​Great Barrier Reef: Over 90% Bleached Due To Climate Change

Great Barrier Reef
Author: John LesterBy:
Staff Reporter
Apr. 21, 2016

The Great Barrier Reef is over 90% bleached has become an environmental devastation on the largest coral ecosystems on Earth, and scientists say its from man made climate change. Australia’s National Coral Bleaching Task Force has surveyed 911 coral reefs by air, and found at least some bleaching of the vast majority of them.

The Great Barrier Reef bleaching was the worst in the reef’s remote northern sector - where virtually no reefs escaped it, National Geographic reports. The scientists also reported that based on diving surveys of the northern reef, they already are seeing nearly 50 percent coral death.

“Between 60 and 100 percent of corals are severely bleached on 316 reefs, nearly all in the northern half of the Reef,” Prof. Terry Hughes, head of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, said in a statement to the news media. He led the Great Barrier Reef research.

The severe Great Barrier Reef bleaching means that corals could die, depending on how long they are subject to these conditions, Climate Central noted. “The fact that the most severely affected regions are those that are remote and hence otherwise in good shape, means that a lot of prime reef is being devastated,” said Nancy Knowlton, Sant Chair for Marine Science at the Smithsonian Institution, in an email in response to the bleaching announcement. “One has to hope that these protected reefs are more resilient and better able to [recover], but it will be a lengthy process even so.”

Knowlton added that Hughes, who led the Great Barrier Reef research, is “NOT an alarmist.”

“This is, by far, the worst bleaching they’ve seen on the Great Barrier Reef,” said Mark Eakin, head of the National Oceanic and Atmospheric Administration’s Coral Reef Watch, which partners with the Australian National Coral Bleaching Taskforce. “Our climate model-based Four Month Bleaching Outlook was predicting that severe bleaching was likely for the [Great Barrier Reef] back in December. Unfortunately, we were right and much of the reef has bleached, especially in the north.”

Responding to the news Wednesday, the Australian government’s Great Barrier Reef Marine Park Authority put out a statement from its chairman Russell Reichelt. “While the data is incomplete, it is clear there will be an impact on coral abundance because of bleaching-induced mortality, mainly in the far north,” the statement said in part.

Coral bleaching occurs when corals are stressed by unusually high water temperatures, or from other causes, The Independent reported. When this happens, symbiotic algae, called zooxanthellae, leave the corals’ bodies. This changes their color to white and can also in effect starve them of nutrients. If the Great Barrier Reef bleaching continues for too long, the corals die.

There already have been reports of mass coral death around the Pacific atoll of Kiribati this year - and widespread coral bleaching worldwide, a phenomenon that scientists attribute to a strong El Niño event surfing atop a general climate warming trend.

Tourism involving the Great Barrier Reef is worth $5 billion annually, and accounts for close to 70,000 jobs, according to the news release from the Australian National Coral Bleaching Taskforce.

Recently, journalist Chelsea Harvey reported that some scientists think the Great Barrier Reef bleaching this extensive could be a sign of “dangerous” climate change caused by humans.

The 1992 United Nations Framework Convention on Climate Change, just after saying that countries should avoid such dangerous interference with the climate, adds that atmospheric greenhouse gas levels should be stabilized “within a time frame sufficient to allow ecosystems to adapt naturally to climate change.”

Indeed, recent research suggests that Great Barrier Reef corals have a mechanism to protect them if waters warm up beyond normal, but then cool down again before a second warming that crosses the bleaching threshold. However, as oceans continue to warm, it found, that pattern will be less prevalent, meaning that corals will be less able to cope.

Despite the Great Barrier Reef bleaching event, USA Today said that past global coral erosion have occurred in 1998 and 2010. In 1998, scientists ultimately documented through much follow-up research that 16 percent of the world’s corals died in that event. The full toll of the current global bleaching event has not yet been determined.

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