GCRMN finds a 9.5 per cent drop in global hard coral cover
GCRMN released a new status report on Monday with the International Coral Reef Initiative. Comparing 2020-24 with 1980-2009, it finds a 9.5 per cent decline in global hard coral cover, and in Australia cover fell from 30.2 per cent to 26.8 per cent. Manuel Gonzalez Rivero says bleaching has roughly doubled in frequency, so reefs no longer get the recovery time they need. Reefs cover under 1 per cent of the ocean floor and support more than 25 per cent of marine life.
Science··Midday
Hard coral cover fell 9.5 per cent from the GCRMN 1980-2009 reference
GCRMN released its new status report on Monday as a joint product with the International Coral Reef Initiative. The Australian Institute of Marine Science announced the Australian findings; lead author Manuel Gonzalez Rivero is based there. Comparing 2020-24 with a 1980-2009 reference period, the report finds a 9.5 per cent decline in global hard coral cover. In Australia, cover fell from 30.2 per cent to 26.8 per cent, a relative decline of 10.9 per cent. GCRMN said global coral cover sits well below normal levels and risks irreversible decline. Cover had held relatively steady for 40 years before a steep change began in 2010.[1], [2]
Bleaching frequency, Manuel Gonzalez Rivero said, has roughly doubled
Lead author Manuel Gonzalez Rivero of the Australian Institute of Marine Science said corals can recover if given enough time, but the frequency of bleaching events has roughly doubled, so that time is no longer there. Corals bleach by expelling the algae that live in their tissues. They have not died, but without the algae they are exposed to starvation and disease and need a stretch of cooler water before they can return. In 2023 that bleaching reached 77 per cent of the world's reef areas. The institute puts the Australian decline down to climate-driven heat stress, mass bleaching, cyclones and crown-of-thorns starfish outbreaks. Gonzalez Rivero said another such event is very likely this year given elevated temperatures worldwide.[1], [2]
Sharp declines hit Pilbara and the southern Great Barrier Reef
Reefs cover less than 1 per cent of the ocean floor and support more than 25 per cent of marine life. Scott Reef recovered after the 2016 bleaching. The southern Great Barrier Reef and the Pilbara region of Western Australia saw sharp declines through a run of disturbances. The effects of the fourth global bleaching event of 2024-25 have not been fully assessed. Monitoring is uneven, with gaps across northern and northwestern Australian reefs.[1], [2]
