Ocean afforestation is a potentially effective way to remove carbon dioxide
Wei‐Lei Wang, Mar Fernández‐Méndez, Franziska Elmer, Guang Gao, Yangyang Zhao, Y F Han, Jiandong Li, Fei Chai, Minhan Dai
Abstract
Ocean afforestation has been proposed as a potential means of carbon dioxide (CO 2 ) removal (CDR). However, a recent paper 1 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 CO 2 influx into the surface seawater, after CO 2 fixation by Sargassum , takes 2.5–18 times longer than the time that surface seawater is in contact with the atmosphere. Here, we 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. We support that thorough evaluations are essential before implementing any large-scale ocean-based CDR methods to avoid major negative consequences 2 , and ocean afforestation as a means of CDR is also such a case.