Global coral reefs get less time to recover as oceans heat up, report finds

The most comprehensive global reef assessment yet, drawing on 21.1 million observations across 123 countries and territories, finds average hard coral cover fell from 30.2% in 1980-2009 to 27.3% in 2020-2024, dropping further to 25.8% in 2024. The report calls this a conservative estimate, since monitoring began after many reefs were already degraded.

A fourth global bleaching event from 2023 to mid-2025 drove an 8.9% relative drop in coral cover in a single year, the largest on record, and researchers warn a fifth event may be forming for 2026 as a strong El Niño develops. Bleaching events that once struck roughly once a decade now arrive every four to six years, leaving reefs less time to recover between hits.

Regional damage varies sharply: the northern Arabian Sea, Persian Gulf and Gulf of Oman lost 48.7% of coral cover and the Caribbean lost 43.4%, while South Asia and the Western Indian Ocean showed increases the report cautions may reflect degraded starting points rather than genuine recovery. Outside experts described the outlook as dire, with one comparing restoration efforts without emissions cuts to rearranging deck chairs on the Titanic.

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