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Published
Ocean surface pH at Station ALOHA edged up to 8.042 in 2024, but the ten-year trend still points down
Ocean surface pH (Station ALOHA) · seen · published
At Station ALOHA, the long-running ocean monitoring site north of Hawaii, surface seawater pH was recorded at 8.042414 for 2024, up from 8.037277 in 2023 — a change of +0.06%. Over the last ten years of the same series the direction is the other way: about -0.4% per decade, the signature of an ocean absorbing carbon dioxide from the air and becoming less alkaline. A single better year does not bend that trend. What this is not: this is one station, not the whole ocean, so it cannot tell you what is happening in other basins or at depth. The 2024 uptick may reflect year-to-year swings in circulation, temperature and biology — 2024 sat in an El Niño phase (ONI 1.8) — rather than any change in the underlying chemistry. Annual indicator series can also lag reality and be revised later. The re-read on 27 September 2026 returned the same value, 8.042414, which shows the provider has not revised the figure; it is the same source, not an independent measurement. What would change our mind: a revised back-series from the Hawaii Ocean Time-series, a changed upstream method, or several more years above trend.
Written by AI, then checked by a separate reviewer before publication. Every claim points at the evidence below.
What we saw
owid-grapher — Ocean surface pH (Station ALOHA): 2024 = 8.042414 (2023 = 8.037277) pH; 10-year trend -0.4% per decade (worsening). Upstream: Hawaii Ocean Time-series (Univ. of Hawaii). (Jan 1, 2024)See the source ↗
owid-grapher — Re-read on 2026-09-27: 2024 value unchanged at 8.042414 — the source has not revised it. Same provider (data stability, not an independent measurement). (Jan 1, 2024)See the source ↗
What it might not be
Single site (Station ALOHA, Hawaii), not a global average; regional differences are hidden.
Confirmation is a re-read from the same provider — it proves no revision, not an independent measurement.
Annual indicators can lag reality by 1–5 years.
Uncertainty bands for the series are not shown here.
Upstream method changes or a revised back-series could alter both the 2024 value and the trend.
One year moving against the ten-year trend is expected and does not reverse it.
Annual global indicators lag reality by 1–5 years: a 'new' value can describe a year long past.
The direction is the 10-year trend, not the single year: one year can move against the trend, and the title then says so.
Global aggregates hide where it happens — a stable global number can mask collapse in one region and recovery in another.
Confirmation only proves the source did not revise the number on a later read — same provider, not an independent measurement.
Some series are single sites (ocean pH is Station ALOHA, Hawaii) or modelled composites (Living Planet Index) with wide uncertainty bands we do not show.
Upstream methods change between releases; a revised back-series can make a year look new or change the trend.
What would change our mind
Newer satellite images that show no change, a correction from the data source, or a reply with evidence from the ground. If that happens, the case is marked “Turned out wrong” — in public — and it stays on this site.
Why this was published
Two separate sources agreed — owid-grapher, then owid-grapher — and a reviewer checked the evidence before it went up.
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Re-read on 2026-09-27: 2024 value unchanged at 8.042414 — the source has not revised it. Same provider (data stability, not an independent measurement).