The Great Barrier Reef consists of about 3,000 individual coral reefs that together cover about 134,000 square miles along the coast of the province of Queensland, Australia. (YouTube/Queensland, Australia)

Australia’s iconic Great Barrier Reef may become irreparably damaged in the coming decades due to traumas caused by both nature and humans, leading scientists say.

The dire warning comes in response to plans by the Australian government to start a massive expansion of the deep-water coal port in Abbot Point, on the northeast coast, a move that scientists have said could be a tipping point for the delicate and world-renowned marine environment already under fire from many factors, including invasive species, climate change and human pollution.

“The reef is one of the natural wonders of the world, but science is telling us that it is rapidly deteriorating on our watch,” said Dermot O’Gorman, head of the World Wildlife Fund/Australia, a conservation group.

Great Barrier Reef threatened once more

The Great Barrier Reef consists of about 3,000 individual coral reefs, 750 islands and 300 coral cays that together cover about 134,000 square miles along the coast of the province of Queensland.

This natural wonder is large enough to be seen from outer space, and it’s teeming with so much life that in 1981 it was named a UNESCO World Heritage site. The reef is home to more than 1,500 species of tropical fish, along with sharks, dolphins and 400 species of coral. It’s also a breeding ground for humpback whales.

It is, according to UNESCO, “one of the richest and most complex natural ecosystems on Earth, and one of the most significant for biodiversity conservation. The amazing diversity supports tens of thousands of marine and terrestrial species, many of which are of global conservation significance.”

For someone exploring the reef for the first time, doing so is a breathtaking experience. Jordan Casey, a marine biologist from South Carolina who is working on a PhD thesis related to the reef, recalls being mesmerized during her first dive. “I had never seen an underwater ecosystem so crowded with vibrant life forms,” she recalls, “the high level of coral cover and the incredible diversity of fishes, which was a stark contrast to my experiences diving in the temperate zone of the United States and in the Caribbean. Above all, the colors were spectacular,” she said.

Hard corals vie for space and energy-giving sunlight off Cairns, Queensland, Australia. (David Doubilet/Getty Images/National Geographic Creative)

Yet the reef she saw was substantially degraded in many places from what it was like in the 1980s. According to a report from the Australian Institute of Marine Science, about half of the reef’s coral died between 1985 and 2012.

The report blamed damage from an increased frequency of tropical cyclones and the persisting presence of crown-of-thorns starfish, or COTS, an invasive, coral-eating species, as the main culprits behind the decline, followed by coral bleaching caused by rising sea temperatures. When those factors weren’t present, the reef was able to recover somewhat.

No breaks recently

“Our data show that the reefs can regain their coral cover after such disturbances, but recovery takes 10-20 years,” Hugh Sweatman, one of the study’s authors, said in a statement when the report was released. However, the reef, most of which is a protected marine park, has not had a break in the recent decades, noted Sweatman, with “intervals between the disturbances generally too short for full recovery, and that’s causing the long-term losses.”

Scientists say that other factors are also threatening the reef, which in some spots is quite close to the shoreline. Jon Day, former director of heritage conservation at the Great Barrier Reef Marine Park Authority, points to diminishing water quality, caused by agricultural runoff, coastal development and questionable fishing practices, as important problems.

Glenn De’ath, lead researcher on the study, said the runoff is significant because it provides nutrients for the invasive starfish to flourish. “Outbreaks of COTS have been linked to terrestrial runoff that enhances the survival of the larval stage of COTS development through nutrient enrichment,” he said in an e-mail.

Cardinalfish zip by a hawksbill turtle as it rests among hydroids in Queensland, Australia. (David Doubilet/Getty Images/National Geographic Creative)

“The Australian government’s own reports describe the declining condition of the Great Barrier Reef, and correctly identify climate change as the greatest future threat,” said Terry Hughes, a professor at James Cook University and director of the ARC Centre of Excellence for Coral Reef Studies in Queensland. “Yet they still want to develop massive amounts of fossil fuel and ship it across the reef. The last thing the reef needs is more CO2 in the atmosphere and more coastal dredging for huge coal ports,” he adds.

Along with these generalized concerns comes a specific new threat, scientists say: an expansion of the Abbot Point port to improve shipping from the major coal-producing region on Australia’s northeastern coast.

The port issue

The expansion is predicted to generate about 28,000 jobs and would probably bring in many more ships, but they would need to navigate near or through the reef. The government has said that the port expansion has been planned with environmental concerns in mind and that care is being taken to ensure that the reef will not be harmed. Greg Hunt, the minister for the environment, said in February that the federal and Queensland governments will spend around 2 billion Australian dollars (US$1.5 billion) for its protection over the next decade.

Michael Roche, chief executive of the Queensland Resources Council, which represents developers of the province’s minerals and energy sector, says port development and commercial shipping “have successfully coexisted with the World Heritage values of the Great Barrier Reef over several decades.”

Black band disease on Acropora muricata: Coral reefs in much of the Pacific Ocean are dying faster than previously thought. (Jordan Casey)

White coral syndrome: The coral reef decline is driven by climate change, disease and coastal development. (Australian Institute of Marine Science/AP)

But some scientists disagree. Roche’s claim “cannot be taken seriously in the face of 50 percent loss of coral cover over the last 30 years,” said David J. Miller of the ARC Centre.

The central issue with the expansion project concerns the fate of the huge amount of spoil — rocks, soil and other materials — that would be created. Initially the plan had been to dump the dredged material into the ocean, but an outcry stopped that. The government is now considering dumping it in wetlands, near coastal waters. But scientists and environmentalists say dumped spoil might eventually wash into the sea, affecting the reef.

“The dredging process itself is going to cause damage, irrespective of where the spoil is dumped,” Miller says. “Fine particles will travel long distances and cause damage and stress to reefs. . . . [Corals] can cope with some stress, but not with multiple kinds of stress simultaneously.”

One alternative being pushed to protect the reef would be to build a jetty out into water deep enough to accommodate coal-transport ships, says Jon Brodie, chief research scientists for the Center for Tropical Water and Aquatic Ecosystems Research at James Cook University. But this idea has gained no traction with the government so far — in part, he says, because of the expense.

Whatever happens, the fate of the reef is important for Australia, which derives billions of tourism dollars from visitors to it, and for the world. When President Obama visited Australia last fall, he mentioned that the “incredible natural glory” of the reef was being threatened, adding that he hoped the reef will still be there “50 years from now.”

The Malaysian container ship Bunga Terati Satu is seen after it ran aground on Australia's Great Barrier Reef in Nov. 2000. The ship was carrying a cargo described as dangerous goods along with 1,320 tons of fuel oil. (Brian Cassey/AP)

Obama made it clear he was blaming global warming for the threat, but his comments sparked a sharp response from the government anyway. “We have committed significant resources to preserve and conserve the reef,” foreign affairs minister Julie Bishop said. “We have demonstrated world’s-best practice . . . to ensure the Great Barrier Reef is preserved for generations to come.”

In the meantime, UNESCO has been considering whether to put the reef on its list of “World Heritage Sites in Danger” due to coastal development, including the port expansion and its impact on water quality and coral loss, with a decision expected this year.

No one wants to see the reef on UNESCO’s “in danger” list. It would be disastrous for the reef’s tourism industry, Hughes says, adding, “Australia can afford to do better.”

Gruber is a freelancer based in Perth, Australia.