On a boat off the coast of an island near Abu Dhabi, marine scientist Hamad al-Jailani feels the corals, picked from the reef nursery and packed in a box of seawater, and studies them carefully, making sure they haven't lost their color. The corals were once bleached. Now they're big, healthy and ready to be moved back to their original reefs in the hope they'll thrive once more. "We try to grow them from very small fragments up to — now some of them have reached — the size of my fist," al-Jailani said, who's part of the Environment Agency Abu Dhabi's coral restoration program. Also Read: Red Sea corals threatened by mass sea urchin die-off, Israeli researchers say The nursery gives corals the ideal conditions to recover: clear waters with strong currents and the right amount of sunlight. Al-Jailani periodically checks the corals' growth, removes any potentially harmful seaweed and seagrass, and even lets the fish feed off the corals to clean them, until they're healthy enough to be relocated. The Environment Agency Abu Dhabi, or EAD, has been rehabilitating and restoring corals since 2021, when reefs off the United Arab Emirates' coast faced their second bleaching event in just five years. EAD's project is one of many initiatives — both public and private — across the country to protect the reefs and the marine life that depend on them in a nation that has come under fire for its large-scale developments and polluting industries that cause harm to underwater ecosystems. There's been some progress, but experts remain concerned for the future of the reefs in a warming world. Also Read: Coral reefs' survival at stake: Unesco Coral bleaching occurs when sea temperatures rise and sun glares flush out algae that give the corals their color, turning them white. Corals can survive bleaching events, but can't effectively support marine life, threatening the populations that depend on them. The UAE lost up to 70% of their corals, especially around Abu Dhabi, in 2017 when water temperatures reached 37 degrees Celsius (99 degrees Fahrenheit), according to EAD. But al-Jailani said 40-50% of corals survived the second bleaching event in 2021. Although the bleaching events "did wipe out a good portion of our corals," he said, "it did also prove that the corals that we have are actually resilient ... these corals can actually withstand these kind of conditions." Bleaching events are happening more frequently around the world as waters warm due to human-made climate change, caused by the burning of oil, coal and gas that emits heat-trapping gases into the atmosphere. Other coral reef systems around the world have suffered mass bleaching events, most notably Australia's Great Barrier Reef. How to limit global warming and its effects will be discussed at length at the United Nations climate conference, which will be held in Dubai later this year. Also Read: Rare, pristine coral reef found off Tahiti coast The UAE is one of the world's largest oil producers and has some of the highest per capita greenhouse gas emissions globally. The country has pledged to have net zero carbon emissions by 2050, which means all carbon dioxide emissions are either slashed or canceled out somehow, but the goal has been met with skepticism from analysts. But bleaching due to warming weather is not the only threat to coral reefs around the gulf. High oil tanker traffic, fossil-fuel related activities, offshore installations, and the exploitation of marine resources are all putting marine life under intense stress, according to the U.N. Environment Programme, causing them to degrade. Environmentalists have also long criticized the UAE, and Dubai in particular, for its large-scale buildings and huge coastal developments. The building of the Palm Jebel Ali, which began more than a decade ago and has been on hold since 2008, caused an outcry among conservationists after it reportedly destroyed about 8 square kilometers (5 square miles) of reef. "More than 90 million cubic meters (23.8 billion gallons) of sediments were dredged and dropped, more or less on top of one of the remaining reefs near Dubai," said John Henrik Stahl, the dean of the College of Marine Sciences at Khorfakkan University in Sharjah, UAE. The project was meant to be similar to the Palm Jumeirah — a collection of small, artificial islands off the coast of Dubai in the shape of a palm tree. Still, environmental projects persist across the coastline and throughout the emirates. Development company URB has announced it wants to grow 1 billion artificial corals over a 200-square-kilometer area (124 square miles) and 100 million mangrove trees on an 80-kilometer (50-mile) strip of beaches in Dubai by 2040. Still in the research and development phase, the project hopes to create 3D technology to print materials that can host algae, much like corals. Members of Dubai's diving community are also encouraging coral protection efforts. Diving course director Amr Anwar is in the process of creating a certified coral restoration course that teaches divers how to collect and re-plant corals that have fallen after being knocked off by divers' fins or a boat's anchor. "I don't want people to see broken corals and just leave them like that," said Anwar. "Through the training we give people, they would be able to take these broken corals that they find and plant them elsewhere, and then see them grow and watch their progress." But experts say that unless the threat of overheating seas caused by climate change is addressed, coral bleaching events will continue to occur, damaging reefs worldwide. Countries have pledged to limit the global average temperature rise to 1.5 degrees Celsius (2.7 degrees Fahrenheit) since pre-industrial times, after which scientists say the effects of warming on the planet could be much worse, and some even potentially irreversible. But analysts say most nations — including the UAE — are still way off that target. "You have to make sure that the cause for the degradation of the coral reefs in the first place is no longer a threat," said Stahl, the Khorfakkan University scientist. "Otherwise the restoration effort may be for nothing."  

Deep in the South Pacific, scientists have explored a rare stretch of pristine corals shaped like roses off the coast of Tahiti. The reef is thought to be one of the largest found at such depths and seems untouched by climate change or human activities. Laetitia Hédouin said she first saw the corals during a recreational dive with a local diving club months earlier. “When I went there for the first time, I thought, ‘Wow — we need to study that reef. There’s something special about that reef,” said Hédouin, a researcher at the French National Center for Scientific Research in Moorea, French Polynesia. Read:The heat stays on: Earth hits 6th warmest year on record What struck Hédouin was that the corals looked healthy and weren't affected by a bleaching event in 2019. Corals are tiny animals that grow and form reefs in oceans around the world. Globally, coral reefs have been depleted from overfishing and pollution. Climate change is also harming delicate corals — including those in areas neighboring the newly discovered reef — with severe bleaching caused by warmer waters. Between 2009 and 2018, 14% of the world's corals were killed, according to a 2020 report by the Global Coral Reef Monitoring Project. The newfound reef, stretching 2 miles (3 kilometers), was studied late last year during a dive expedition supported by UNESCO. Unlike most of the world’s mapped corals, which are found in relatively shallow waters, this one was deeper — between 115 feet (35 meters) to 230 feet (70 meters). Exploring such depths posed a challenge: the deeper a diver goes underwater, the shorter amount of time can be safely spent at each depth. The team was equipped with special tanks and did 200 hours of diving to study the reef, including taking photographs, measurements and samples of the coral. The reef is in a spot where many researchers haven't spent a lot of time in, said former National Oceanic and Atmospheric Administration oceanographer Mark Eakin. “We’ll be seeing more of these discoveries as the technology is applied to these locations,” said Eakin. “We may find some bigger ones somewhere, but I think this is always going to be an unusual reef.” Read:Scientists explore Thwaites, Antarctica's 'doomsday' glacier The recent volcanic eruption in Tonga that triggered tsunami waves across the Pacific has not affected the reef off Tahiti, said Hédouin. Hédouin hopes the research can help experts understand how the reef has been resilient to climate change and human pressures, and what role these deeper corals might play in the ocean ecosystem. More dives are planned in the coming months. “We know very little about the ocean, and there’s still so much that needs to be recorded, needs to be measured,” said Julian Barbière, the head of UNESCO’s marine policy and regional coordination.