Subel Bhandari -
Australia’s Great Barrier Reef can only survive if steps to cut global warming are taken urgently, according to new scientific research.
The study, released in the journal Nature on Thursday, shows that protecting reefs from fishing and improving water quality does not prevent bleaching of coral when major water temperature increases occur. It also said bleaching events should no longer be studied individually, because they are a threat to the reef’s survival.
“Global warming is the number one threat to the Reef,” co-author David Wachenfeld said. Last year, the reef — the largest coral structure on earth — saw unprecedented bleaching due to a temporary rise in sea temperatures of up to 4 degrees Celsius.
It caused 90 per cent of the reef’s coral to bleach, the worst in recorded history, and killed more than 20 per cent of the reef’s coral. In the north, two thirds of the coral died. “The severity of the 2016 bleaching was off the chart,” Terry Hughes,a professor and head of ARC Centre of Excellence for Coral Reef Studies, said. “It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four.”
The scientific research found that the cumulative, superimposed footprint of the three mass bleaching events has now encompassed virtually all of the Great Barrier Reef, the statement said.
Hughes also said there was no evidence, looking at the past exposure, to suggest that “bleaching makes coral reefs any tougher.”
Last week the Australian government’s marine park authority said the reef was experiencing mass coral bleaching for the second consecutive year, which was the first time it did not get a few years between bleaching events to recover. Scientists say it usually takes five years for a reef to recover from a single bleaching event. Coral bleaching is caused by a die-off of the living organisms, or algae, inside the coral. It can be triggered by small changes in environmental conditions, such as a rise in sea temperature.
The loss of the colourful algae then causes the coral to turn white. The reef also faces losing UNESCO World Heritage Site status which it gained in 1981. A UN committee is set to give its verdict by July on whether to categorise the region as “in danger.” — dpa
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