The world’s oceans have crossed a critical threshold of acidity for the first time, according to the latest Planetary Health Check from the Potsdam Institute for Climate Impact Research. Scientists say the shift, driven by fossil fuel emissions, threatens marine life and global climate stability.
Since the industrial era, ocean surface pH has fallen by about 0.1 units, increasing acidity by up to 40%. This disrupts calcium carbonate formation, harming corals, molluscs and shellfish, and indirectly affecting species like salmon and whales. Researchers warn of risks to food security and coastal economies, as well as the ocean’s ability to absorb heat and capture carbon dioxide.
The report confirms that seven of nine planetary boundaries have now been breached, including climate change, freshwater use and biosphere integrity. Authors highlight cold-water corals, tropical reefs and Arctic ecosystems as particularly vulnerable.
Levke Caesar, co-lead of the Planetary Boundaries Science Lab, said the findings were frightening but reversible if fossil fuel use and pollution are cut. The report notes past global cooperation, such as the Montreal protocol, shows recovery is possible.
Institute director Johan Rockström urged urgent action: “Even if the diagnosis is dire, the window of cure is still open. Failure is not inevitable; failure is a choice.”
