River Alkalinity Enhancement as a Carbon Dioxide Removal Strategy: a Norwegian Case Study

Effective carbon dioxide removal (CDR) strategies are urgently needed to reduce the risks of climate change. Here, we propose a new strategy for ocean alkalinity enhancement that targets the land-to-ocean component of the inorganic carbon cycle: river alkalinity enhancement (RAE). RAE adapts freshwater acidification mitigation technology to capture CO2 through mineral weathering and by increasing rivers' capacity to retain and transport bicarbonate to long-term storage in the ocean. Global-scale modelling of RAE potential indicates that millions of tonnes of CDR per year is possible. We present data from an active project in Norway showing that RAE delivers ecological co-benefits, while meeting CDR criteria, including safety, scalability, permanence, and a simple quantification approach based directly on in-situ measurements.