Editing IPCC:AR6/WGI/Chapter-5 (section)

==== 5.3.4.2 Reversal of Ocean Acidification by Carbon Dioxide Removal ====

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Reversing the increase in atmospheric CO <sub>2</sub> concentrations through negative emissions ( [[#5.6|Section 5.6]] ) will reverse ocean acidification at the sea surface ( ''high confidence'' ) but will not result in rapid amelioration of ocean acidification in the deeper ocean ( [[#5.3.3.2|Section 5.3.3.2]] ). The ocean’s uptake of atmospheric CO <sub>2</sub> will start to decrease as atmospheric CO <sub>2</sub> decreases (Sections 5.4.5, 5.4.10 and 5.6.2.1; [[#Mathesius--2015|Mathesius et al., 2015]] ; [[#Tokarska--2015|Tokarska and Zickfeld, 2015]] ). However, because of the long time scales of the ocean turnover that transfers CO <sub>2</sub> from the upper to the deep ocean, excess carbon will continue to accumulate in the deep ocean even after a decrease in atmospheric CO <sub>2</sub> ( [[#Cao--2014|Cao et al., 2014]] ; [[#Mathesius--2015|Mathesius et al., 2015]] ; [[#Tokarska--2015|Tokarska and Zickfeld, 2015]] ; T. [[#Li--2020|]] [[#Li--2020|Li et al., 2020]] ). There is thus ''high confidence'' that CO <sub>2</sub> emissions leave a long-term legacy in ocean acidification, and are therefore irreversible at multi-human generational scales, even with aggressive atmospheric CO <sub>2</sub> removal.

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