Australia’s Great Barrier Reef has experienced some of the most rapid coral bleaching in its history. Until the late 20th Century, mass coral bleachings occurred as rarely as once every thirty years, but now experts say that if trends remain the same, by the 2030’s the reef will experience numerous devastating mass bleachings as often as every two years. In 2016 and 2017 the reef experienced some of the worst mass bleachings in history, where the entire reef network was under high alert. Since then, the reef has suffered greatly, and scientists say that although some parts of the network will recover, it would never look the same again. The Great Barrier Reef developed over 25 million years ago, and is home to over 600 different dazzling species of coral, and the largest open ocean coral reef network providing a habitat to 1,625 fish species, 215 bird species, 133 sharks and rays, 30 whales and dolphins, and 6 of the 7 different turtle species in the world. Aside from the environmental value of the reef, it has an icon asset value of $56 billion, and contributes almost $7 billion to the Australian economy annually. It supports over 60,000 jobs, and brings 2 million visitors per year.
The threats to the reef have been almost completely human caused. Human influence has resulted in a 50% decline in coral cover from 1985 to 2012, and that number is only increasing. Threats to the reef are three-pronged. First and foremost, changes in climate due to increased carbon in the atmosphere affects the reef the most. Rising sea temperature causes a greater risk of heat stress and mass coral bleaching. Ocean acidification caused by carbon being absorbed into the ocean changes the chemical makeup of the coral’s living space. Rising sea levels also cause land inundation which significantly changes tidal habitats on the edges of the reef systems, which permeates throughout the whole network. And increased frequency of severe weather events can destroy and weaken the reef structure, and more extreme rainfall events will magnify the issues surrounding sediment and chemical runoff which causes algae blooms over the reef. Secondly, increased sedimentation can cause higher algal growth, reducing the vital sunlight that gets down to smothered corals, and causing pollutants in sediments to build up among marine species. The third and final threat to the reefs surrounds coastal developments in agriculture, mining, industrialization, and residential growth. Each subsection causes pollutants to soak into the soil which then runs off into the coastal ocean systems, killing the coral around it.
A future without the world’s largest coral reef is unimaginable and horrifying, but hope is not lost. Some of the brightest minds in the world are focusing on decoding and uncovering the secrets to saving the single largest coral network in the world. The Paris Climate Accords show a glimmer of hope for the world’s dying environments, and each day experts unveil new and innovative proposals and solutions for curbing the dyoff of our planet’s largest undersea ecosystem. Through future research, building reef resilience, monitoring and improving water quality, and increased protection of endangered species, we might just be able to save what’s left of the beautiful Great Barrier Reef.