Great Barrier Reef coral reproduction down 89% due to global warming

Coral reproduction on the Great Barrier Reef has fallen 89 per cent after repeated bleaching from global warming in 2016 and 2017, finds Australian researchers.

The damage caused to the Great Barrier Reef by global warming has compromised the capacity of its corals to recover, according to a new study published in Nature.

“Dead corals don’t make babies,” lead author Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University (JCU), said in a statement. “The number of new corals settling on the Great Barrier Reef declined by 89 per cent following the unprecedented loss of adult corals from global warming in 2016 and 2017.”

The study measured how many adult corals survived along the length of the Great Barrier Reef following extreme heat stress, and how many new corals they produced to replenish the reef in 2018.

“Our study shows that reef resilience is now severely compromised by global warming,” said co-author Professor Andrew Baird. “The mix of baby coral species has shifted, and that in turn will affect the future mix of adults, as a slower than normal recovery unfolds over the next decade or longer.”

According to Hughes, the areas that lost the moral corals experienced the greatest declines in replenishment. He expects coral recruitment to gradually recover over the next five to ten years as surviving corals grow and reach sexual maturity, “assuming of course that we don’t see another mass bleaching event in the coming decades”.

The Great Barrier Reef has experienced four mass bleaching events since 1998 due to global warming. “It’s highly unlikely that we could escape a fifth or sixth event in the coming decade,” said co-author Professor Morgan Pratchett.

“There’s only one way to fix this problem,” said Hughes, “and that’s to tackle the root cause of global heating by reducing net greenhouse gas emissions to zero as quickly as possible.”

Image credit: U.S. Geological Survey

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