Example
Changing carbonate chemistry affects organisms that build shells or skeletons.
The catch
Acidification means a shift towards lower pH, even while seawater remains alkaline.
Related terms
Afforestation, Biodiversity, Blue carbon, Carbon sink, Carbon stock, Deforestation
In more depth
Ocean acidification, explained.
Ocean acidification depends on how much carbon dioxide the air holds, whatever happens to temperature, so only cuts and removals of CO₂ can slow it. Methane reductions or any scheme to reflect sunlight would leave it untouched.
The ocean is a major carbon sink and has absorbed a large share of human CO₂ emissions. Dissolved CO₂ forms carbonic acid, and the extra hydrogen ions bind carbonate, the building block that corals, oysters and some plankton need to build their hard parts. Shellfish hatcheries on some coasts already adjust the chemistry of the water they draw in. Damage varies by species and region, and it combines with warming and oxygen loss. Express it as a change in pH or carbonate saturation against a stated baseline.