Australia’s Great Barrier Reef isn’t dead yet. But it’s dying.
What’s killing the largest coral reef system on the planet? The short answer is us. We’re killing it via warmer waters, ocean acidification, pollution, poaching, and overfishing.
Right now, scientists are most concerned about something called coral bleaching. This debilitating process has been serious enough to merit major concern four times in the reef’s recorded history: in 1998, 2002, 2016, and 2017. Bleaching typically occurs when warm water stresses the coral polyps—the trillions of tiny animals that make up a reef—causing them to expel zooxanthellae, the photosynthetic algae that live within the polyps and serve as their principal food source, as well as the source of their Technicolor appearance. Though bleached coral isn’t dead, it’s weakened significantly by the loss of these algae; as a result, it’s far more likely to become diseased and to die. And while coral can recover, it generally takes about 10 years of normal (i.e., cooler) water temperatures for it to do so.
Given the warming trends over the past two decades, the Great Barrier Reef doesn’t appear to stand much of a chance.
Coral reefs like the Great Barrier Reef are among the most biodiverse habitats—some say the most biodiverse—on the planet. Though they occupy less than 1 percent of the ocean floor’s real estate, they’re host to more than a quarter of all marine life. And the range of ecosystem services that they provide is staggering. The world’s fisheries depend on them to the tune of $6.8 billion each year. They serve as natural seawalls, protecting coastlines from destructive waves. And the symbiotic process that takes place between the coral polyps and the algae living within their porous structures is essential to maintaining levels of carbon, nitrogen, and other nutrients in the ocean ecosystem.
No one disputes the value and importance of coral reefs. Australians, for their part, positively revere the Great Barrier Reef and are currently in something like a state of collective shock upon realizing that its condition has deteriorated so quickly—and that they might not be able to experience it for much longer, at least not in the way they have in the past.
But the sad, simple truth is that coral bleaching isn’t the only factor that has led us to this critical juncture. Australians love the Great Barrier Reef so much that they’ve developed much of the Queensland coast adjacent to it, all so that people can live, work, fish, and vacation alongside this 1,400-mile-long natural wonder. Over the past 150 years, the resulting runoff from the land has profoundly altered the coastal geography, such that every year, millions of tons of sediment and nutrients pour onto the reef, wreaking ecological havoc. Fish and coral populations are smothered by the sediment. Meanwhile, the nutrient overload feeds algae—the wrong kind of algae—and crown-of-thorns starfish. As the starfish disproportionately thrive, they devour reef coral at an unsustainable rate.
And while poaching and illegal fishing don’t pose the same threat they once did, thanks to better regulation and stronger enforcement, these activities still take place. Taken together, all these injuries constitute a searing indictment of our—by which I mean humanity’s—passive-aggressive relationship with the natural spaces that have given us so much for so long in terms of resources, ecosystem services, beauty, and identity.
They give and so we take—except we don’t know when to stop taking. These natural wonders are stunningly beautiful to look at, and so we develop the land beside them—except we don’t know when to stop developing. They show us when they’re suffering, and so we vow to heal them by mending our ways—except we can’t bring ourselves to do that just yet.
Last week, scientists announced that they had discovered what they believe is a new breed of “super corals” in the South Pacific. These corals seem to have successfully adapted to the warmer, more acidic, and less oxygenated seas that now characterize the Great Barrier Reef ecosystem (and so many others). Should such super corals be found off Queensland, as the scientists hope they will be, then all hope may not be lost. Maybe, the researchers say, these specimens can flourish under what we have taken to be highly suboptimal conditions and repopulate the reef for the remainder of the Anthropocene.
This news should make us very happy—but it should also make us very uneasy. If it turns out that the Great Barrier Reef is “saved” by the emergence of corals that have somehow managed to adapt to our mistreatment of them, what’s to stop us from continuing down the unsustainable path we’ve already set for the reef, and for ourselves?
Or to put it another way: What’s to stop us—in our apparently limitless hubris—from assuming that nature will always find a way to temper our destructiveness and to compensate for the sins we’ve committed against it?
onEarth provides reporting and analysis about environmental science, policy, and culture. All opinions expressed are those of the authors and do not necessarily reflect the policies or positions of NRDC. Learn more or follow us on Facebook and Twitter.
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