Ocean acidification caused by CO2 absorption is altering marine chemistry in ways that harm fish behaviour, crustacean shells, and ecosystem stability, with significant implications for the welfare of billions of marine animals.
Ocean acidification creates welfare problems at multiple levels. Individual animals experience physiological stress from altered acid-base balance, sensory disruption that increases predation risk, and shell or skeleton dissolution that causes pain and vulnerability. At the ecosystem level, acidification compounds the effects of warming and pollution, degrading habitat quality and food availability for billions of marine animals. The welfare consequences are diffuse but enormous — a slow-motion crisis affecting organisms that cannot migrate to avoid changing conditions.