See my sibling answer next to yours for an explanation of why the oceans were not then acidic despite the higher atmospheric CO2 levels. If you wait a few thou

See my sibling answer next to yours for an explanation of why the oceans were not then acidic despite the higher atmospheric CO2 levels. If you wait a few thousand years, ours won't be either. But shellfish who depend on their calcium bicarbonate shells not dissolving can't afford to wait a few thousand years while bathed in a mild acid...