As the early morning sun rises over the Great Barrier Reef, light permeates the turquoise waters of a shallow lagoon, bringing more than a dozen turtles to life.
These waters around Lady Elliot Island, off the east coast of Australia, offer some of the most spectacular snorkeling in the world – but they are also on the front lines of the climate crisis, as one of the first places to see coral masses suffer. bleaching event that has now spread throughout the world.
The Great Barrier Reef just experienced its worst summer on record, and the US-based National Oceanic and Atmospheric Administration (NOAA) announced last month that the world is experiencing a rare global mass coral bleaching event – the fourth since the late 1990s – impacting at least 53 countries.
The corals are victims of rising global temperatures that have broken historic records over the past year – caused mainly by fossil fuels driving up CO2 emissions and accelerated by the El Niño weather pattern, which is warming ocean temperatures in this part of the world.
CNN witnessed bleaching on the Great Barrier Reef in mid-February, on five different reefs spread across the northern and southern parts of the 2,300-kilometre-long ecosystem.
“What’s happening in our oceans now is akin to underwater forest fires,” said Kate Quigley, principal investigator at Australia’s Minderoo Foundation. “We’re going to have so much warming that we’re going to reach a tipping point, and we’re not going to be able to come back from that.”
Bleaching occurs when marine heat waves stress corals, causing them to expel algae from their tissues and lose their color. Corals may recover from bleaching as temperatures return to normal, but they will decay if water remains warmer than normal.
“It’s an extinction,” says Professor Ove Hoegh-Guldberg, a climate scientist at the University of Queensland in Australia and chief scientist at The Great Barrier Reef Foundation. “Temperatures got so warm that they’re off the charts… they’ve never been at this kind of level before.”
The destruction of marine ecosystems would deliver an effective death sentence for about a quarter of all species that depend on reefs for their survival – and threaten an estimated one billion people who depend on reef fish for their food and livelihoods. Reefs also provide essential protection for coastlines, reducing the impact of floods, cyclones and sea level rise.
“Humanity is being threatened at a rate that I’m not sure we really understand,” Hoegh-Guldberg said.
‘I pray the corals come back’
After taking off from Brisbane just after sunrise, our small propeller plane skims miles over the Queensland coastline before flying north over the crystal clear waters of the Coral Sea – revealing the beauty of this vast reef system beneath the surface.
Our destination is Lady Elliot Island, a remote coral cove atop the southern end of the Great Barrier Reef.
Pilot Peter Gash is the tenant of the island and his family has been organizing trips to the island for almost twenty years.
“We made it our life’s work,” Gash said. “My wife and I got married, I started flying and learned to fly planes so I could bring people here.”
Gash maneuvers his small plane through bumpy crosswinds to land safely on the short, grass-covered runway.
Decades ago, the island was a barren landscape devoid of vegetation after years of mining for nutrient-rich seabird waste – known as guano – in the late 19th century.
The Gash family set out to bring this island back to life by planting approximately 10,000 native tree species to create an artificial forest and nature reserve, and using solar energy, batteries and a water desalination system to create a small ecotourism resort to support.
The island is now home to around 200,000 seabirds, which have contributed to the regeneration of the coral reef on the island’s edge.
“If we can fix this little place, this little circle, we can fix this big place – this whole planet,” Gash said. “That’s what really drives me: trying to encourage people to know that it’s not hopeless, but that it can be done.”
Gash takes CNN on a snorkeling tour and dives down to explore the underwater rainforest in his backyard. The vibrant coral colonies are bursting with color and teeming with hundreds of species, including manta rays, reef sharks, clownfish and turtles.
When the island’s biggest enthusiast surfaces to catch his breath, even he can’t hide his shock at the extent of the coral bleaching.
“It’s worse than I thought it would be,” Gash said, kicking water over the surface. “I just pray the corals come back next year.”
‘Quiet as a graveyard’
Beyond the Great Barrier Reef, the massive marine heatwave sweeping across the globe has already affected some of the world’s most famous coral reefs, including those in the Red Sea, Indonesia and the Seychelles.
Last year, rising ocean temperatures also caused widespread destruction of corals in the Caribbean and Florida – and US experts predict further damage there next summer.
“I’m increasingly concerned about summer 2024 for the broader Caribbean and Florida,” said Derek Manzello, the coordinator of NOAA’s Coral Reef Watch program.
“It won’t take much additional seasonal warming to push temperatures past the bleaching threshold.”
In February, NOAA added three new levels to its coral bleaching warning maps so scientists can assess the new scale of underwater warming.
Scientists hope the grim images of mass bleaching events – and the bleak predictions for the longer-term survival of coral reefs – will spur world leaders to take aggressive action to reduce carbon emissions by moving away from fossil fuels.
Researchers are also trying to buy some time for coral reefs until the world can get emissions under control.
Over the past six years, Peter Harrison and his team at Southern Cross University in New South Wales have been developing a ‘coral IVF’ program to increase coral reproduction on the reef. The researchers use fishing nets to capture the brood of healthy breeding coral, then grow the larvae in floating pools before releasing them onto damaged parts of the reef to aid recovery.
“We need to act now to keep corals alive on as many reefs as possible around the planet,” Harrison said.
Research projects are also underway at the Australian Institute of Marine Science (AIMS) looking at growing heat-resistant corals that can survive higher temperatures, and developing AI tools to try to make some processes scalable to the enormous size of the reef.
The Australian government has been criticized for pouring hundreds of millions of dollars into countless reef research projects, while doubling the use and production of the fossil fuels driving climate change – and even opening four new coal mines in 2023 has approved.
“We have the terrible dissonance that Australia is mining, selling to be burned on a massive scale, and at great speed, the very same pollution that is driving the destruction of this beautiful place,” said David Ritter, CEO of Greenpeace Australia. CNN on the top deck of a boat near Briggs Reef, in the northern Great Barrier Reef.
Australia has committed to getting 82% of its electricity from renewables by 2030 and has set out legislation to achieve net zero emissions by 2050. But that pace of transition is too slow for many activists, who point out that the planet still faces years of warming. come from carbon pollution already entering the atmosphere.
“The truth is that even more disasters, fueled by climate change, are baked into the system,” Ritter said.
Scientists predict that, at the current rate of warming, the average global temperature by 2050 could be 2 degrees Celsius above pre-industrial levels. At that level of heat, 99% of coral reefs will simply die.
For the marine biologists witnessing this extinction, there is a real sense of mourning.
Everyone connected to the reef “struggles” with feelings of sadness and helplessness, says David Wachenfeld, research program director at AIMS.
“Coral reefs are, at best, a canary in the coal mine when it comes to climate change,” he said. “The trajectory we are following now is really very frightening.”
Harrison, the researcher at Southern Cross University, described it as ‘ecological grief’.
“When you swim across a reef system that was vibrant and colorful just a few months earlier, the sounds of the reef were incredible,” he said.
‘And when you swim over it again, it all looks like a graveyard. It’s as quiet as a cemetery.”
The documentary ‘Warning to the World: Australia’s Climate Disasters’ airs this Sunday, May 5 at 8pm ET on The Whole Story with Anderson Cooper.
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