Half of The Great Barrier Reef’s Coral Lost
(October 15, 2012) In just 27 years – a mere moment on our planet’s life-clock, Australia’s Great Barrier Reef has lost half of its coral cover; an area equal to the size of Germany. Three separate culprits have been given credit for the decline, while all three are said to be related to climate change and global warming.
This was revealed in a study from the Australian Institute of Marine Science (AIMS), published earlier this month in the US journal the Proceedings of the National Academy of Sciences.
The following article was published at the same time in Australian Geographic. The following are excerpts.
THE GREAT BARRIER REEF is one of the planet’s most famous natural wonders, stretching across 348,000sq.km and comprised of more than 2900 separate reefs. But disturbing new research reveals it has lost half its coral cover since 1985.
“Coral cover on the GBR is consistently declining, and without intervention, it will likely fall to 5 to 10 per cent within the next 10 years,” say the authors of the report. “Without intervention, the GBR may lose the biodiversity and ecological integrity for which it was listed as a World Heritage Area.”
The study is based on data collected by a reef monitoring program that began in 1985 and looked at 214 reefs in 2,258 separate surveys. It showed a 50.7 per cent decline in reef cover between 1985 and 2012.
The authors of the report cite three major causes for the decline: tropical cyclones caused 48 per cent of the loss, coral predation from crown-of-thorns starfish (Acanthaster planci) led to another 42 per cent, and coral bleaching was responsible for the final 10 per cent.
“The shocking thing about the research is that this downward turn in coral cover has occurred in the world’s most sophisticated marine management park,” says Professor Ove Hoegh-Guldberg, who heads up the Coral Reef Ecosystems Lab at the University of Queensland. “We’re not talking about reefs that have been under extreme environmental stresses, such as those in Southeast Asia; it’s happening in this well-managed marine park and it’s happening very rapidly.”
All three of the drivers causing the coral decline are related to climate, says Ove, who was not involved in the study. Bleaching is caused by extreme heat events and rising sea temperatures, and there’s growing evidence to suggest warmer seas are leading to more intense tropical storms and more intense flooding of the sort we saw two years ago.
Ove says that a global reduction in carbon dioxide emissions is the long-term key to preventing bleaching and reducing the intensity and volume of storm systems. “What we do in the coming decade will ultimately determine the future of ecosystems like this one,” he adds.
Read more: Australian Geographic