9th December 2026
Ocean health: acidification
One of the nine planetary boundaries is ocean acidification. If the oceans become too acidic it endangers marine life and therefore the lives of the rest of us who are dependent on healthy oceans.
The 2025 Planetary Health Check showed that this planetary boundary has been breached: since the start of the industrial era, the oceans’ acidity has increased by 30-40% destabilising this important Earth systems. (1)
What is ocean acidification?
“For millions of years, the ocean has acted as Earth’s carbon sponge, quietly absorbing carbon dioxide (CO₂) from the air. But that natural partnership has turned toxic in the age of fossil fuels.
“As humanity has pumped unprecedented levels of CO₂ into the atmosphere, the oceans have taken in more and more of it—now absorbing roughly a quarter of all carbon emissions. But this uptake comes at a cost. When carbon dioxide dissolves in seawater, it undergoes a chemical transformation, forming carbonic acid. That acidification strips the ocean of carbonate ions—essential building blocks for creatures like corals, clams, and countless shell-forming organisms.
“As their calcium carbonate shells thin and weaken, so too do the coral reefs and underwater habitats they support. A weakened foundation means collapsing ecosystems—once-thriving marine gardens reduced to skeletal remains.” (2)
(1) https://www.stockholmresilience.org/research/planetary-boundaries.html
(2) https://www.sciencenewstoday.org/parts-of-earths-oceans-have-quietly-crossed-a-dangerous-threshold
The Green Tau 