Habitat Destruction: Great Barrier Reef Bleaching

The Great Barrier Reef experienced consecutive mass coral bleaching in 2024 and 2025, only the second back-to-back bleaching sequence on record after 2016–2017. AIMS says the 2024 event was the reef’s fifth mass bleaching since 2016 and part of the fourth global coral bleaching event, which NOAA and the International Coral Reef Initiative declared in April 2024 after it began in 2023. AIMS’ 2024/25 condition summary reports that the 2024 bleaching event had the largest spatial footprint ever recorded on the Great Barrier Reef, with high to extreme bleaching across the Northern, Central, and Southern regions, and that nearly 60% of reefs were exposed to heat stress levels associated with severe fully bleached corals. In 2025, the reef experienced its sixth mass bleaching since 2016; AIMS reported surveys across 281 reefs in the Torres Strait, the northern GBR, and parts of the central GBR, and found regional coral-cover declines of 14% to 30% versus 2024, with some reefs losing up to 70.8% of coral cover. NOAA’s global coral bleaching update says bleaching-level heat stress from 1 January 2023 to 30 September 2025 affected about 84.4% of the world’s coral reef area and that mass bleaching has been documented in at least 83 countries and territories. The latest AIMS annual summary for 2025/26 indicates some stabilization and slight recovery in 2026, but it also says impacts from the 2024–25 bleaching sequence remain significant.