Study Finds Coral Bleaching Along 98% Of Great Barrier Reef
A new report by James Cook University reveals the impacts of changes to coral bleaching along the Great Barrier Reef, the worlds largest coral reef system.
Published on Friday, the study found only two percent of the reefs underwater ecosystem had avoided bleaching since the first mass coral event back in 1998.
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Terry Hughes, lead author from the ARC Centre of Excellence for Coral Reef Studies, found that the increase in coral bleaching events, directly correlates to the frequency, intensity and size of marine heatwaves as a result of climate change.
"Five bouts of mass bleaching since 1998 have turned the Great Barrier Reef into a checkerboard of reefs with very different recent histories, ranging from two percent of reefs that have escaped bleaching altogether, to 80 percent that have now bleached severely at least once since 2016,".
A stress response due to overheating corals during heat waves, bleaching is when corals lose their colour and struggle to survive.
Scientists hope that the area least impacted by bleaching, known as Swain reefs in the southern section, could act as a refuge from bleaching, encouraging corals to survive and disperse larvae onto the damaged reef.
Published in the journal Current Biology the study also found areas “earmarked earlier as candidate refuges” had since experienced bleaching in a moderate capacity at least once.
“The world is now littered with former potential coral reef refuges that have since bleached,” Professor Hughes said.
The report also indicated that corals that have avoided being bleached for a long time, were more vulnerable to the effects of bleaching, while those that had previously been exposed to heatwaves were less susceptible to heat stress.
“The recovery driven by heat-sensitive coral is similar to the recovery in a forest after a fire. The most flammable grasses come back faster, which can push the transition of the area from fire-resistant forest to a fire-prone grassland,”
Ironically the study has been released just as the COP26 Climate Summit in Glasgow is steering world leaders to stand together on promises to reach net zero emissions by 2050, with calls to limit global warming to 1.5 degrees.
"If we can hold global warming to 1.5 degrees global average warming then I think we'll still have a vibrant Great Barrier Reef," Prof Hughes said.
Prone to floods, fires and cyclones, the damage done due to climate change in Australia, is no longer only a question of why, but when.
Not holding anything back, Professor Hughes said reefs would struggle to survive, even if pledges at the climate conference were met. But without trying, there would be devastating consequences.
"Action to curb climate change is crucial".
- Prof Terry Hughes
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