One Man’s Quest to Heal the Oceans—And Maybe Save the World

Enric Sala—marine ecologist, conservationist, and ocean advocate—is standing under a life-size replica of a Northern Atlantic Right Whale at the natural history museum in Washington, D.C., and the air outside is smudged with wildfire smoke drifting down from Canada. It’s not surprising that Sala wants to talk about the smoke, or about whales. Their poop, however, is an unexpected twist. According to Sala, whale excrement, or, more precisely, the lack of it, has a role to play in the choking miasma that has forced my interview with one of the world’s foremost ocean explorers indoors instead of out on a boat.

It may seem like a stretch, the kind that relegates environmentalists deep into woo-woo territory, but as our conversation unfolds, it starts making sense. Whale poop fertilizes ocean plankton. The plankton reproduces rapidly, absorbing carbon dioxide as it photosynthesizes sunlight. Eventually it sinks to the seafloor, trapping the planet-warming gas in layers of sediment. Fewer whales means less plankton sequestering CO, leaving more in the atmosphere. That means more of the heat driving the wildfires that have smoked out much of North America.

“Suddenly, we’re seeing that the impacts of climate change are not something that is going to be suffered by somebody else,” says Sala. “It’s here.” And so it is, in the wildfires, heat waves, and floods that have made the weather of summer 2023 some of the most extreme on record. Greater bio­diversity, whether it is found in the ocean’s whale populations or the old-growth forests that also store carbon, can help mitigate the effect of burning fossil fuels much more cheaply than any new technology, he says. “The more nature we have, the more nature will be able to absorb our impacts.”


Photograph by Cristina Mittermeier—SeaLegacy

Sala’s links between healthy ocean ecosystems and human benefits like carbon sequestration are backed up by science that he has either committed to memory or conducted himself. But it’s the ability to break scientific complexity into simple concepts that even landlubbers can comprehend that makes him so effective as an ocean advocate, ­helping rally global governments to commit to protecting 30% of their coastlines and ocean territories by 2030. His Pristine Seas project, sponsored by the National Geographic Society, has identified dozens of the ocean’s most biodiverse hot spots in an effort to call for their protection. Already he has managed to get 2.5 million sq. mi. (6.5 million sq km) of coastline and ocean set aside in 26 marine protected areas (MPAs)—an expanse twice the size of India—where fishing, dumping, mining, and other destructive industries are prohibited.

On May 24, Pristine Seas’ scientific-research ship the E/V Argo lifted anchor for its most ambitious undertaking yet: a five-year expedition to the remote tropical Pacific, where Sala plans not only to chart the world’s biggest ocean from its unplumbed depths to its more familiar shores, but also to document the complex links between marine ecosystems and the lives they support on land in order to build a case for their conservation.

The ocean needs that help more than ever. The morning of our meeting, the European climate-­monitoring agency reported that May 2023 had seen the highest ocean temperatures on record, increasing ocean acidity, weakening marine eco­systems, and forcing coral polyps to expel their colorful symbiotic zooxanthellae algae in a near-death phenomenon called bleaching. By the end of July, waters off the coast of Florida had reached Jacuzzi temperatures, and volunteers were racing to transfer fragile coral sprouts to indoor aquariums before they cooked to death. According to the National Oceanic and Atmospheric Administration (NOAA), about 40% of the world’s oceans are currently experiencing a marine heat wave, with as much as 50% forecast for September.

The ocean has already absorbed more than 90% of the planet’s greenhouse-gas-fueled warming, explains Sala, “but it will not be able to ­absorb our ­impacts for much longer without serious consequences.”

Read more: A New Ocean Preserve Could Save the Waters Off Baja—And This Stunning Marine Life

The havoc wreaked on coral reefs destroys habitats that nurse, nourish, or shelter a quarter of all marine life, including the fish that provide critical protein and income to a billion people around the world. Goods and services provided by reefs in the form of tourism, shoreline protection, food, and fisheries are valued at $2.7 trillion a year. The economic consequences of reef loss are grim and looming ever closer, says Sala. A 2°C or higher rise in average global temperatures since humans started burning fossil fuels for energy would be enough to wipe out an estimated 99% of existing coral reefs. The month of July already averaged 1.5°C. “I find that I am rarely invited back to dinner parties,” he deadpans.

Still, says Sala, there is hope. His research has proved again and again that given the space to recover undisturbed from human exploitation, nature can bounce back. “A marine protected area cannot make that water cooler, cannot protect from warming, but what we know is that fully protected areas are more resilient.” He has watched pristine reef systems, bleached white by marine heat waves, recover within five years—but only when they have their full cohort of predators like sharks, along with the smaller inhabitants they prey upon. A reef, he says, isn’t just made up of coral. It is a delicately balanced ecosystem that includes bacteria, algae, plants, clams, crabs, urchins, herbivores, and the carnivores that keep them all in check. Take one element out, and the entire system becomes unstable. “You board a plane, and the pilot informs you that five screws are missing, but you don’t know from where. Would you still fly?” he asks.

Sala’s solution for protecting the ocean from rising heat is simple: identify the richest areas of bio­diversity and protect them from human intervention. Left alone, the resulting abundance will eventually spill over into unprotected zones, stocking new areas with fish that can be harvested for human consumption, while allowing for the evolution of genetic adaptation to a changing climate. MPAs, says Sala, are like an interest-bearing savings account. As long as you don’t touch the principal, you can live off the interest. “The only way to get more from the ocean is to have more life in the ocean,” says Sala. “And the only way to have more marine life is to set some places aside so it can thrive. It’s as simple as this.”


