Global spatiotemporal characterization factors for freshwater eutrophication under climate change scenarios

Nutrient enrichment of water bodies can lead to eutrophication, which poses a global threat to freshwater ecosystems, affecting biodiversity and water quality. While human activities have accelerated eutrophication, climate change further complicates the dynamics of nutrient cycling and ecosystem responses. Here, we provide global, spatially explicit freshwater eutrophication characterization factors, at an annual resolution from 2021 up to 2099 based on eight different climate change scenarios. A substantial spatial and temporal variability is identified, with higher characterization factors observed in tropical and arid regions, as well as densely populated areas, revealing a location-specific influence of climate change on eutrophication impacts. A comparison between different Representative Concentration Pathway scenarios suggests that climate change intensifies the eutrophication impact of phosphorus and its fluctuations, with hotspots identified in central and south America, Australia, southeastern Asia, central Africa and eastern Europe. Results highlight the importance of spatially- and temporally-explicit characterization factors, especially in prospective life cycle assessments. Finally, novel insights are provided into the complex interactions between nutrient fate, hydrological dynamics, and climate change, crucial for the development of phosphorus emission control strategies and the protection of freshwater ecosystems.