Stretching for 2,300 kilometres along Australia’s boundless north-east coastline and clearly distinct from outer space, the world’s largest living organism has become the newest, and most certainly the biggest, victim of steadily warming oceans caused by climate change.
The Plight of The Great Barrier Reef
Guest post by Adam Blau
Panic is sweeping through the scientific community as the Great Barrier Reef, Australia’s national treasure and the world’s largest reef system, is facing unprecedented threats due to widespread coral bleaching. Damning evidence of the impact of climate change on the Great Barrier Reef is causing trepidation among scientists, researchers, local residents, tourism operators and the general public – as well as anyone who has been lucky enough to experience the dazzling colours and structures, incredible marine life and unmatched biodiversity of the Reef.
Home to 10 percent of the world’s fish population and an irreplaceable cog in the delicate balance of the planet’s ecosystem, there can be no surprise at the panic stirred by claims that half of the Great Barrier Reef has disappeared since 1980.
According to a 2012 report by the Australian Institute of Marine Scientists (AIMS), the Great Barrier Reef has lost more than 50.7 percent of reef cover in the last thirty years. At its current rate of demise, the reef may disappear by a further 5 to 10 percent in the next decade. Worse yet, in March of this year, the Great Barrier Reef Marine Park Authority (GBRMPA) sent shockwaves through the global community when it reported the full extent of coral bleaching in the Reef.
Dr Russell Reichelt, Chairman of GBRMPA said in a recent statement that though more surveys need to be undertaken to gauge the full impact of bleaching, the outcome does not look good.
“Unfortunately, the further north we go from Cooktown, the more coral mortality we’re finding… The corals in the remote far north of the Reef experienced extremely hot and still conditions this summer and were effectively bathed in warm water for months, creating heat stress that they could no longer cope with,” he said.
Bleaching is the most obvious sign of a troubled coral reef. Small but significant increases in sea temperature disrupt the delicate relationship between coral and the tiny marine algae thriving within their tissue. These algae supply the majority of energy that coral requires for growth and reproduction, but in times of thermal stress, coral organisms expel these algae particles and gradually lose colour and then health. If cooler temperatures don’t arrive, corals devolve into lifeless white skeletons, causing huge ripple effects to fish populations and reef tourism – imagine pulling a block out from the bottom from an intricate stack; it all topples.
According to aerial assessments conducted by Professor Terry Hughes and his team at the National Coral Bleaching Taskforce, up to 93 percent of the reef is experiencing bleaching.
“This has been the saddest research trip of my life,” said Professor Hughes. “Almost without exception, every reef we flew across showed consistently high levels of bleaching, from the reef slope right up onto the top of the reef.
“We flew for 4000km in the most pristine parts of the Great Barrier Reef and saw only four reefs that had no bleaching. The severity is much greater than in earlier bleaching events in 2002 or 1998,” he said.
While large-scale coral bleaching has been recorded several times, the University of Queensland Global Change Institute Director, Professor Ove Hoegh-Guldberg, who has studied the impact of climate change on coral for more than three decades, agrees that this current level is historically dire.
“From the tip of Cape York to the Whitsundays, the Great Barrier Reef in the east to the Kimberleys in the west and Sydney Harbor in the south, Australia’s corals are bleaching like never before.
“This is the worst coral bleaching episode in Australia’s history, with reports of coral dying in places that we thought would be protected from rising temperatures,” Hoegh-Guldberg said in a statement.
The warming oceans as described by Heogh-Guldberg predicates the three biggest reef killers: tropical cyclones, the parasitic Crown-of-thorns starfish and coral bleaching. While the Great Barrier Reef has proven in the past to be resistant to these elements, able to naturally regenerate as cooler weather arrives and the starfish controlled, changes to ocean conditions since the 1980s have occurred so rapidly and to such extreme levels that we may be on the precipice of disaster.
From burning fossil fuels at historically high levels to the massive increases in population and industry along the Queensland coast, we are now witnessing the true impact of humanity’s interaction with the reef. Thirty percent of the carbon dioxide we produce is absorbed by the ocean. Coupled with El Nino events, human-induced climate change is driving record-breaking temperatures worldwide, bringing the hottest year ever recorded in 2015 and more of the same in 2016. If the trends continue, one of the world’s wonders may be irrevocably damaged.
But there is still hope. In reaction to the crisis, GBRMPA has signalled Level 3 on the health of the Great Barrier Reef, the highest level of its coral bleaching response plan. Furthermore, a 16-member partnership group between local and federal governments, Traditional Owners, key industry organisations, scientists and interest groups have prioritised conservation in the Great Barrier Reef 2050 Sustainability Plan. This proactivity will go some way to protecting the Reef’s future, a sentiment reinforced by Professor Heogh-Guldberg.
“We will definitely see a degraded reef,” he told website IFLScience, “however, if the world stops pumping out more CO2, temperatures will stabilize. Corals will be rare, but if we have not wiped them out entirely, they will eventually come back.”
Near-universal consensus maintains that if the Reef is to survive, drastic action both locally and internationally must be taken to limit climate change. The Great Barrier Reef can be seen as the barometer of our world’s oceans; clearly, their health and vitality have arrived at a crucial tipping point. Encouragingly, just weeks ago the Paris Accords were signed off by a majority of state representatives, vowing to transform the fossil-fuel driven economy and drastically slow the rate of global warming. These pledges, it seems, can’t come soon enough.
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