Wonder No More?

Question: More than 90% of what watery wonder may disappear within ten years?

Answer: Great Barrier Reef

While it’s highly doubtful we’ll see Victoria Falls reduced to a trickle or the Northern Lights flipping on a dimmer switch any time soon, Australia’s Great Barrier Reef is another story.

A recent scientific study suggests that under current conditions, 90% or more of the living coral will be completely gone from the massive central and southern sections of the Great Barrier Reef—in just ten years.

Surely that must be an exaggeration, right? Haven’t we been hearing warnings about reef decline and coral bleaching for decades now? Yet they always seem to recover, don’t they? Maybe this is just another of those Aesop’s tales of The Boy Who Cried "Reef!" …

Unfortunately, it isn’t.

The main culprit (but not the only one)—global warming
The Great Barrier Reef has already lost half of its living coral primarily due to global warming since 1995. The large, branching coral types that served as habitats for a wide range of sea life were the most harmed.

Coral polyps, which form the backbone of the reef, are sensitive little fellas. When ocean temperatures rise, it causes them to expel the algae that live in their tissue. Deprived of their main food source, the corals turn completely white—a process known as coral bleaching. Given enough time to recover, corals can usually survive this bleaching. But the increasing frequency off mass bleaching events in recent years is making it next to impossible for corals to recover.

In the summer of 2024, the Great Barrier Reef experienced its most extreme mass bleaching event ever recorded—and the reef’s fifth mass bleaching event in just eight years. What’s even more alarming is that scientists have just discovered that ocean temperatures around the Great Barrier Reef are now the hottest in at least 400 years—almost half a degree Fahrenheit above the previous record high. (How they could possibly know this would be a fair question—it involves drilling into the cores of coral to identify geochemical changes and reconstructing past sea-surface temperatures.) But it’s not just human-driven climate change that is destroying the Great Barrier Reef. There’s another culprit under the sea, one that looks nothing like Nemo …

Crown-of-thorns starfish—killers of the coral reef
Some of the blame for the destruction of the Great Barrier Reef goes to a spiky marine creature called the crown-of-thorns starfish. These are no ordinary starfish, however. Anywhere from nine inches to up to three feet in diameter, these deadly beauties have up to 21 arms, no brains, and bodies entirely covered in two-inch venomous spines. But it’s not the venom that makes them dangerous—it’s their feeding habits.

Crown-of-thorns starfish dine on polyps of hard, relatively fast-growing corals. They do this by extruding their stomachs onto the coral reef and then using enzymes to digest the coral polyps—a process that takes several hours. After digestion is complete, these starfish on steroids just move on to another section of the reef, leaving behind a white coral skeleton.

In normal numbers on healthy coral reefs, crown-of-thorns starfish are not a problem. In fact, they represent an important part of the ecosystem and enhance the coral diversity of the reefs. But when outbreaks occur, watch out. Because they feed much faster than the coral can grow, large numbers can devastate huge sections of the reef. When we talk about how 50% of the living coral in the Great Barrier Reef has been destroyed since 1995, crown-of-thorns starfish were responsible for half of it.

The Australian government has poured millions into programs to prevent crown-of-thorns starfish outbreaks—and culling existing starfish populations—in recent years. One pilot program tasked 25 divers to inject bile salts directly into 1,000 starfish a day over a nine-day period—which killed almost a quarter of a million of them. The jury is still out on whether the program was a success, however. Some even say it has made the problem worse. Another strategy was installing giant, million-dollar fans that were trained on a small section of the reef to cool the water down and prevent coral bleaching.

All these efforts are just buying time, of course. Already, the Great Barrier Reef is unable to recover from bleaching events that are becoming more and more common. In the long term, reducing global warming is the only thing that’s going to save it.

And if the Great Barrier Reef doesn’t make It—what then?
Losing the Great Barrier Reef means we lose all coral reefs—Australia’s Great Barrier Reef is just the largest one. Consisting of thousands of individual reefs, islands, and cays, it stretches for some 1,400 miles along the coast of Queensland, covering an area of 133,000 square miles—the equivalent of about 70 million football fields, or roughly the size of Japan. And never mind what you heard about the Great Wall of China, the Great Barrier Reef is the only living structure that can be seen from outer space.

Coral reefs aren’t known as the "rainforests of the sea" for nothing. Covering less than 1% of our oceans, they provide essential habitat for 25% of all marine life—well over a million species around the world. If their homes and spawning grounds are gone, untold numbers of fish, turtles, and other sea creatures would disappear.

Coral reefs aren’t just lovely diving sites, either. They protect coastlines by providing a natural barrier against powerful waves and extreme weather events. Without coral reefs, shorelines would be far more vulnerable to erosion and rising sea levels. Currently, about 200 million people around the world rely on coral reefs to protect them from storms. The costs of building sea walls to replace them would be staggering.

Like the actual rainforests, plants and animals that live within coral reefs provide a wealth of cutting-edge medicines to treat everything from cancer and arthritis to heart disease and Alzheimer’s.

Coral reefs also provide food and livelihoods for hundreds of millions of people around the world. Does it even need to be said? The entire world must do their part in cutting carbon emissions and reducing global warming because the Great Barrier Reef—and our planet—are worth saving.

5 fun facts about the Great Barrier Reef

• An Australian safari anyone?—The Great Barrier Reef has an aquatic counterpart to Africa’s "Big Five" called the "Great Eight." They include the clownfish, giant clams, manta rays, Maori wrasse, potato cods, sharks, turtles, and whales.


• No vacancies under the sea—As a marine habitat, the Great Barrier Reef can be likened to the Australian rock band Crowded House. This bustling underwater metropolis is home to more than 1,500 species of fish, 215 species of birds, more than 3,000 species of mollusks, six of the world’s seven species of marine turtles, 30 species of whales and dolphins, and dugongs, relatives of the manatee often called "sea cows" because they peacefully graze among the sea grasses of the reef.


• The devil in the deep blue sea—Using sensitive lowlight cameras to trawl the deepest sections of the ocean floor around the reef, researchers have found bizarre prehistoric sea life lurking in the depths. Along with ancient six-gilled sharks and giant oil fish, the most exciting find was the primitive shell-dwelling Nautilus, which appears to have remained relatively unchanged over the last 500 million years. To attract the creatures, the research team went old school—they used a tuna head on a stick.


• Underwater museum will take your breath away—The Museum of Underwater Art (MOUA), located in the shallows of the Great Barrier Reef some 50 feet below the waves, features several underwater sculpture installations anchored to the seabed—all except one. The only part of the museum visible above the surface is a life-like sculpture hooked to a temperature gauge in the reef. It changes color as a real-time response to water conditions, serving as a reminder to the dangers facing the ecosystem.


• Reefer madness—While exploring the waters of the northern end of the Great Barrier Reef, Australian scientists recently discovered a detached reef more than 1,600 feet high—taller than the Empire State Building. It’s the first large, detached reef found in the area since late in the 19th century. During the same expedition, they also discovered dozens of yet-to-be-classified species of corals, sponges, and scorpionfish, as well as a 150-foot-long siphonophore (a jellyfish-like marine animal)—believed to be the longest sea creature ever recorded.

Visit the Great Barrier Reef during our A South Pacific Odyssey: Australia, the Outback & New Zealand adventure.