Two-thirds of the Great Barrier Reefs have the largest cover in 36 years, the new report says.
Two-thirds of Australia’s Great Barrier Reef shows its largest coral cover in 36 years, according to an official long-term monitoring program, but the reef still vulnerable for mass bleaching more and more frequently.
The recovery in the Central and Northern regions of the United Nations Educational, Scientific and Cultural Organization or the UNESCO World Heritage-listed coral reef contrasts with the southern region, where the class is lost. coral cover due to an outbreak of thorny starfish, the Australian Institute of Marine Science (AIMS) said in its annual report on Thursday.
“What we are seeing is that the Great Barrier Reef is still a resilient system. It remains resilient to those disturbances,” AIMS monitoring program chief Mike Emslie told Reuters news agency.
“But what’s worrying is that the frequency of these disturbance events is increasing, especially those of mass coral bleaching,” he said.
However, scientists warn that the reef is still exposed to ocean warming.
Paul Hardisty, Executive Director of the Australian Institute of Marine Science, told Al Jazeera.
“Nothing could be more true. And the reason is that this reef in any given year has the potential to be devastating. bleach events caused not by particular solar radiation, but by warming oceans and oceanic heatwaves caused by climate change,” he said.
The publication of the report by UNESCO consider whether the Great Barrier Reef should be listed as “in danger”, following a visit by UNESCO experts in March.
The meeting of the World Heritage Committee where the fate of the reef is on the agenda was to be held in Russia in June but has been postponed.
In an important measure of reef health, the AIMS identifies hard coral cover more than 30% as highly valuable, based on long-term surveys of the reef.
In the Northern region, average hard coral cover increases to 36% in 2022 from a low of 13% in 2017, while in the Central region, hard coral cover increases to 33% from low 12% in 2019 – the highest recorded for both regions since the institute began monitoring the reef in 1985.
However, in the southern region, which typically has higher hard coral cover than the other two regions, cover has fallen to 34% in 2022 from 38% a year earlier.
The recovery comes after the fourth mass bleaching in seven years and the first during the La Nina event, which typically brings cooler temperatures. The institute says that, while widespread, bleaching in 2020 and 2022 is not as damaging as in 2016 and 2017.
On the other hand, mantle growth is driven by Acropora corals, which AIMS says are particularly vulnerable to waves, heat stress and thorny starfish.
“We are really in uncharted waters when it comes to the effects of bleaching and what it means to move forward. But to this day, it’s still a great place,” said Emslie.