‘Wake-up call to humanity’: research shows the Great Barrier Reef is the hottest it’s been in 400 years
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Wednesday, August 7, 2024
But repeated mass coral bleachings, driven by high ocean temperatures, are threatening the survival of coral colonies which are the backbone of the reef.
Key Points:
- But repeated mass coral bleachings, driven by high ocean temperatures, are threatening the survival of coral colonies which are the backbone of the reef.
- Our study, published today in Nature, provides a new long-term picture of the ocean surface temperatures driving coral bleaching.
- The results are sobering confirmation that global warming – caused by human activities – will continue to damage the Great Barrier Reef.
One-of-a-kind ecosystem
- However, mass coral bleaching over the past three decades has had serious impacts on the reef.
- Bleaching occurs when corals become so heat-stressed they eject the tiny organisms living inside their tissues.
- The Great Barrier Reef has suffered five mass bleaching events in the past nine summers.
A 400-year-old story
- As corals grow, the chemistry of their skeleton reflects the ocean conditions at the time – including its temperature.
- In particular, large boulder-shaped corals, known as Porites, can live for centuries and are excellent recorders of the past.
- Our study sought to understand how surface temperatures in the Coral Sea, which includes the reef, have varied over the past four centuries.
Humans are undoubtedly to blame
- Without human influence, Coral Sea surface temperatures during January–March remain relatively constant since 1900.
- Add in the human impacts, and the region warms steadily in the early 1900s, then rapidly after the 1960s.
- Recent climate projections put us on a path to intensified warming, even when accounting for international commitments to reduce emissions.
