Coral bleaching on Great Barrier Reef worse than first thought

New Delhi: Scientists have warned on Monday that coral bleaching on Australia`s Great Barrier Reef is even worse than first thought, adding that the impact will accelerate unless global greenhouse gas emissions are cut.

Initial aerial and in-water surveys confirmed that about 29% of shallow water corals died from bleaching during 2016, up from the previous estimate of 22%, with the reef currently experiencing an unprecedented second straight year of bleaching.

"The amount of coral that died from bleaching in 2016 is up from our original estimates and, at this stage, although reports are still being finalised, it`s expected we`ll also see an overall further coral cover decline by the end of 2017,” Great Barrier Reef Marine Park Authority (GBRMPA) chairman Russell Reichelt said.

The 2,300-kilometre (1,400-mile) World Heritage-listed reef suffered its most severe bleaching on record last year due to warming sea temperatures during March and April.

Bleaching was also found in corals beyond depths divers typically survey, but mortality could not be systematically assessed.

The most severely impacted region was an area north of the popular tourist town Port Douglas, where an estimated 70 percent of shallow water corals have died.

Cairns and Townsville, also hugely popular tourist destinations, are among the regions hardest-hit from the 2017 bleaching event, although southern parts of the natural wonder escaped the worst.

Corals can recover if the water temperature drops and the algae are able to recolonise them, but it can take a decade.

The GBRMPA hosted a summit last week of more than 70 of the world`s leading marine experts to work on a blueprint on how best to respond to the threats.

Among options explored was developing coral nurseries, strategies to boost culling of crown-of-thorns starfish, expanding monitoring systems and identifying priority sites for coral restoration.

Key to the talks was the need to slash greenhouse gas emissions to prevent warming sea temperatures.

"The Great Barrier Reef is a large and resilient system that`s previously shown its capacity to bounce back, however the current changes are undermining the resilience of the reef," said Reichelt.

Summit participants voiced their strong concern about the need for global action to reduce greenhouse gas emissions, the driver of climate change.

Reichelt added the storm impacted a quarter of the reef but a complete picture for 2017 would not be available until next year.

(With AFP inputs)