Accelerated aged carbon release from the cryosphere during past three decades

The cryosphere is highly sensitive to climate change, and melting-induced carbon release through river systems has likely shifted over past decades. Long-term carbon isotopes of riverine organic carbon provide critical insights into climate driven cryospheric carbon export. In glacial influenced high mountain catchments, dissolved organic carbon (DOC) is ¹⁴C depleted, whereas contributions of permafrost derived aged carbon to Arctic rivers remain limited. Elevated proportions of petrogenic particulate organic carbon (POC) in glacial dominated high mountain catchments reflect glacial erosion or precipitation-driven physical erosion. Meanwhile, Arctic rivers have experienced rising inputs of permafrost derived POC, reflecting intensified thaw. Overall, these trends demonstrate an increasingly dynamic cryospheric response to ongoing climate warming.