The World’s Oceans Are a ‘Ticking Time Bomb,’ Reaching Dangerous Acidification Levels Earlier Than Scientists Thought
Ocean acidification has crossed “planetary boundaries” in some parts of the ocean, deepening a crisis facing the planet’s marine ecosystems.

By Georgina Gustin
June 9, 2025

A critical measure of the ocean’s health suggests that the world’s marine systems are in greater peril than scientists had previously realized and that parts of the ocean have already reached dangerous tipping points.

A study, published Monday in the journal Global Change Biology, found that ocean acidification—the process in which the world’s oceans absorb excess carbon dioxide from the atmosphere, becoming more acidic—crossed a “planetary boundary” five years ago.

“A lot of people think it’s not so bad,” said Nina Bednaršek, one of the study’s authors and a senior researcher at Oregon State University. “But what we’re showing is that all of the changes that were projected, and even more so, are already happening—in all corners of the world, from the most pristine to the little corner you care about. We have not changed just one bay, we have changed the whole ocean on a global level.”

The new study, also authored by researchers at the U.K.’s Plymouth Marine Laboratory and the National Oceanic and Atmospheric Administration (NOAA), finds that by 2020 the world’s oceans were already very close to the “danger zone” for ocean acidity, and in some regions had already crossed into it.

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