Climate change drives rapid decadal acidification in the Arctic Ocean from 1994 to 2020

• Published in: Science
• Main Authors: Qi, Di, Ouyang, Zhangxian, Chen, Liqi, Wu, Yingxu, Lei, Ruibo, Chen, Baoshan, Feely, Richard A., Anderson, Leif G., Zhong, Wenli, Lin, Hongmei, Polukhin, Alexander, Zhang, Yixing, Zhang, Yongli, Bi, Haibo, Lin, Xinyu, Luo, Yiming, Zhuang, Yanpei, He, Jianfeng, Chen, Jianfang, Cai, Wei-Jun
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2022
• Subjects: Arctic; Arctic Ocean; Climate change; Ocean acidification; Sea ice
• Online Access: http://dx.doi.org/10.1126/science.abo0383; https://www.science.org/doi/pdf/10.1126/science.abo0383

The Arctic Ocean has experienced rapid warming and sea ice loss in recent decades, becoming the first open-ocean basin to experience widespread aragonite undersaturation [saturation state of aragonite (Ω arag ) < 1]. However, its trend toward long-term ocean acidification and the underlying mechanisms remain undocumented. Here, we report rapid acidification there, with rates three to four times higher than in other ocean basins, and attribute it to changing sea ice coverage on a decadal time scale. Sea ice melt exposes seawater to the atmosphere and promotes rapid uptake of atmospheric carbon dioxide, lowering its alkalinity and buffer capacity and thus leading to sharp declines in pH and Ω arag . We predict a further decrease in pH, particularly at higher latitudes where sea ice retreat is active, whereas Arctic warming may counteract decreases in Ω arag in the future.