Lisa Carne was swimming through a bed of seagrass in northern Belize when she saw a hunk of elkhorn coral lying loose on the sandy bottom. She paused to look at it. With its rich amber color and antler-like branches, the fragment seemed alive despite having broken off from its mother colony. A professional diver, Carne was struck with an idea: What if she picked this up and moved it to a patch of dead reef? What if she did it over and over again? Could she help the reef recover more quickly?
Carne kept thinking about the fragment as she finished up her dive. The reefs close to her home, near Laughing Bird Caye National Park, in southern Belize, had recently been decimated by a hurricane. When she returned home, she sat down at her computer and started searching online for anything she could find on reef restoration.
A few years later, she began to fashion an underwater nursery near Laughing Bird Caye. Borrowing techniques from academic research, she used rebar and steel mesh to make a pair of underwater tables. She would swim around the reefs she had identified as resilient with a pair of pruning shears, cutting small chunks from healthy colonies. She brought each one to the shallows long enough to glue it to a concrete disk, then “planted” the fragments underwater on her metal tables. Slowly, they grew. Then she started transplanting her corals directly onto the reef.
Today, Carne’s nonprofit, Fragments of Hope, works with local fishers to identify promising spots and track the fate of every piece of coral they place on the reef. And it ranks among the most successful and longest-running coral restoration programs in the world. When I spoke to Carne on Zoom last fall, she had set her virtual background to show the fate of her first plantings on the dull gray rubble of dead reef. Branching corals the color of mustard filled the frame. “You can’t count that!” she said proudly, gesturing at the dense thicket behind her.
This article appears in the May 2022 issue. Subscribe to WIREDIllustration: Mike McQuade
Yet for all of its success, Fragments of Hope’s program is still incredibly small. It has taken Carne and her team more than a decade to plant 160,000 coral fragments on less than 9 acres of reef. Worldwide, reefs cover an area millions of times that size. As Greg Asner, a researcher at Arizona State University who directs a global coral mapping program, put it, “No coral restoration projects of any kind or anywhere have been done at a scale that would really save a reef. Coral restoration has not summed up to even 1/100,000th of the area of shallow coral reefs worldwide.”
Coral reefs anchor some of the most vibrant ecosystems on the planet, home to a quarter of the oceans’ biodiversity in a tiny fraction of their total area. Half a billion people worldwide depend directly on reefs to protect their coastlines, support local fish populations, and attract tourists. But in the past 70 years, pollution, overfishing, and climate change have killed off half of the world’s reefs. By the end of this century, we may be speaking about healthy coral reefs in the past tense.
For years, Carne and others in the coral restoration field struggled to attract major funding for their efforts. That appears to be changing. In 2020, the insurance company Swiss Re crafted a policy to pay out nearly $1 million to send teams of divers to stabilize and replant corals that had been ripped out by a hurricane along the shoreline near Cancún, Mexico. Last year, the United States’ Defense Advanced Research Projects Agency issued a request for multimillion-dollar proposals for reef-building projects to protect US military installations.
Scientists, too, are coming around to the idea of large-scale experiments that might improve reefs’ resilience. For a long time, the sheer scale of reef systems made many people reluctant to contemplate regrowing corals. “It seemed like it was poking around the edges of the problem,” says Joanie Kleypas, who studies reefs and climate change at the National Center for Atmospheric Research.
Emboldened, scientists have been crossbreeding wild specimens taken from hundreds of miles apart to try to create hardier, heat-resistant variants. They have been freezing key samples of genetic material so that the scientists of the future can try to bring back some of the genetic diversity lost due to climate change. Ruth Gates, the late coral biologist and director of the Hawai‘i Institute of Marine Biology, told the The New Yorker in 2016 that she couldn’t bear the idea that future generations may not experience coral reefs: “We’re at this point where we need to throw caution to the wind and just try.’’ To rebuild reefs at scale takes a different kind of effort—and, perhaps, a different kind of person.
