability to climate change impacts. Most importantly, we will co-produce this knowledge in collaboration with stakeholders that are engaged throughout the project period – and enable the knowledge to be used post-project completion. In collaboration with practitioners and other stakeholders, we will assess the feasibility of and propose management practices for NordSalt habitats as Nature-based solutions (NbS) for climate change mitigation at different levels of governance. We will collaborate with and enable stakeholders to implement our findings into national, regional, European and global climate and habitat policy. Multi-Actor Labs will use qualitative and quantitative tools to support the co-creation exchanges between scientific experts, stakeholders, business entrepreneurs, sector- and administrative representatives. The consortium’s collective expertise, 100+ aggregate years in coastal ecology, biodiversity, climate change mitigation, dissemination and the science-policy-industry interface - providing a good platform for achieving these goals.