Abiotic CO2 Sequestration via River Runoff: A Potential "Missing Sink" Dampening Atmospheric Warming?

Abstract. The international system for greenhouse gas emission accounting relies on national emission and absorption accounting. The effectiveness of these systems in accounting for carbon sinks is questionable due to the complexities of local carbon dioxide control in the atmosphere and uncertainties in forestry carbon balance assessments. This review proposes that irreversible abiotic mechanisms for removing carbon from the cycle of substances should play a major role in carbon sink accounting, as a complement to biotic carbon capture. While the capture and fixation of carbon by ecosystems is a reversible process and represents only the first step toward its removal from the atmosphere, subsequent steps leading to irreversible carbon sequestration depend mainly on the interaction of ecosystems with water flows that form continental runoff. This paper provides estimates that suggest a significant increase in previously existing values of carbon removal via river runoff, and concludes that continental runoff is a primary mechanism leading to long-term carbon sequestration.