Scientists mobilise as bleaching returns to Great Barrier Reef

The Great Barrier Reef has been hit by mass bleaching for the second year in a row

Scientists race to prevent wipeout of coral reefs

Coral bleaching is caused by rising water temperatures which is exacerbated by man-made climate change. Huge swathes of reefs were devastated a year ago 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.

"Recovery for long-lived species requires the sustained absence of another severe bleaching event (or other significant disturbance), which is no longer realistic while global temperatures continue to rise", write the authors.

The reef - a vast collection of thousands of smaller coral reefs stretching from the northern tip of Queensland to the state's southern city of Bundaberg - was given World Heritage status in 1981.

Professor Hughes said the observed distribution can be explained by the spatial patterns of ocean warming.

Extensive stand of severely bleached coral at Lisianski Island in the Papahanaumokuakea Marine National Monument in Hawaii, documented during an August 2014 NOAA research mission.

Bleaching is primarily caused by prolonged exposure to high sea surface temperatures (SSTs). If the coral reefs die, we would lose some of the richest and most colorful life forms in the ocean. Terry Hughes (ARC Centre of Excellence for Coral Reef Studies). New research published this month shows that stopping forthcoming "mass bleaching events" will only realistically be achieved by taking drastic climate change measures worldwide, the Guardian reported Wednesday. In longer and warmer stances, the coral has lower chances of survival.

"Globally what's been happening is the number of these bleaching events is going up and up, and the time interval between them is shrinking".

This finding calls into question whether the Australian government's Reef 2050 Long-Term Sustainability Plan, which focuses largely on water quality and reducing the impact of ports and shipping on the reef, will do much to mitigate large-scale bleaching.

The aerial survey showed that the Great Barrier Reef is experiencing widespread coral bleaching for the second year in a row, indicating that water temperatures remained too warm to allow corals to recover from last year's bleaching.

The Great Barrier Reef's hundreds of islands and 2,900 individual reefs stretch for nearly 1,500 miles along the coast of North East coast of Australia.

And so one of the most delicate ecosystems on the planet begins to give up the ghost, with the Great Barrier Reef in decline.

The team also looked at the impacts of improved water quality and protecting the reefs from fishing.

Local management of fishing pressure and water quality provided little protection - suggesting a curb in global warming will be needed to secure a viable future for the world's most spectacular reef system.

The paper "Global warming and recurrent mass bleaching of corals", by 46 co-authors, appears today in the journal Nature. He says that there's a window of opportunity, but the world's running out of time.

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