“Humanity is going beyond the limits of a safe operating space”. The synthesis of the Pik director, Johan Rockström, photographs the severe diagnosis contained in the new “Planetary Health Check 2025” report: with the first time of the border for the acidification of the oceans, seven out of nine systems of our planet pushed beyond the safety threshold for the first time of the acidification. A situation that, according to Scientists of the Potsdam Institute for Climate Impact Research, significantly increases the risk of irreversibly destroying the entire Earth’s ecosystem.
The seven limits now in the risk area are: climate change, integrity of the biosphere, change of the terrestrial system, use of fresh water, biogeochemical flows (nitrogen and phosphorus), introduction of new entities (such as plastic and chemical pollutants) and, in fact, acidification of the oceans. Everyone shows worsening trends.
The ocean, a giant under attack
The new and most significant development of the 2025 report concerns the health of the oceans. The continuous absorption of carbon dioxide with an atmosphere, mainly caused by the combustion of fossil fuels, is altering marine chemistry at an unprecedented pace. Since the beginning of the industrial era, the superficial pH of the oceans has decreased by about 0.1 units, which translates into an increase in acidity of 30-40%.
This phenomenon is not abstract, but has tangible consequences. The scientific indicator used, the state of saturation of the Aragonite (a form of calcium carbonate), descended to the value of 2.84, exceeding the safety threshold set at 2.86. This threshold, however, has been recalibrated and made more stringent after a new evaluation of the pre -industrial conditions, highlighting how the current situation is even more serious than previously thought. Acidification makes it more difficult for organisms such as corals, molluscs and plankton to build its shells and skeletons. The first signs are already visible: tiny sea snails, the pteroopods, already show signs of damage to the shell. Being the basis of many food chains, their decline risks triggering cascade effects on the entire ecosystem.
“The movement we are witnessing goes absolutely in the wrong direction,” commented Levke Caesar, co-responsible for the Planetary Boundaries Science Lab and the main author of the relationship. “The oceans are becoming more acidic, oxygen levels are lowering and the waves of marine heat are increasing. The consequences affect food safety, on the stability of the global climate and human well -being”. An urgency reiterated by the Oceanografa Sylvia Earle, Planetary Guardian: “Today acidification is a flashing red light on the dashboard of the stability of the earth. I ignoring it, we risk collapse the foundations of our living world. We protect the ocean and protect ourselves”.
An interconnected system under pressure
Overcoming a new border is not an isolated event. The report underlines how the nine systems are deeply interconnected. Damage in one sector affects others, amplifying the risks. “The interconconnections between the planetary borders show how a planet under pressure, both local and global level, can have an impact on all, everywhere,” added Boris Sakschewwski, co-responsible for the laboratory and the main author. Guaranteeing human well -being requires a holistic approach that considers the planet as a single, complex organism.
Hope in concrete actions
Despite the severe diagnosis, the relationship leaves a window of hope open. Two planetary limits remain within the safety area: the load of atmospheric aerosol (linked to the pollution by particulates) and the thinning of the stratospheric ozone layer. These two successes are not random, but the direct result of decades of targeted international actions, such as the Montreal protocol for ozone and regulations on polluting emissions. Global aerosol emissions are down and the ozone layer has largely taken up again.
This shows that, when political will and global cooperation exists, it is possible to reverse negative trends. As Johan Rockström concludes: “We are witnessing a widespread decline in the health of our planet. But this is not an inevitable result. (…) Even if the diagnosis is disastrous, the care window is still open. The failure is not inevitable; bankruptcy is a choice. A choice that must and can be avoided”.
