50 per cent

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title: "50 per cent" claim: "Coral cover in the Great Barrier Reef has declined by 50 per cent in just 27 years." caption: "The paper that minted the 50 also named the storms. The slogan kept the fraction." status: featured example: false published: 2026-08-15T18:01:00+10:00 person: CSIRO claimType: no-evidence-required year: 2012 tags: [gbr, csiro, aims, coral, ridd, "2012"] source: url: https://www.csiro.au/en/research/natural-environment/oceans/ereefs-management-system date: "2012-10-01" publisher: CSIRO title: "Ensuring a vital future for the Great Barrier Reef" quote: "Coral cover in the Great Barrier Reef has declined by 50 per cent in just 27 years" evidence: path: 2012/fifty-per-cent/source.md kind: note captured: "2026-08-14"

CSIRO, still on the eReefs page: coral cover “has declined by 50 per cent in just 27 years.” The footnote is De’ath, Fabricius, Sweatman and Puotinen, PNAS 2012 — AIMS authors, 1985–2012. That paper is the mint.

This card files that fraction. It does not file “no coral died.”

What did have a receipt:

• The same PNAS paper split the loss: tropical cyclones 48%, crown-of-thorns 42%, bleaching 10%. The slogan is the 50. The storms are the second sentence.
• Peter Ridd, Senate: the 50 is treated as a one-way death. He noted the 2011–2016 recovery after Yasi that some society papers skipped. AIMS’s own later series made his point without his name on it.
• AIMS 2022: northern 36%, central 33% — regional highs in the 36-year record. AIMS 2026: northern 35.1%, still above the long-term 27%. A 50% decline to 2012 and a record high a decade later are both in the government ledger. The slogan only kept the first.

Grammar: 50 per cent, 27 years. Logic: a cyclone year is not a tombstone. Rhetoric: declined.