Seven of the nine 'planetary boundaries' are exceeded with ocean acidification

The level of ocean acidification has exceeded the limit compatible with stable and sustainable ecosystems, exceeding seven of the nine 'planetary boundaries', the research institute that carries out these measurements said on Wednesday (24).

In 2009, about thirty researchers defined the concept of 'planetary boundaries' in a paper titled 'A Safe Space for Humanity.' At the time, they estimated that humanity had "crossed at least three planetary boundaries."

Since then, annual reports from the Potsdam Institute for Climate Research (PIK) have shown continued degradation. The 2025 report indicates that the "ocean acidification" threshold has just been surpassed.

“The ocean is acidifying, threatening marine life and leading to dangerous conditions, with the trend continuing to worsen,” the researchers wrote.

Although acidity is measured by pH, the reference for this limit is the concentration of aragonite, a mineral essential for the life of corals and shelled marine animals. The more acidic the ocean, the more aragonite disintegrates.

The minimum limit was set at 80% concentration in the pre-industrial era. And the oceans have fallen below that level.

"The pH at the ocean's surface has already decreased by approximately 0.1 since the beginning of the industrial era. This equates to an increase in acidity of between 30% and 40%," the scientists noted.

"This change threatens organisms that form calcium carbonate shells or skeletons, such as corals, mollusks, and crucial plankton species. The progressive disappearance of these organisms could alter the food chain," they explained.

The main cause of ocean acidification is the absorption of carbon dioxide (CO2), emitted by the burning of fossil fuels.

The other six widely exceeded limits relate to climate change, deforestation, biodiversity loss, the proliferation of synthetic chemicals (including plastics), freshwater scarcity, and the balance of the nitrogen cycle (agricultural inputs).

The two planetary limits that have not yet been overcome are aerosols in the atmosphere (air pollution) and the ozone level in the stratosphere.

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