Roughly one-third of the CO2 that humans have so far pumped into the air has been absorbed by the oceans. This comes to a stunning 150 million metric tons. As with most aspects of the Anthropocene, though, it’s not only the scale of the transfer but also the speed that’s significant. A useful (though admittedly imperfect comparison can be made to alcohol. Just as it makes a big difference to your blood chemistry whether you take a month to go through a six-pack or an hour, it makes a big difference to marine chemistry whether carbon dioxide is added over the course of a million years or a hundred. To the oceans, as to the human liver, rate matters.
— Chapter Six: The Sea Around Us, The Sixth Extinction