Searching for Heat-Resilient Corals to Protect People and Nature in the Face of Climate Change

Around the world, rising ocean temperatures are devastating corals. More than 84% of the world’s reefs have been hit by temperatures hot enough to cause “bleaching,” during which corals expel their colorful, life-sustaining algae and turn white.

The warming waters and increased bleaching caused by climate change are pushing corals toward the “tipping point” of extinction, potentially erasing them forever.

But as scientists study these threatened reefs, they have noticed something surprising—the damage is not uniform. Some corals keep their colors and survive.

These heat-resilient corals offer a powerful tool—and hope—in the fight against climate change.

“We know there are corals out there that are surviving heat waves and increasingly warmer temperatures,” said Annick Cros, The Nature Conservancy’s resilience science lead for Global Oceans. “We need to find those resilient corals and protect them before they are lost to other threats, so that reefs have a chance to survive climate change.”

Finding “the best of the best” corals to fight climate change

Climate change not only threatens coral reefs, but also the communities that rely on them for survival. Coral reefs are the most biologically diverse and economically valuable ecosystems on Earth. They cover less than 1% of the planet’s surface, yet they support 25% of all marine life. More than 1 billion people rely on coral reefs for food, income and daily survival.

The discovery of heat-resilient corals offers hope for the future—but hope without action is not enough. These unique corals face other potentially lethal threats from pollution, overfishing and unsustainable development. Conservation strategies that reduce these pressures allow heat-resilient corals to continue supporting people and nature in the face of climate change. Ensuring their survival also means they can serve as “mother reefs,” spreading larvae—baby corals—to other areas where they can grow into new resilient reefs.

To protect these special corals, scientists first must find them. To that end, The Nature Conservancy partnered with Stanford University and the Woods Hole Oceanographic Institution (WHOI) to launch the Super Reefs project. For the past three years, the partners have piloted innovative strategies in Belize, Hawaiʻi and the Marshall Islands to identify and protect heat-resilient corals.

Combining cutting-edge science with traditional Indigenous knowledge, the Super Reefs team developed the “Predict, Prove and Protect” framework through which WHOI created scientific models to predict areas where heat-resilient corals are most likely to thrive. TNC and Stanford University then collected coral samples from those areas and put them through thermal testing to prove their resilience. Once their heat-resilience was confirmed, TNC began working with local communities, government agencies, conservation groups and others to help design effective protection plans to keep the reefs safe for the future.

“It has really instilled in me hope and possibility,” said Nicole Craig, reef resilience specialist for TNC in Belize. “It can get a little depressing at times seeing the decline of the reefs. But we’re finding the best of the best corals. We’re training people how to use these tools and how to support efforts that keep hope alive. It’s a fight worth fighting.”

“Everyone has seen the decline of the reefs. Everyone knows something has to be done,” said Tiara Stark, project manager with TNC’s Maui Marine Program. “It’s exciting that we can share these climate-smart strategies to reinforce the resilience of the corals.”

Stark added that Hawaiʻi’s super reefs can serve as a bridge to protect coastal systems as conservation strategies take hold.

“We’re working to stop the local stressors on the coral reefs. But the reality is, that takes a long time,” Stark said. “These resilient corals help us get ahead of the curve. They’re giving us an upper hand.”

“As reefs around the world face growing threats, protecting those that show signs of resilience is more important than ever,” said Dolores deBrum-Kattil, executive director of MICS. “Reef refugia offer an opportunity to safeguard marine biodiversity and build more resilient communities in island nations like ours, which are especially vulnerable to climate change.”

Yimnang Golbuu, coral resilience director for TNC in Micronesia and Polynesia, said the Super Reefs project is helping empower small island nations as they confront growing climate threats.

“It’s not just the big countries that can play a role in fighting climate change,” Golbuu said. “Building the capacity and conservation expertise of local communities offers a smarter, more resilient approach to reef restoration.”

Sharing local lessons for a global impact

The Super Reefs team is part of a global movement working to identify and protect reefs that can withstand the rising ocean temperatures caused by climate change. Working with communities, conservation partners and policy leaders around the world, the team is sharing its data, knowledge and on-the-ground experience to ensure coral reefs will be around for generations to come.

“By placing practical tools in the hands of communities, we enable them to discover resilient corals on their own and lead the way in protecting them,” remarks Courtney Kleypac from Stanford University, who has been training communities at Super Reefs sites.

Marine conservationists from Belize will soon join a Super Reefs learning exchange in the Dominican Republic, where they will learn climate-smart restoration strategies and best practices for selecting and propagating heat-resilient corals. The training will serve as a pilot to launch similar learning exchanges worldwide.

TNC also is working with partners to develop a Climate-Smart Reef Restoration Guide to help scientists, communities, conservationists, governments and others learn how to identify, protect and propagate heat-resilient corals on damaged reefs, and how to monitor success. The guide will be shared at global workshops and conferences, and through the Reef Resilience Network, a partnership of more than 10,000 coastal conservation practitioners and experts aimed at strengthening the capacity of marine managers across the globe.

“We are taking what we learned in Belize, Hawai‘i and the Marshall Islands, and we’re bringing that knowledge to a global audience,” said Joe Pollock, senior reef strategy lead for TNC’s Hawai‘i and Palmyra Programs. “The ability to identify and protect resilient reefs is an incredibly powerful tool in the fight against climate change—and a source of hope for reefs and the people who depend on them.”

That hope is already being seen—not just in the number of heat-resilient corals that are now being protected, but also in the growing number of people moving the work forward.