The Red Sea Could be a Climate Refuge for Coral Reefs

A large new marine protected area could help some of the world’s most heat-tolerant corals survive the century, if the pressures from resorts, industry and other development ease.

Aerial view of a heavily touristed reef near resort developments near Sharm El-sheikh, Egypt. Runoff from landscaping at the resorts is a potential threat to the health of the reefs. Credit: Bob Berwyn
Aerial view of a heavily touristed reef near resort developments near Sharm El-sheikh, Egypt. Runoff from landscaping at the resorts is a potential threat to the health of the reefs. Credit: Bob Berwyn

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When Lina Challita dives along Egypt’s coast, she doesn’t just see a colorful array of corals and fish. She sees hope. Against the grim backdrop of climate models that project most coral reefs dying by the end of this century in overheating oceans, the northern end of the Red Sea may end up being one of the last places on Earth where those critical ocean ecosystems can survive, at least at least for a while, and perhaps longer if countries of the world manage to cap global warming and stabilize the climate.

The reefs in the northern Red Sea could show scientists how some other reefs might adapt to global warming, and perhaps even serve as a nursery for corals to restore reefs in other areas.

A recent proposal for a vast new marine protected area encompassing the Red Sea’s reefs could be a step toward ensuring their survival, and the possibility of spreading the hope growing there to other coral ecosystems.

“What is needed are proper integrated coastal zone management plans that are enforced,” Challita said last November, looking out over the coastal reef zone near Sharm el-Sheikh, Egypt, where the most recent U.N. climate summit was held that month. “You have to take into consideration all stakeholders, from oil and gas to the shipping industry, to fishing, tourism and coastal development, and try to find the good middle between all of those, with the priority of protecting as many of these reefs as we can.”


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Challita, environmental manager at Egypt’s Chamber of Diving & Watersports has been diving in the area for 17 years and promotes Green Fins, a reef protection program focusing on reducing impacts to reefs from recreational diving and snorkeling. She said she’s seen the corals and fish stocks decline, but said that they are still in good shape compared to other reefs that have been devastated by recent ocean heat waves. A protection plan that mitigates existing impacts and prevents new ones would keep them that way for a few more decades.

“I know that it has the potential to recover, if we allow it to,” she said.

But, she warned, that has to happen within about five years, as she anticipates the climate reaching 1.5 degrees of warming in the 2030s, and reef resilience needs to be bolstered as much as possible before that increase in heat arrives. 

Time is of the essence because the northern Red Sea is warming about 0.45 degrees Celsius per decade—four times faster than the mean rate of global ocean warming—according to a 2017 study in the journal Scientific Reports. And, with the reefs in the region in very shallow water, and very close to shore, they are vulnerable to both rising ocean heat and the impacts of activities on land, including sediment runoff and pollution, said Mark Eakin, former director of the National Oceanic and Atmospheric Administration’s Coral Reef Watch program.

To date, ocean heat, which kills corals by bleaching—a disruption of the symbiotic relationships between the various microorganisms they are composed of—hasn’t really affected the corals in the northern Red Sea, said Suez University marine biologist Mahmoud Hanafy, who is also a member of the Hurghada Environmental Protection & Conservation Association.

“We have more than 50 scientific articles giving very clear evidence that Egyptian reefs could be one of the last refuges for corals worldwide until the end of this century,” he said. 

Based on those findings, global conservation groups focusing on ocean ecosystems have recently identified the Red Sea’s reefs as a global “hope spot.” Just ahead of COP27, the recent climate talks in Egypt, Mission Blue and The Ocean Agency ramped up a push to establish broader protection for the reefs, and the United States contributed $15 million to launch the Red Sea Initiative “to help protect the coral reef and surrounding coastal ecosystem against the impacts of climate change and human activity.”

The Red Sea Initiative is a foundational element of the bilateral agreement between the U.S. and Egypt on economic cooperation and aims to establish “a long-term, private-sector led approach to conserve and restore the Red Sea coral reefs,” according to the U.S. State Department.

“We found that, until the end of the century, the sea in this area won’t reach a temperature that will cause bleaching,” Hanafy said. “So, I’m saying protection of the reef is not our national task. It is a global task. This is a last refuge, a hope for coming generations.”

Red Sea Reefs Can Take the Heat, but Not All the Pressure

But time may be running out. Some research suggests “a decline in coral growth and calcification across the thermal range of Red Sea corals,” and there was widespread bleaching in the central Red Sea during 2015, a year when 70 percent of reefs globally were exposed to potentially damaging warm ocean temperatures. Surveys eight months after the bleaching showed a “general decrease in coral cover and species richness across all reefs surveyed,” in the central Red Sea, with the most significant changes in reefs near the coast.

Global warming, fishing, pollution and other impacts severely degraded about 14 percent of reefs globally, with repeated waves of bleaching between 2009 and 2018, according to the Global Coral Reef Monitoring Network.

