Great Barrier Reef

Australia confirms new mass bleaching event

It is the fourth time in six years that such severe and widespread damage - caused by warm sea temperatures - has been detected.

Only two mass bleaching events had ever been recorded until 2016.

Scientists say urgent action on climate change is needed if the world's largest reef system is to survive.

There are particular concerns that this bleaching event has occurred in the same year as a La Niña weather phenomenon. Typically in Australia, a La Niña brings cooler temperatures.

Great Barrier Reef: Two-thirds damaged in 'unprecedented' bleaching

The bleaching - or loss of algae - affects a 1,500km (932 miles) area of the reef, according to scientists.

The latest damage is concentrated in the middle section, whereas last year's bleaching hit mainly the north.

Experts fear the proximity of the two events will give damaged coral little chance to recover.

Prof Terry Hughes, from James Cook University, said governments must urgently address climate change.

Great Barrier Reef survival relies on halting warming, study warns

Attempting to stop coral bleaching through any other method will not be sufficient, according to scientists.

The research, published in the journal Nature, said bleaching events should no longer be studied individually, but as threats to the reef's survival.

The bleaching - or loss of algae - in 2016 was the worst on record.

Great Barrier Reef gripped by another mass bleaching

The Great Barrier Reef has been closely monitored for the past few years due to bleaching concerns. 

The first survey for 2017 was conducted on Thursday by the Great Barrier Reef Marine Park Authority, over the area between Cairns and Townsville in northern Queensland.

The agency's David Wachenfeld said that had given him enough information to "regrettably" confirm another mass bleaching.

"We also have quite a few reports through our early warning system, the eye on the reef program," Dr Wachenfeld said.

Protecting reefs from extinction

It is the first worldwide initiative aimed at protecting reefs from extinction and to date, funding is coming from philanthropic organisations, not governments.

Scientists estimate 90 per cent of the world's coral reefs will disappear in the next 35 years due to coral bleaching induced by global warming, pollution and over-development.

Great Barrier Reef suffered worst bleaching on record in 2016, report finds

Some 67% of corals died in the reef's worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.

The situation was better in the central section, where 6% perished, while the southern reef is in good health.

But scientists warn recovery could be difficult if climate change continues.

Coral bleaching happens when water temperatures rise for a sustained period of time.