The article didn't state this, does anyone know the actual pH change? The oceans are so large and so buffered I'm surprised the magnitude of pH change would be so dramatic.
"In the 200-plus years since the industrial revolution began, the concentration of carbon dioxide (CO2) in the atmosphere has increased due to humans burning fossil fuels (such as car emissions) and changing the way land is used (such as deforestation). During this time, the pH of surface ocean waters has fallen by 0.1 pH units. The pH scale, like the Richter scale, is logarithmic, so this change represents approximately a 30 percent increase in acidity."
https://www.noaa.gov/education/resource-collections/ocean-co...
The carbon dioxide isn't distributed evenly throughout the volume of the oceans. The pH change would be significantly slower if the whole volume could equilibrate instantaneously.
https://www.whoi.edu/know-your-ocean/ocean-topics/ocean-chem...
Currently, about half of the anthropogenic (human-caused) carbon dioxide in the ocean is found in the upper 400 meters (1,200 feet) of the water column, while the other half has penetrated into the lower thermocline and deep ocean. Density- and wind-driven circulation help mix the surface and deep waters in some high latitude and coastal regions, but for much of the open ocean, deep pH changes are expected to lag surface pH changes by a few centuries.
This is especially a problem for oceanic life because the vast majority of biological productivity and food people eat is also found in that upper portion. The euphotic zone where most photosynthesis takes place extends to about 200 meters below the surface.