Sources: NOAA, Climate change Institute at the University of Maine, National Data Buoy Center, Mediterranean Heat Waves Monitoring Service, the Kelp Rescue Initiative, and studies published in the Regional Studies in Marine Science, Environmental Pollution, Nature. Credit: Rich Morgan

As an avid snorkeler growing up close to the near barren waters of Spain’s Costa Brava, Sala always assumed that the lush, underwater gardens of his favorite Jacques Cousteau documentaries could be found only in faraway tropical paradises. A chance scuba lesson in the Medes Islands marine park, one of Spain’s first MPAs, taught him that the Mediterranean could be just as much an underwater wonderland when it was protected from the region’s industrial fishing fleets. “Everything that was missing from the sea of my childhood was there,” he recalls. “The grouper, the sea bass, the scorpion fish, octopus, sea bream.”

That epiphany sparked an interest in marine conservation, and, with a Ph.D. in ecology, he went on to help establish the Center for Marine Biodiversity and Conservation in 2000 at the Scripps Institution of Oceanography, in La Jolla, Calif. But despite his tenured position, generous research grants, and the opportunity to work with the best ocean scientists in the world, he felt something was missing. “The places that I was studying were falling under the force of the relentless human sledgehammer,” he wrote in his 2020 memoir, The Nature of Nature: Why We Need the Wild. “Corals and seagrasses were dying everywhere, and fish were being taken out of the water faster than they could reproduce. Lush underwater gardens full of large animals were being turned into dead reefs overgrown by brown algae and murky jellyfish dystopias … I realized that all I was doing was writing the obituary of ocean life.” He felt, he says, like a doctor telling his patient how they would die, without offering a cure. So he quit, and went in search of one.

Since 2008, the program has conducted 38 expeditions, produced 30 documentaries, and published more than 250 peer-reviewed studies that have upended long-held assumptions about marine ecosystems, including the power of highly protected areas to rapidly restore depleted fish, coral reefs, and kelp forests in adjacent waters. In a 2021 paper for Nature, Sala demonstrated that protecting 30% of the ocean would also deliver benefits for commercial fisheries and carbon sequestration. He identified key areas that, if protected, would provide the most benefit in terms of nature conservation, food production, and climate mitigation, a kind of more-bang-for-your-protection-buck checklist that he is now trying to persuade local governments to implement. Overall, Pristine Seas has midwifed a total of 26 MPAs into existence, helping raise the percentage of protected ocean from 1% to 8%.

That’s still significantly less than the 30% that scientists say is necessary to protect ocean bio­diversity. Sala visibly flinches when reminded of that shortfall, and acknowledges the pressures piling up since he started 15 years ago, from a quadrupling of plastic waste to higher temperatures and increased fishing pressures. “Now I’m working on the cure, but the patient is getting worse and worse,” he concedes. “We fix the lungs. But oh, now there’s something wrong with the liver. Oh, and there is a blood clot. So yeah, it’s a Sisyphean task. But that’s what makes me keep going. I don’t see a bigger purpose than working to save life on earth.”

Pristine Seas was inspired by a National Geographic story about an explorer who trekked across central Africa and persuaded the President of Gabon to create a chain of national parks to protect the region’s wildlife. Sala wondered if the same could be done for the oceans. In 2007, Sala approached the National Geographic Society with a proposal to combine exploration, research, policy, and documentary film to build a case for local governments to establish national marine protected areas. He envisioned Pristine Seas as a kind of scientific SWAT team, refining our understanding of ocean life, by sending divers, submersibles, and cameras into waters previously unplumbed by research, and working with economists, ecologists, and climate scientists to calculate the value of preserving what they found.


Off the coast of Chile’s San Felix Island, National Geographic Explorer in Residence Enric Sala documents observations of deep sea fauna from the DeepSee submarine at a depth of 250 meters.

Avi Klapfer—National Geographic

In a 2009 expedition to Kiribati’s Southern Line Islands, a chain of uninhabited atolls 1,800 miles southwest of Hawaii, Sala found reefs that had never seen pressure from commercial fisheries, a “thriving coral jungle full of large fish.” Before then, he says, scientists “had no idea what pristine reefs looked like.” In 2015 and 2016, disaster struck. A marine heat wave triggered coral bleaching in more than half the reef. Sala thought he was witnessing the destruction of one of the ocean’s last intact coral colonies. But a return visit in 2022 demonstrated a “miraculous” recovery. Coral was growing back, and the fish were as plentiful as they had ever been. “It recovered like a phoenix,” says Sala.

Documenting the reef’s recovery wasn’t enough. Sala wanted to understand why those coral survived the heat, when so many other reefs did not, and how that recovery could be replicated elsewhere. Sala theorized that grazing fish had kept the bleached coral free of the brown algae that usually takes over, enabling the coral polyps to start growing again. In June, Pristine Seas returned to the area in one of the first stops of its new Pacific expedition, in part to test Sala’s hypothesis. Was it the presence of large numbers of fish? Or because larvae from other, less affected corals were able to take root among the ruins? Had the surviving corals evolved some sort of heat resistance? “If we believe that high protection is a key ingredient for coral resilience, we need the data,” he says.

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