Nature – Wang et al. (2023): Ocean afforestation is a potentially effective way to remove carbon dioxide

Wei-Lei Wang, Mar Fernández-Méndez, Franziska Elmer, Guang Gao, Yangyang Zhao, Yuye Han, Jiandong Li, Fei Chai, Minhan Dai IN: Nature Communication, 14, https://doi.org/10.1038/s41467-023-39926-z

Ocean afforestation has been proposed as a potential means of carbon dioxide (CO₂) removal (CDR). However, a recent paper concludes that the efficacy of ocean afforestation may be reduced by 20–100% due to two biogeochemical feedbacks: calcification by epibionts and nutrient reallocation, it also suggests that atmospheric CO₂ influx into the surface seawater, after CO₂ fixation by Sargassum, takes 2.5–18 times longer than the time that surface seawater is in contact with the atmosphere. Here, the authors argue that these findings were technically biased due to utilization of selective data and evidence, and the conclusion drawn is thus insufficiently supported and maybe misleading. 

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