Ocean Acidification: How Rising CO₂ Is Changing the Chemistry of the Sea

Tropical coral reef showing healthy vibrant corals alongside bleached and dissolving coral skeletons illustrating acidification damage

As atmospheric CO₂ rises, the ocean absorbs roughly a quarter of it—triggering a cascade of chemical reactions that lower seawater pH and threaten marine life from coral reefs to commercial fisheries. Here is what the science actually shows.