Intervention could buy ailing Great Barrier Reef 20 years

Brisbane, Australia: The use of experimental "cloud brightening" technologies and the introduction of heat-tolerant corals could help delay the Great Barrier Reef's climate-change-fueled decline by up to 20 years, according to Australian scientists on Thursday.

According to a report published in the peer-reviewed journal Royal Society Open Science, the reef will experience "precipitous decreases" in coral cover over the next five decades due to "intense pressure" from climate change.

Climate change is triggering underwater heatwaves, stronger cyclones, and floods, both of which are harming the reef's health.

"Coral reefs are some of the most climate-vulnerable ecosystems on Earth," lead author Scott Condie told AFP.

"The model projections suggest that coral cover on the Great Barrier Reef could fall below 10 percent within 20 years."

However, aggressive human efforts combined with "solid global climate action," according to Condie, a senior research scientist at the government's science agency CSIRO, could delay the rate of decline.

According to separate studies, the Great Barrier Reef has already experienced three mass coral bleaching events in five years and has lost half of its corals since 1995 as ocean temperatures have risen.

Scientists predict that up to 90% of all current coral reefs will disappear over the next 20-25 years. The bulk of the current reef reefs would be unsuitable for them by 2045 due to ocean pollution and climate change.

Whereas there is no question about the adverse effects of emission-driven emissions on marine life in general, the results indicate that coral reefs are most at risk.

Fast forward to 2100, and the scene of the coral reef habitat is “quite grim,” according to biogeographer Renee Setter of the University of Hawaii Manoa.

New research presented at Ocean Sciences Meeting 2020 by the University of Hawaii Manoa revealed these alarming projections.  

Cloud brightening

Condie and his co-authors simulated the possible effects of measures such as "cloud brightening," which was first tested on the reef by scientists last year.

The technology releases salt crystals into the atmosphere, causing clouds to reflect more sunlight and thereby cool the waters around the reef.

They also devised more stringent controls for the predatory crown-of-thorns starfish, which eat corals and proliferate when bleaching causes larger fish to flee an environment.

"The results suggest that combinations of interventions may delay the decline of the Great Barrier Reef by two decades or more," Condie said.

He said there was "clear urgency" to act but acknowledged that the scale of the work required was "much larger than anything that has previously been deployed on coral reefs".

"Any large-scale interventions would require a major financial investment and need to be acceptable to local communities," he added.

The modeling predicts that global temperatures would not rise above 1.8 degrees Celsius by 2100, which would necessitate governments sticking to their Paris climate agreement commitments.

The Australian government, which has defied calls to commit to a net-zero-emissions target by 2050, has reduced the reef's long-term outlook to "very low."

Aside from its incalculable natural, science, and environmental importance, the 2,300-kilometer (1,400-mile) reef was projected to be worth $4 billion in tourism revenue to the Australian economy prior to the coronavirus pandemic.

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