Great Barrier Reef in steep decline
Climate change, destructive starfish damaging ecosystem
SINGAPORE— The world’s largest coral reef — under threat from Australia’s surging coal and gas shipments, climate change and a destructive starfish — is declining faster than ever and coral cover could fall to just 5 per cent in the next decade, a study shows.
Researchers from AIMS, the Australian Institute of Marine Science, say the Great Barrier Reef has lost half of its coral in little more than a generation. And the pace of damage has picked up since 2006.
Globally, reefs are being assailed by myriad threats, particularly rising sea temperatures, increased ocean acidity and more powerful storms. But the threat to the Great Barrier Reef is even more pronounced, the AIMS study published on Tuesday found.
“In terms of geographic scale and the extent of the decline, it is un- precedented anywhere in the world,” said AIMS chief John Gunn.
AIMS scientists studied data from more than 200 individual reefs off the Queensland coast covering the period 1985-2012. They found cyclone damage caused nearly half the losses, crown-of-thorns starfish more than 40 per cent and coral bleaching from spikes in sea tem- peratures 10 per cent. The starfish are native and prey on the reefs. But plagues are occurring much more frequently. Ordinarily, reefs can recover with- in 10 to 20 years from storms, bleachings or starfish attacks but climate change impacts slow this down. Rising ocean acidification caused by seas absorbing more carbon dioxide is disrupting the ability of corals to build their calcium carbonate structures. Hotter seas stress corals still further.
Greens say the 2,000-kilometrelong reef ecosystem, the centrepiece of a multi-billion-dollar tourism industry, also faces a growing threat from shipping driven by the planned expansion of coal and liquefied natural gas projects. Those concerns have put pressure on the authorities to figure out how to protect the fragile reef.
The researchers say the pace of coral loss has increased since 2006 and if the trend continues, coral cover could halve again by 2022, with the southern and central areas most affected.
“Coral cover on the reef is consistently declining, and without intervention, it will likely fall to 5 to 10 per cent within the next 10 years,” researchers write in the study published in the journal Proceedings of the National Academy of Sciences.