06/04/2026
NOAA experts have determined that the fourth global coral bleaching event likely concluded in mid-2025 following unprecedented heat stress across the world’s coral reefs.
Between early 2023 and mid-2025, bleaching-level heat stress impacted 84% of global coral reef areas across the Pacific, Atlantic and Indian Oceans, with mass bleaching documented in at least 83 countries and territories.
Researchers are continuing to study coral reefs that showed signs of resilience despite prolonged heat exposure, helping improve our understanding of coral heat tolerance and inform future restoration strategies.
While the global event appears to have subsided, ocean temperatures remain elevated compared to previous decades, and NOAA is forecasting continued bleaching risks for this summer and fall in the Northern Hemisphere.
Learn more: bit.ly/4x5yzZq
NOAA Coral Reef Conservation Program