Overview

• The Potsdam Institute’s 2025 assessment concludes ocean acidity has crossed a critical threshold for marine life.
• The designation reflects new measurements and revised calculations alongside worsening conditions observed since last year.
• Seven of nine planetary boundaries are now exceeded, with all seven under increasing pressure.
• Oceans absorbing roughly 30% of human CO2 have seen surface pH fall by about 0.1, increasing acidity by 30–40% since the industrial era.
• Scientists warn of heightened threats to corals, shellfish, Arctic species, fisheries and coastal economies, even as ozone recovery and falling aerosols show policy can work.