Phytoplankton are the biggest producers of oxygen on the planet. Not trees. Mass die outs of phytoplankton is an end game scenario.

The other effect is that most gas’s solubility in liquid decreases with temperature. If you leave your can of soda out on a hot day, you can see this in action.

Our ocean is the our biggest “carbon sink.” As it heats, it can hold less, shifting the chemical equilibrium to release more CO2 in the atmosphere.

I’m wondering if that could counter the ocean acidification effect over a long time - if we could get a negative feedback loop that would counteract the effects of increasing pH.

We are already having issues with commercial mussel production - the ocean needs to be a basic environment for oysters and mollusks and other creatures to build their shells. In a 7.8-8.1 environment, we are going to have serious problems with those species.

Another concerning thing is the ice-albedo positive feedback loop. Sea ice is more reflective than dark ocean water. Dark ocean water warms, melts the sea ice, and then exposes even more dark ocean water to heat.