Enhanced rates of regional warming and ocean acidification after termination of large-scale ocean alkalinization

• Published in: Geophysical Research Letters
• Main Authors: Ferrer-Gonzalez, M., Ilyina, T., Sonntag, S., Schmidt, H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Ocean acidification
• Online Access: http://hdl.handle.net/21.11116/0000-0000-CF27-C; http://hdl.handle.net/21.11116/0000-0002-048C-C

Termination effects of large‐scale Artificial Ocean Alkalinization (AOA) have received little attention because AOA was assumed to pose low environmental risk. With the Max‐Planck‐Institute Earth System Model, we use emission‐driven AOA simulations following the Representative Concentration Pathway 8.5 (RCP8.5). We find that after termination of AOA warming trends in regions of the Northern hemisphere become ∼50% higher than those in RCP8.5 with rates similar to those caused by termination of solar geoengineering over the following three decades after cessation (up to 0.15 K/year). Rates of ocean acidification after termination of AOA outpace those in RCP8.5. In warm shallow regions where vulnerable coral reefs are located, decreasing trends in surface pH double (0.01 units/year) and the drop in the carbonate saturation state (Ω) becomes up to one order of magnitude larger (0.2 units/year). Thus, termination of AOA poses higher risks to biological systems sensitive to fast‐paced environmental changes than previously thought.