For the third time in just five years the Great Barrier Reef is suffering coral bleaching. Even if bleaching can occur naturally and corals can recover, there are limits to how much even the greatest of them all can take.
During the last two weeks of March professor Terry Hughes at the ARC Centre of Excellence for Coral Reef Studies, James Cook University, Queensland studied one of the world’s most incredible natural phenomena. He and his team analysed 1,036 reefs from the air and what they saw was devastating.
International news media like New York Times, CNN, The Guardian and BBC reported the sad news.
The first massive bleaching was registered in 1998. That year the ocean surface temperature was the highest since recording startet in 1990. Bleaching occurs when the temperature increases more than normal. Reefs normally recovers from light bleaching after a few weeks. But when it is hit by severe, widespread bleaching over time it parts of it may die.
In 2016 half of the green part of the Northern Great Barrier Reef died. It happened again in 2017. Then it was the central part that was hit hard.
What has happened since the last bleaching?
For the first time bleaching has hit the entire reef; the Northern, Central and Southern parts of the reef.
Hughes explains in the report that warmer summers cause bleaching, even without the El Niño effect. Only in 1998 and 2016 bleaching coincided with El Niño.
More frequent bleaching means that the coral reefs don’t have time to recover. This is what happened in 2016 and 2017.
Coral bleaching is when the zooxanthellae algae is expelled by the coral. This happens when corals get stressed for instance when it gets too hot. Change in nutrition and sunlight may also cause this stress. The coral fades in color and if the temperature stays high, the algae won’t come back and the coral dies. One third of the Great Barrier Reef was damaged due to the mass bleaching in 2016-2017.
Also read: Wild fires in Australia and coral death
The Great Barrier Reef is the Earth’s largest living marine structure. It has countless ecosystems and a vast biodiversity. Globally, coral reefs represent an economic value of some 36 billion dollars every year.
It will die in a warm world
The Australian Climate Council published in July 2018 a report of the 2016-2017 bleaching. It found that the damage was even worse than what was reported initially. The report also warned that from 2030 this phenomenon is likely to happen every second year. This means that the entire Great Barrier Reef is about to die completely.
The report also warns that unless we reach the 1.5 degrees target, the reef has little chances to survive. By 2 degrees increase it is likely that all tropical coral reefs will collapse.
Although mass bleaching is not something new, it only occurred every 27 years on average before the climate change effects kicked in. Today is happens every 6 years. And even if the Great Barrier Reef does recover it will never get back its glorious days.
The US National Oceanic and Atmospheric Administration (NOAA) is monitoring the world’s coral reefs. Lot’s of data and illustrations there giving you the state of the reefs.
Also read: Another blow for the US oceanic research
Cover image: Greenpeace sounded the alarm already in 2012 to get the world’s attention to the Great Barrier Reef. Gladstone, Australia, March 7. 2012. Photo: Greenpeace via Getty Images.
