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Global Boundary for Ocean Acidification may have been broken Hans-Peter Plag Published in Library on Jun. 11, 2025. A new study shows that ocean acidification has already crossed a crucial threshold for planetary health. Share

A new study by Findlay et al. (2025) published in Global Change Biology finds that up to 60% of the global subsurface ocean (down to 200 m) has crossed the boundary for ocean acidification. This indicates that seven out of the nine global boundaries have been crossed. The findings show that acidification in the ocean is progressing faster than expected. The map (from Findlay et al.) shows the percentage difference in surface Aragonite saturation state (Ω^Arag between pre-industrial (1750) and year 2020. The black contour line on the map represents a 20% reduction from pre-industrial values. This quantity is used as an indicator for the global boundary in ocean acidification.

Lisa Bachelor summarizes the paper's findings and comments on the implication for the marine biosphere in her article “‘Ticking timebomb’: sea acidity has reached critical levels, threatening entire ecosystems – study” published in The Guardian on June 9, 2025. In a second article published the same day and title “How the ‘evil twin’ of the climate crisis is threatening our oceans” she points out that while all across the ocean the pH levels are falling, scientists are increasingly frustrated that the problem is not being taken seriously enough. There is what seems to be willful ignorance and negligence in the governments and large business of this existential threat.

Rothman (2017) found that with the current trends in carbon absorption in the ocean a carbon overload making life in the ocean nearly impossible may be reached by 2100 plus/minus 50 years. The new scientific findings indicate that the oceans might be heading for the lower limit of that range, i.e., 2050.