CO₂ absorption, pH drop, and impact on marine shells
Hover ocean to see local pH · Adjust CO₂ to see ecosystem effects
Oceans absorb ~30% of atmospheric CO₂. CO₂ + H₂O → H₂CO₃ (carbonic acid), lowering pH. Pre-industrial ocean pH was ~8.2; today it's ~8.07. Even small pH drops reduce carbonate ions (CO₃²⁻) that shellfish and corals need to build CaCO₃ skeletons. Below pH 7.8, dissolution of shells accelerates. Coral bleaching increases with acidification and warming.