NOAA Warns El Niño Could Trigger Fifth Global Coral Bleaching Event
NOAA released an updated coral-bleaching outlook on Tuesday, June 2, warning that the expected El Niño could drive widespread bleaching across the northern Pacific and U.S. tropical waters.[1]
The outlook flags high bleaching risk from June through September 2026 in the northern Pacific, including Hawaii, and warns heat could affect reefs near Florida and across the Caribbean.[1] NOAA said every strong El Niño since 1998 has coincided with global bleaching, and that sea-surface temperatures now exceed those seen during the first mass event.[1]
A 2024-2025 global bleaching episode affected about 84% of coral reefs worldwide, and NOAA says a new El Niño-driven event would be the fifth recorded global bleaching event.[1] To help reefs survive, NOAA is investigating coral heat tolerance and resilience to guide restoration and identify reefs that better withstand high temperatures.[1]
NOAA will monitor heat stress and update its forecasts through the June through September window to help managers and conservationists plan responses.[1]
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📌 Key Facts
- On Tuesday, June 2, 2026, NOAA released an updated coral bleaching outlook tied to an expected El Niño.
- The outlook warns of high bleaching risk between June and September 2026 in the northern Pacific, including Hawaii, and potentially around Florida and the Caribbean.
- If realized, this would mark the fifth recorded global coral bleaching event, following a 2024-2025 episode that affected 84% of reefs worldwide.
- NOAA notes every strong El Niño since 1998 has coincided with global bleaching and that sea surface temperatures now exceed levels seen during the first mass event.
- NOAA is investigating coral heat tolerance and resilience to improve restoration strategies and identify reefs that better withstand high temperatures.
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