Coral reefs are critical ocean ecosystems because they serve as nurseries for many species of fish that are important food sources for coastal communities. Although they cover less than 1 percent of the ocean floor, reefs nurture about 25 percent of all marine species and help provide livelihoods for at least half a billion people, according to the Intergovernmental Panel on Climate Change. They also buffer shorelines from rising sea levels and storm surges by breaking incoming waves.

A fossilized coral reef in Ras Muhammad National Park near Sharm El-Sheikh, Egypt. Because much of Egypt's Red Sea coast is made up of such fossilized reefs, with very little topsoil, the living reefs in the water are vulnerable to any pollutants that might be in surface runoff.
A fossilized coral reef in Ras Muhammad National Park near Sharm el-Sheikh, Egypt. Because much of Egypt’s Red Sea coast is made up of such fossilized reefs, with very little topsoil, the living reefs in the water are vulnerable to any pollutants that might be in surface runoff. Credit: Bob Berwyn

Corals in the northern Red Sea have an evolutionary advantage because the larvae that established the reefs arrived relatively recently in Earth’s history and had to pass through the extremely warm waters at the southern end of the sea. Their new home provided some advantages. Prevailing ocean currents carry cold water from the depths to the surface all year long, and there is very little runoff of reef-damaging sediments and pollution from the extremely dry adjacent land areas.

But a 2019 study identified numerous threats from human activity, including the presence of oil terminals, unsustainable tourism, lack of sewage treatment, increasing desalination activities, new oil pipelines and proposals for major infrastructure projects like a bridge from Egypt to Saudi Arabia and the Red Sea to Dead Sea canal. 

“There is no doubt we have some problems,” Hanafy said. The reefs are overused, he said, because economic development of the coastline started before conservation became important, and the “main indicators of success were the number of tourists and the number of hotels. We forgot about the carrying capacity of the ecosystem. So we ended with very intensive development in some areas of the Red Sea, like you have seen in Sharm el-Sheikh.”

Save What’s Left

The coastal development at the expanding tourist destinations along the Red Sea affects the reefs in a way that’s not quite as visible as dive boats dropping their anchors on corals, but it can be just as destructive, Challita said. She questions the concept of sustainable tourism development.

“I kind of do not think we’re going about it in the right way at all,” she said. “There’s very little that is sustainable about the way we live. So sustainable development is a concept that doesn’t make sense, if the essence of the problem is the way we live. Now the system is broken, so everything we’re doing is plugging holes.”

Protecting the northern Red Sea’s coral reefs probably requires rethinking the coastal tourism model, she said. Many of the expanding hotel complexes on the coast are putting a lot of greenery into the desert environment, bringing in exotic plants that require irrigation, fertilizers and pesticides. And most of the shore is made of fossilized reefs that grew when sea level was much higher than it is now.

“It’s very sandy,” she said. “It has no clay, so whatever water you put on this type of land, it leeches straight into the sea. It just runs off, so I believe that one of the silent forms of pollution that you have from the hotel industry is this runoff from all of the irrigation.”

Challita said she has long advocated banning grass, at least at the beachfront of hotels, to reduce chemical-laden runoff from the lawns into the sea.

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She also said the current focus on replanting corals with fragments grown in nurseries may be misguided. As the rapid global demise of coral reefs has become widely known, the idea of restoring them has garnered increasing publicity, leading to unrealistic hopes in technological solutions, she said. But, at least in areas like the northern Red Sea, she said, where “we still have a reef that is functioning,” protecting and preserving what’s there makes more sense than planning to restore it while allowing the activities driving its decline to continue.

“This would maybe be OK in an area that’s been completely destroyed by dynamite fishing, and you’re rebuilding—then we plant coral,” she said. “But the whole idea around coral planting, the technology is not there. A reef is a mix of various species that grow together over time. What makes a reef ecosystem is when a variety of species make peace with each other to create shelter for other life.”

That’s not easy to recreate, and while new coral restoration projects are often touted as environmental gains, many of them may be destined to fail. 

“In most of the coral growing projects I’ve followed, I’ve noticed that they have a one or two year success rate,” she said. “And then something happens in the third or fourth year, where the little seedlings are not doing as well, or they completely die. Nobody writes about that.”

Overall, she said, such projects have a very low success rate, despite their early promise.

“Scientists say our corals in the Red Sea will survive 1.5 degrees Celsius warming, while about 70 or more percent of the rest of the world’s corals are likely to disappear once we get to 1.5,” she said. “We’re at 1.2 now, so they are our hope for once we reach 1.5. But we do not know what will happen once we’re at 1.8.”

The fate of the Red Sea corals remains uncertain for now, she added, and will depend not only on how warm the water gets, but on whether management of the sea and the land surrounding it can be transformed.

“What we do know is that, if you give them a chance, they will be resilient, and they can recover,” she said.