Dissolved Organic Carbon Fluxes to Oceans under Climate Change

Climate change is a primary concern in the coming decades and affects temporal and spatial patterns in temperature and hydrology worldwide. These variations will undoubtedly affect the global carbon balance. The export of riverine dissolved organic carbon (DOC) to oceans is crucial in the carbon balance and oceanic food web maintenance. Recent modelling quantified current daily DOC exports and future daily discharges delivered to the oceans. We intend to quantify future daily DOC deliveries from large rivers with a generic model integrating future temperature and hydrological dynamics under changing climate. On a set of 308 large rivers, we found significant increases in global DOC exports to the oceans of + 5.9% ± 0.1% for RCP 2.6 and + 14.6% ± 0.1% for RCP 8.5. Among all watersheds, Arctic catchments returned the largest rises of + 19.1% ± 0.4% for RCP 2.6 and of + 38.0% ± 0.1% for RCP 8.5. It highlights the high variability in future DOC deliveries, affecting future carbon transport to the oceans, especially in Arctic areas. These increases might affect the local and global sustainability of aquatic ecosystems.