Published 2026-05-01 · data 2023 · percent of pre-industrial surface pH
The ocean is thirty percent more acidic
CO₂ dissolves into seawater as carbonic acid. Shell-forming creatures feel it first.
Since the industrial era, the ocean has absorbed our carbon and paid for it in chemistry: surface seawater is now roughly 30% more acidic, as CO₂ dissolves into carbonic acid. A 0.1 drop in pH sounds small — it isn't. Shell-forming creatures feel it first, and the food webs that depend on them feel it next.
1 cell = 0.1 percent of pre-industrial surface pH (0.1% of surface ocean acidity change) · 1,000 cells
Context
The chemistry is straightforward: as atmospheric CO₂ rises, more of it dissolves into seawater as carbonic acid. NOAA puts the result at roughly a 30% increase in surface-ocean acidity — hydrogen ion concentration — since the industrial era, equal to a drop of about 0.1 pH.
Shell-forming creatures feel it first, because acidified seawater makes it harder to build and maintain shells and skeletons — from oysters and corals to the tiny drifting pteropods that sit near the base of marine food webs. Strain at the bottom travels upward.
On the grid, that human-driven 30% is set against the ocean's natural baseline (70%), separating what we have added from what was always there. Figures per NOAA, data year 2023.
NOAA: ~30% increase in H⁺ since industrial era (~0.1 pH drop).
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Credit this grid as Inagrid — https://inagrid.com/e/2026-05-01-ocean-acidification