Global study finds riverine carbon to nutrient ratios diverging under climate and land use change

A new study in npj Clean Water analyzed 20 years of data from over 5,000 catchments worldwide and found that 73% of rivers show divergent trends in dissolved carbon, nitrogen, and phosphorus ratios. This means carbon is declining relative to nutrients in most rivers, which can affect downstream eutrophication, oxygen levels, and greenhouse gas emissions. The research links these shifts to river warming, agricultural expansion, and forest loss. As land use and climate change alter nutrient inputs at different rates, the balance that controls whether carbon and nutrients are stored or released downstream is breaking down. The findings have implications for water quality management and carbon cycle modeling. For carbon market participants, the study highlights how land use decisions and climate feedbacks directly alter freshwater carbon dynamics. Understanding these stoichiometric shifts could inform better accounting of inland water carbon fluxes and the design of nature based solutions that target both carbon and nutrient retention.