As oceans absorb atmospheric carbon dioxide, increasing acidification disrupts the physiology, behaviour, and survival of marine animals from corals to fish, with growing welfare implications.
Ocean acidification represents a slow-motion welfare crisis for marine life. Shell-forming invertebrates experiencing shell dissolution face a form of chronic physiological stress as the acidic conditions undermine their primary defence structure. Fish larvae with disrupted predator avoidance behaviour are more likely to be consumed, but survivors of acidification-damaged reefs face degraded habitats and altered food webs. The welfare implications of widespread physiological disruption across ocean ecosystems are vast and undercharacterised — acidification affects the neurobiology, respiration, and acid-base balance of virtually all marine organisms. Addressing ocean acidification requires reducing atmospheric CO2, making it inseparable from broader climate action.