The Reef Snapshot: Summer 2024–25 (pdf), published today by the Great Barrier Reef Marine Park Authority, states:
Results of aerial surveys and in-water monitoring to date suggest the Reef has experienced widespread coral bleaching across the Far Northern and Northern regions of the Marine Park — mostly a result of prolonged exposure to higher-than-average water temperatures.
This event is the sixth since 2016 and, while less extensive than the coral bleaching event in 2023–24, it is the second time the Reef has experienced widespread bleaching events across consecutive summers.
Officially, Australia’s international treasure suffered mass coral bleaching in 1998, 2002, 2016, 2017, 2020, 2022 and 2024.
Mass bleaching has been monitored throughout the Great Barrier Reef since the 80s. There was certainly bleaching but not at the level seen in the years listed, and look how that frequency changed. I doubt it’s because we got better at documenting bleaching effects. The important thing is that bleaching to some degree is normal, but typically the population would have time to recover before the next event, and they would be localized. Large scale and every year doesn’t allow recovery.