Overview

• The Potsdam Institute for Climate Impact Research reports that aragonite levels have fallen below 80% of pre‑industrial concentrations, the threshold defining this boundary.
• Scientists warn the shift endangers corals, mollusks and crucial plankton, raising the risk of cascading disruptions to marine food webs.
• The institute notes a worsening trajectory, with surface ocean acidity up roughly 30–40% compared with pre‑industrial conditions.
• Six other planetary limits were already exceeded: climate change, biosphere integrity, land‑use change, freshwater alteration, biogeochemical flows and novel entities.
• Aerosol loading and the stratospheric ozone layer remain the only boundaries still within the safe operating space set out in the 2009 framework.