Located off the coast of Queensland, Australia, the Great Barrier Reef is the largest coral reef system on Earth. It extends across an area of approximately 133,000 square miles and comprises more than 2,900 separate reefs. A World Heritage Site since 1981, it can be seen from space and is an Australian icon on par with Ayers Rock, or Uluru. It is home to more than 9,000 marine species (many of them endangered), and generates approximately $6 billion through tourism and fisheries every year.
Despite its status as a national treasure, the Great Barrier Reef has been plagued in recent years by a number of human and environmental factors. These include overfishing, pollution, and climate change. In 2012, a paper published by the Proceedings of the National Academy of Sciences estimated that the reef system had already lost half of its initial coral cover. Major coral bleaching disasters in 2016 and 2017 added to the environmental crisis and in August 2019, the Great Barrier Reef Marine Park Authority released a report stating that the long-term outlook for the reef system is "very poor".
In this article, we take a look at whether the largest single structure built by living organisms has a future; and if it's still worth visiting.
Developments in Recent Years
In April 2017, multiple news sources reported that the Great Barrier Reef was on its deathbed following a major bleaching event in the middle third of the reef system. The damage was documented by an aerial survey carried out by the Australian Research Council’s Centre of Excellence for Coral Reef Studies, which reported that of 800 reefs analyzed, 20% showed coral bleaching damage. These somber findings came on the heels of an earlier bleaching event in 2016, during which the northern third of the reef system suffered a 95% loss of coral cover.
Together, these back-to-back bleaching events wreaked catastrophic damage on the upper two thirds of the reef system. Results from a scientific paper published in the journal Nature in April 2018 showed that on average, one in three Barrier Reef corals died over a nine-month period following the 2016 and 2017 bleaching events. Total coral cover decreased from 22% in 2016 to 14% in 2018. In the Great Barrier Reef Marine Park Authority's most recent outlook report, no fewer than 45 separate threats were identified.
These range from rising sea temperatures to pesticide run-off and illegal fishing.
Understanding Coral Bleaching
In order to understand the severity of the 2016 and 2017 bleaching events, it is important to understand what coral bleaching entails. Coral reefs are made up of billions of coral polyps: living creatures that depend on a symbiotic relationship with algae-like organisms called zooxanthellae. The zooxanthellae are protected by the coral polyps’ hard outer shell, and in turn they provide the reef with nutrients and oxygen generated through photosynthesis. The zooxanthellae also give the coral its bright color.
When the corals become stressed, they expel the zooxanthellae, giving them a bleached white appearance.
The most common cause of coral stress is increased water temperature. Bleached coral is not dead coral. If the conditions that caused the stress are reversed, the zooxanthellae can return and the polyps can recover. However, if the conditions continue, the polyps are left vulnerable to disease and are unable to grow or reproduce effectively. Long-term survival is impossible, and if the polyps are allowed to die, the chances of the reef’s recovery are similarly bleak.
Global Causes of Coral Bleaching
The primary cause of coral bleaching on the Great Barrier Reef is global warming. Greenhouse gases emitted by the burning of fossil fuels (both in Australia and internationally) have been accumulating since the dawn of the Industrial Revolution. These gases cause heat generated by the sun to become trapped within the Earth’s atmosphere, raising temperatures both on land and in oceans all over the world. As the temperatures rise, so coral polyps like those that make up the Great Barrier Reef become increasingly stressed, ultimately causing them to expel their zooxanthellae.
Climate change is also responsible for a change in weather patterns. The effects of the 2016 and 2017 bleaching events were compounded by Cyclone Debbie, which caused significant damage to the Great Barrier Reef and the Queensland coast in 2017. In the wake of the disaster, scientists predicted that the Coral Sea will see fewer cyclones in the years to come; but those that do occur will be of a much greater magnitude. The damage caused to the area’s already vulnerable reefs can therefore be expected to worsen proportionately.
Local Factors Also at Fault
In Australia, agricultural and industrial activity on the Queensland coast are also contributing significantly to the reef’s decline. Sediment washed into the ocean from farms on the mainland suffocates the coral polyps and prevents the sunlight needed for photosynthesis from reaching the zooxanthellae. Nutrients contained in the sediment create chemical imbalances in the water, sometimes triggering harmful algal blooms. Similarly, industrial expansion along the coastline has seen major disruption of the seabed as a result of large-scale dredging projects.
Overfishing is another major threat to the future health of the Great Barrier Reef. In 2016, the Ellen McArthur Foundation reported that unless current fishing trends change dramatically, there will be more plastic than fish in the world’s oceans by 2050. As a result, the fragile balance that coral reefs depend upon for their survival is being destroyed. On the Great Barrier Reef, the damaging effects of overfishing are proven by repeated outbreaks of crown-of-thorns starfish. This species has spiraled out of control as a result of the decimation of its natural predators, including the giant triton snail and the sweetlip emperor fish.
It eats coral polyps, and can destroy large tracts of reef if its numbers are left unchecked.
The Future: Can it Be Saved?
As the August 2019 report proves, the outlook for the Great Barrier Reef is bad and getting worse. However, while the reef system is certainly sick, it isn’t yet terminal. In 2015, the Australian government released the Reef 2050 Long-Term Sustainability Plan, designed to improve the reef system’s health in an attempt to save its status as a UNESCO World Heritage Site. The plan has seen some progress, including a ban on dredging material being dumped in the World Heritage Area and a reduction of pesticides in agricultural run-off by 28%.
In the 2019 report, Great Barrier Reef Marine Park Authority CEO Josh Thomas announced that the Australian and Queensland governments will be investing AU$2 billion over the next decade in an attempt to protect the reef and increase its long-term resilience. Conservation efforts are already underway and have adopted a multi-faceted approach to the problem, focusing on goals such as improving water quality, addressing crown-of-thorns starfish outbreaks and finding ways to help reefs that have already been bleached to recover.
Ultimately, the most serious threats to the Great Barrier Reef are the result of global warming and overfishing. This means that in order for this reef system and others all over the world to have a future, government and public attitudes to the environment need to change both internationally and urgently.
The Bottom Line
So, with all that in mind, is it still worth traveling to the Great Barrier Reef? Well, it depends. If the reef system is your sole reason for visiting Australia, then no, probably not. There are many more rewarding scuba diving and snorkeling destinations elsewhere. Look to remote areas like eastern Indonesia, the Philippines and Micronesia instead.
However, if you’re traveling to Australia for other reasons, there are definitely some areas of the Great Barrier Reef that are still worth checking out. The southernmost third of the reef system is still relatively intact, with areas south of Townsville escaping the worst of the recent bleaching events. In fact, studies from the Australian Institute of Marine Science show that the southern sector corals are remarkably resilient. Despite the increased stress factors of the last decade, coral cover has actually improved in this area.
Another good reason to visit is that the income generated by the Great Barrier Reef’s tourism industry serves as a major justification for ongoing conservation efforts. If we abandon the reef system at its darkest hour, how can we hope for a resurrection?