Joint Policy Brief of NAPSEA, NORDBALT-ECOSAFE and NEW-HARMONICA

Eutrophication has emerged as one of the most persistent and widespread environmental challenges affecting aquatic ecosystems across Northwestern Europe over the past century. Driven primarily by excessive nutrient inputs—particularly nitrogen and phosphorus—from agriculture, wastewater, and industrial sources, eutrophication has severely impacted marine, coastal and freshwater systems. These nutrient overloads have led to algal blooms, oxygen depletion, biodiversity loss, and the degradation of water quality, threatening both ecological integrity and socio-economic activities such as fisheries, tourism, and drinking water supply. Despite decades of policy interventions and technological improvements, the problem remains deeply entrenched, highlighting the need for coordinated, cross-sectoral strategies that address both legacy pollution, current nutrient management and emerging pressures, including climate change. In support of its Zero Pollution Action Plan, the EU supported three projects (NAPSEA, NORDBALT-ECOSAFE and NEW-HARMONICA) with the objectives to develop and demonstrate methodologies to: Identify safe ecological boundaries for nitrogen and phosphorus and load reduction targets. Quantify sources and pathways of nitrogen and phosphorus from source to sea. Quantify the impact of climate change on these sources and pathways from source to sea. Develop more effective governance approaches. These projects differed in geographical scope and scientific approach. This policy brief summarizes the results of the three projects on the objectives above. Key messages 1. Harmonise nutrient threshold standards across Northwest Europe to unify restoration goals. 2. Invest in harmonized and enhanced nutrient and hydrological monitoring. 3. Use national Load Reduction Target (LRT) models to quantify sector-specific contributions, assign responsibilities, and ensure compliance. 4. Integrate climate change considerations into nutrient management policies by addressing local-scale approaches. 5. Support the implementation of site-specific nutrient management strategies to enhance efficiency, reduce environmental impact, and tailor solutions to local conditions. 6. Enable inclusive, multi-stakeholder catchment governance platforms to lead local restoration efforts, supported by coherent top-down frameworks that integrate regulation, incentives, and advisory services to drive behavioural and systemic change.