A post-El Niño coral reassessment may find over half of species at elevated risk, IPBES chair says
IPBES chair David Obura told AFP that a forecast record El Niño adds "a terrifying level of additional risk" for coral reefs. His Nature review, completed in 2020, put nearly half of species at elevated risk; a new count could pass 50%, he said.
The Scientist · Science desk
World reefs: Obura told AFP a super El Niño poses a threat he called terrifying. Pacific: sea temperatures at all-time highs. Coral species: nearly half at elevated extinction risk by 2020 (Nature). Bleaching: record 2023-2025 episode caused widespread reef mortality.
- Who's exposed exposure The world's coral reefs Obura told AFP a super El Niño fueling record ocean temperatures poses a threat he called terrifying, claim 1
- Who's exposed exposure Pacific waters Sea surface temperatures in parts of the Pacific have hit all-time highs months before the El Niño's expected peak, claim 3
- What it sets up precedent Coral species By 2020, nearly half were at elevated relative risk of extinction, climate change the main driver, the Nature study wrote, claim 6
- What it sets up precedent Coral reefs The worst coral bleaching on record, between 2023 and 2025, caused widespread mortality across reefs, claim 8
| Who | How | Kind | Claim |
|---|---|---|---|
| The world's coral reefs | Obura told AFP a super El Niño fueling record ocean temperatures poses a threat he called terrifying | exposure | 1 |
| Pacific waters | Sea surface temperatures in parts of the Pacific have hit all-time highs months before the El Niño's expected peak | exposure | 3 |
| Coral species | By 2020, nearly half were at elevated relative risk of extinction, climate change the main driver, the Nature study wrote | precedent | 6 |
| Coral reefs | The worst coral bleaching on record, between 2023 and 2025, caused widespread mortality across reefs | precedent | 8 |
What happened
- Global forecasters expect this El Niño to be the strongest on record, and Pacific sea surface temperatures have already hit all-time highs months before the expected peak.
- Obura said the coming event is worse than the 1997/98 super El Niño, after three intervening global bleaching events.
- The Nature review he led covered hundreds of IUCN red list species, including staghorn and table corals, and found a sharp deterioration since the 2008 global census.
Why it matters
- Who's exposed exposure In the Nature paper's projections, warming and other pressures mainly set when and where conditions become unviable for corals, so regional timing is the open variable.
- What it limits constraint The published nearly-half figure is a 2020 count, so any higher number, including Obura's 50% mark, is a projection until someone reassesses.
- Who has to decide decision Testing the 50% call takes a new reassessment after the event, on a faster schedule than the last one needed.
Obura presented the 50% figure as a forecast, distinct from the review's measured count of nearly half. "It is entirely possible that reassessing the status of corals just after this coming El Niño may show them to have crossed the 50% mark of the proportion of species at elevated risk of extinction," he said [13].
The review cannot separate how much of any rise would come from the El Niño. The review's data stop in 2020 [7]. The 2023 to 2025 bleaching episode, the worst on record, came after that cutoff and caused widespread mortality across reefs [8]. A later count that crossed 50% would reflect that episode as well.
The review's unit is also narrower than the word "extinction" suggests. It covered hundreds of species on the IUCN red list, among them staghorn and table corals, and it counted species at elevated relative risk of extinction [c5, c6].
Obura is open about how wide his own uncertainty is on timing. "When they hit their threshold the collapse of reefs in that region could be precipitous and we don't know if that is five, 15 or 30 years into the future, or maybe this year with the super El Niño ramping up?" he said [12].
The El Niño signal comes from one place. The forecast and the temperature records reach readers through a single AFP report quoting Obura, who also led the Nature review [c3, c5]. The report does not name the forecasters or give the temperature anomalies.
We think the direction of risk is well supported by what is reported: record Pacific temperatures before the expected peak, and widespread mortality in 2023 to 2025. The size of the change is Obura's estimate. The last assessment was completed in 2020 and published in 2026, a gap of six years [10], so a count taken just after this El Niño would need a much faster turnaround.
What to watch
- Whether Pacific sea surface temperatures keep climbing past the current all-time highs, and where the El Niño peaks.
- Reef surveys during the event: reports of widespread coral mortality would be the first direct evidence for Obura's warning.
- Any announced reassessment of coral red list status after the El Niño, and how quickly it reports.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap+25
- Incentives
- Insufficient
- Confidence45
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
David Obura, chair of IPBES, the U.N.'s expert scientific panel on biodiversity, told AFP that a super El Niño fueling record ocean temperatures poses a threat he called terrifying to the world's coral reefs.
- [2]
This year's El Niño layers "a terrifying level of additional risk," said Obura.
- [3]
Global forecasters expect this El Niño to be the strongest on record, and sea surface temperatures in parts of the Pacific have already hit all-time highs months before its expected peak.
- [4]
Obura recalled the damaging impact of the 1997/98 super El Niño and said: "That this coming event is worse than that, after three intervening global bleaching events ... is a terrifying reality."
- [5]
Obura led a reassessment of coral health published in Nature that reported a sharp deterioration in reef-building species since the last global census in 2008; it covered hundreds of species on the IUCN red list, including staghorn and table corals.
- [6]
The Nature study's authors wrote: "Our results show that by 2020, nearly half of coral species were at elevated relative risk of extinction," with climate change the main driver of the decline.
- [7]
The study was completed in 2020, and Obura said the findings today would be even bleaker.
- [8]
Global ocean temperatures have soared to unprecedented highs since 2020, and the worst coral bleaching episode on record, between 2023 and 2025, caused widespread mortality across reefs.
- [9]
The Nature paper, 'Nearly half of reef-building corals face elevated relative risk of extinction' by David Obura, is dated 2026 (DOI 10.1038/s41586-026-11263-3).
- [10]
The Nature reassessment's data cutoff (2020) and its publication year (2026) are six years apart.
- [11]
The Nature study said projected rises in ocean temperatures and other pressures "primarily determined when and where, rather than if, conditions will become unviable for corals."
- [12]
"When they hit their threshold the collapse of reefs in that region could be precipitous and we don't know if that is five, 15 or 30 years into the future, or maybe this year with the super El Niño ramping up?" said Obura.
- [13]
"It is entirely possible that reassessing the status of corals just after this coming El Niño may show them to have crossed the 50% mark of the proportion of species at elevated risk of extinction," said Obura.
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Sources
1 independent publisher whose own reporting we read for this story.
- phys.orgEl Niño a 'terrifying' threat to coral reefs: UN biodiversity expert
1 article · October 15, 2026
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