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“Extreme bleaching”

The Great Barrier Reef is dying at a rate not expected for another 30 years

The Great Barrier Reef is dying at a rate not expected for another 30 years

Scientists didn’t expect such dire conditions for at least another 30 years, but due to climate change, one of the world’s most spectacular natural wonders is dying at a much faster rate than previously thought.

“We didn’t expect to see this level of destruction to the Great Barrier Reef for another 30 years,” Terry Hughes, director of an Australian government-funded center for coral reef studies at James Cook University, said. “In the north, I saw hundreds of reefs — literally two-thirds of the reefs were dying and are now dead.”

New research published Thursday shows just how much damage Australia’s coral reefs, home to a dazzling array of marine life, have incurred due to warmer waters. Huge swathes of reefs were devastated last year in the worst mass bleaching incident on record, with up to 83 percent of corals dying in certain areas, such as a long stretch north of Port Douglas. This was the third major coral bleaching event since 1998, but the damage being done to these living organisms is increasing dramatically.

The facts speak for themselves. In the 1998 and 2002 events, less than 10 percent of the Great Barrier Reef was subject to “extreme bleaching.” In 2016 that figure shot up to a devastating 50 percent.

Last week it was confirmed that another mass bleaching event is underway, making it the first time such events have happened in consecutive years. The National Coral Bleaching Taskforce will assess the true scale of the damage in the next three weeks. Prof. Morgan Pratchett, also from James Cook University, told the BBC that the “window of opportunity” to stop the impact of emissions was closing.

Here’s what you need to know:

  • The report, entitled ‘Global Warming and Recurrent Bleaching of Corals,’ was authored by 46 scientists who studied the 2016 mass bleaching event on Australian reefs and compared it to the other two recorded incidents, one in 1998 and another in 2002.
  • The damage was not uniform, with the southern section of the reef avoiding damage completely, while more northerly parts lost up to 83 percent of their coral.
  • Bleaching occurs when the microscopic algae that live on the coral — and give them their spectacular color — leave. This happens when coral gets “stressed” as a result of a change in their environment. While this can be caused by overfishing or the impact of humans, by far the biggest cause is the increase in water temperature. Once the algae leave, the coral loses its color or becomes “bleached,” and is more susceptible to disease.
  • The Great Barrier Reef is the world’s largest reef system, composed of some 2,900 individual reefs. It stretches for over 1,600 miles along the eastern coast of Australia and is so big it can be seen from space. As well as being home to more than 400 types of hard coral, the World Heritage site sustains an ecosystem comprised of over 1,500 species of fish while 30 species of whales, dolphins, and porpoises have been recorded there.
  • When it comes to climate change’s impact on the Great Barrier Reef, the Australian government has by-and-large ignored the problem. In its Reef 2050 plan the government outlines measures to improve water quality, update fishing and shipping regulations, protect wildlife and manage land use — but by and large fails to address climate change.
  • “Globally, reefs as we knew them in the 1990s, I don’t think those will come back,” Sean Connolly, an associate professor at James Cook University, said. “I don’t think we’ll see reefs with that very high coral cover and complexity in the future. The question is how degraded they’ll be.”
  • Just last week, the Great Barrier Reef Marine Park Authority announced that another mass bleaching event is underway — the first time bleaching events have occurred in back-to-back years. Hughes, who led the research into last year’s event, is due to embark Thursday on an aerial survey to confirm the extent of this year’s mass bleaching event.

Cover: (REUTERS/David Gray)

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