Gas hydrate dissociation prolongs acidification of the Anthropocene oceans

Anthropogenic warming of the oceans can release methane (CH 4 ) currently stored in sediments as gas hydrates. This CH 4 will be oxidized to CO 2 , thus increasing the acidification of the oceans. We employ a biogeochemical model of the multimillennial carbon cycle to determine the evolution of the oceanic dissolved carbonate system over the next 13 kyr in response to CO 2 from gas hydrates, combined with a reasonable scenario for long‐term anthropogenic CO 2 emissions. Hydrate‐derived CO 2 will appreciably delay the neutralization of ocean acidity and the return to preindustrial‐like conditions. This finding is the same with CH 4 release and oxidation in either the deep ocean or the atmosphere. A change in CaCO 3 export, coupled to CH 4 release, would intensify the transient rise of the carbonate compensation depth, without producing any changes to the long‐term evolution of the carbonate system. Overall, gas hydrate destabilization implies a moderate additional perturbation to the carbonate system of the Anthropocene oceans.