https://phys.org/news/2018-07-ocean-acidification-million-years.html

Around a third of the CO2 released by burning coal, oil and gas gets dissolved into the oceans. Since the beginning of the industrial era, the ocean has absorbed around 525 billion tons of CO2, equivalent to around 22 million tons per day.

The rapid influx of CO2 in to the oceans is severely threatening marine life, with the shells of some animals already dissolving in the more acidic seawater.