Half of the Great Barrier Reef Has Died Since 2016

Scientists have known that Australia’s iconic Great Barrier Reef is in trouble, but they are just starting to realize the extent of the damage that’s been brought on by climate change.

The reef is one of the largest living structures on earth, stretching 1,400 miles, but despite being so massive it can be seen from space, it’s still incredibly fragile. Scientists who have been studying the reef have been raising concerns about its future, but now a new study has shed even more light on the damage that’s been brought about by climate change.

IMG_PA040021_previewA researcher assesses minor damage at Day Reef on the Great Barrier Reef following the March 2016 mass coral bleaching event. Credit: Gergerly Torda/ARC Centre of Excellence for Coral Reef Studies.

Scientists studied satellite maps and examined individual species of coral, and found the reef has been forever altered. The changes they documented are the result of a massive coral bleaching event, brought on by higher ocean temperatures.

According to their work, which was just published in the journal Nature, an extreme heat wave in 2016 caused a catastrophic die-off that killed more than half of the corals in the northern third of the reef, but that wasn’t even the extent of the damage. They also found that 30 percent of the coral across the entire reef had been lost.

IMG_P30700146_previewThe different color morphs of Acropora millepora, each exhibiting a bleaching response during mass coral bleaching event. Credit: Gergely Torda/ARC Centre of Excellence for Coral Reef Studies.

Coral has a symbiotic relationship with tiny algae, known as zooxanthellae, that provide it with food and give it its color. When coral is stressed because of high ocean temperatures, or other causes like pollution and acidification, it expels the algae living in its tissues, which exposes its white skeleton, leaving corals to starve.

IMG_P3080383_previewA severely bleached branching coral among the minimally bleached boulder coral. Credit: Gergely Torda/ARC Centre of Excellence for Coral Reef Studies.

Corals may recover over time if stressors are reduced, but if they continue the coral will die. Unfortunately, a second marine heat wave hit in 2017, causing another damaging bleaching event that led to the death of another 20 percent of corals.

In all, about half of the corals in the reef have been wiped out in just two years. Some of the corals didn’t even live long enough to starve, they just died almost immediately from heat stress.

IMG_P2143110_previewThere are variations in the appearance of severely bleached corals. Here, the coral displays pink fluorescing tissue signaling heat stress. Credit: Gergerly Torda/ARC Centre of Excellence for Coral Reef Studies.

Even if some corals recover, it will take years and the ecosystem won’t resemble what it once was. If there’s any good news here, it’s that some species are a bit tougher than others, and have survived in the damaged areas affected by heat, but scientists believe the reef has been forever altered.

IMG_3265_Hoogenboom_previewThere are ‘winners’ and ‘losers’ among corals as they respond to the accumulating impacts of climate change. Credit: Mia Hoogenboom/ARC Centre of Excellence for Coral Reef Studies.

“The coral die-off has caused radical changes in the mix of coral species on hundreds of individual reefs, where mature and diverse reef communities are being transformed into more degraded systems, with just a few tough species remaining,” said the study’s co-author Professor Andrew Baird, of the Australian Research Council Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University in Queensland.

Losing a coral reef ecosystem like the Great Barrier Reef wouldn’t just be a tragedy in and of itself, it would be devastating blow to biodiversity. The reef provides a home for thousands of species, and it draws millions of people every year who want the opportunity to experience it in person.

Sadly, bleaching events are becoming more common, putting the Great Barrier Reef, and other reef ecosystems, at risk. While the Great Barrier Reef may be different in the future, scientists believe there’s still time to save what’s left with quick action on our part to limit carbon emissions.

Photo credit: ARC Center of Excellence for Coral Reef Studies

129 comments

shana l
shana lyesterday

Just notice how many hits the environment has taken since Mr. (not my President) Trump took office. The Paris Climate Summit was just the beginning of how many ways he is harming our environment and our planet. We may not survive the next two years.

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Karen N
Karen N24 days ago

Human arrogance, activity and lifestyle and destruction of the environment is the major cause of climate change and global warming with humans destroying animals, other creatures, their habitat, trees, woodlands, forests, polluting oceans, trashing and raping the earth we live on. Humankind may achieve many things but the biggest achievement of all (and NOT an achievement to be proud of) will be that of the destruction of all forms of life on earth and that of the earth itself and therefore the demise of the human species and all for the sake of governments, politicians and those alike who put arrogance, constant-development, business, and profits etc. before the welfare of others, animals, their habitat and the environment. After all the devastation and destruction by humans I very much doubt mother earth will ever be able to heal herself, let alone the Great Barrier Reef. Those with such a disregard for this earth and other life forms on it do not deserve to live on this planet, they should be sent to some sterile planet where there will just be them and their egos to share it with.

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Yvonne T
Yvonne T24 days ago

sad sad sad....

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Georgina M
Georgina M25 days ago

What a pity. We just do not care they seem to think " out with the old in with the new"NOT realizing that it's THE ONLY ONE.Coal Barons will learn too late just what they have accomplished by their GREED

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Freya H
Freya H25 days ago

We keep fouling our nest, and soon we will have no nest at all. Nature will not put up with our greed, or our breeding like rabbits, or our rape of the planet's resources. It is only a matter of time before a fearful pandemic sweeps across the globe. Antibiotic resistance plus a highly mobile population equals a recipe for unstoppable disease.

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Past Member
Past Member 25 days ago

Future generations will curse the rest of the world for not uniting in 1996 to demand a 100 percent greenhouse emissions reduction from Australia by 2010 or even 2006.

Australia is – no questions – the worst offender when it comes to greenhouse gas emissions. It has the highest per capita greenhouse emissions, yet the lowest average homeothermic basal metabolic rate (ecological energy consumption) of any nation on Earth.

De facto, Australia is ruled by a small number of wealthy coal and mineral industries, who cannot tolerate and do not permit any government interference in their absolute right to pollute. Nor do the majority of Australian question it, for the simple reason that this de facto plutocracy means much lower taxes with a vastly larger land and resource base than available to residents of Europe, East Asia or New Zealand. Australia’s public does occasionally bemoan inaction its dreadful greenhouse emissions record, but it fails to recognise that a complete seizure of the existing de facto political system is a prerequisite for the slightest change, because the vastly higher taxes and living costs that would result are not accepted.

If the rest of the world had been marching on Canberra to demand a completely new constitution mandating a carbon-free economy and 100 percent investment in rail, renewable energy, and relegation to 90 percent protected area, Australia would have avoided t

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Mark Donner
Mark Donner25 days ago

It's too late for Earth. You can say goodbye to the incredible diversity and beauty of life on planet Earth. You can't change humans, they will destroy anything good, and there's seven billion of them infecting this planet. It's not the end of life, there are countless other life planets thriving in the galaxy and the universe, that fortunately don't have to face the contamination and evil of the human cancer on life.

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Deborah W
Deborah W25 days ago

Half of the Great Barrier Reef has died since 2016, the damage brought about by climate change. And what about the damage that brought about climate change in the first place? HUMANS on their own path to self-destruction and eventual extinction. Well done good and faithful servants !!!

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Dana W
Dana W26 days ago

How awful.

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Virginia M
Virginia Miller26 days ago

So very sad

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