A sea turtle swims in a coral reef in Hawaii. Ocean acidification, found to be on the brink of crossing a boundary into higher-risk territory, can affect coral skeleton formation.

I feel like this should perhaps be bigger news?

Boundaries that have already been exceeded have to do with climate change, freshwater availability, biodiversity, land use, nutrient pollution (such as phosphorus and nitrogen) and the introduction of synthetic chemicals and plastics to the environment.

Ocean acidification is one of the systems that has not yet crossed its planetary boundary, along with ozone depletion and aerosols in the atmosphere. But while ocean acidification is still in the “green zone,” the new report finds it’s trending in the wrong direction. Scientists now say this metric is on the brink and may cross out of the safe zone in the next few years.

Earth’s oceans absorb carbon dioxide from the atmosphere, providing a valuable carbon sink as humans burn fossil fuels. But this process also makes the oceans more acidic, which can disturb the formation of shells and coral skeletons and affect fish life cycles, per the report.

As ocean acidification approaches the boundary, scientists are particularly concerned about certain regions, like the Arctic and Southern oceans. These areas are vital for carbon and global nutrient cycles, “which support marine productivity, biodiversity and global fisheries,” the report says.

Source: Smithsonian Magazine