Coral reefs in Australia bleached by a marine heat wave

Australia has many superlatives with regard to its natural landmarks. The large barrier reef, the largest coral reef system in the world on the northeast coast, is rightly recognized as a UNESCO World Heritage site. Burning of biodiversity, it is the dream of a diver.

But there is a less known record on the other side of the country, on the northwest coast of Australia: Ningalo Reef.

At a 2 p.m. road north of Perth, Ningaloo is unique. The largest reef in the world and another of the UNESCO World Heritage Sites in Australia, it houses a lush ocean forest that spreads along the coast for hundreds of kilometers.

From the desert beaches far from the region, you can travel vibrant turquoise waters and almost immediately start diving with a dive with a dive with a diving with a marine landscape also famous for its vibrant corals like the fauna around them – the MANTA rays, the Recipes and the Whale Sharks.

But this year, Ningaloo was in difficulty. Struck by a marine heat wave, higher water temperatures highlighted the corals and they have become white, in an effect called “whitening”. Although some can recover, it is not a fact – and the damage surprised scientists.

Not only that, but the heat wave is responsible for another more disturbing superlative. This is the first time that the reefs on the western and eastern coasts of Australia have been blanched.

“It is like an underwater bush fire that has been raging that has persisted for months now, hurting the coast,” explains Paul Gamblin, who heads the Australian Marine Conservation Society. “It is an absolutely devastating event and people are in shock. It is enormous. It is unprecedented. It is absolutely not normal.”

The marine heat wave that damages Ningalo began in the Caribbean in 2023. It then crossed the Indo-Pacific coral reefs and damaging on its way. In 2024, while the Grande Barrier Reef saw money laundering, Ningaloo was spared. But at the end of last year and at the beginning of 2025 – a peak top – the temperatures had started to skyrocket in Australia -Western.

All of this is part of the fourth global laundering event, which, according to experts, affected more than 80% of the world’s coral reefs.

Dr. Kate Quigley, principal researcher of the Minderoo foundation, compares the effect to a stomach bug.

“Instead of having bacteria in the human intestine, corals have this small symbol of algae which lives inside their cells which allow them to make biological processes,” she explains, adding that these algae are what gives corals their color. When the water becomes too hot, this relationship is breaking down and whitening begins.

“So, a bit like, if we have a stomach bug and the human body does not work in the same way, [it’s the] Same thing with coral, “she explains.” Lukewarm water causes biological processes inside this coral. And just as humans fall sick, corals fall sick too. “”

Dr Quigley is particularly worrying, the scientists of prolonged warming have seen. They expected the temperatures to drop by April over the summer peak. This year, this did not happen.

“In previous warming events, water temperatures may have increased for a little time, then go down so that corals can mainly recover – they can bounce back,” said Dr Quigley. “But what we are really afraid to see, especially in the coming months, are really high levels of death.”

While government scientists have watched the reef, there are still a lot of things they do not know.

“The natural world is an incredibly variable place, and sometimes we are … shocked by what we see, [because] This does not seem to follow the rules, “said Dr. Tom Holmes, the program manager of marine sciences in the department of biodiversity, conservation and attractions in Western Australia.

Dr. Holmes and his team carry out follow -up investigations between three and six months after money laundering to assess how many corals are dead.

“There are certainly coral recordings [being] In a bleached state during this period and still surviving, “he says.” So we just need to play the waiting game now. “”

Ningaloo attracts around 200,000 tourists in its waters each year. For swimmers and divers, however, the damage is clear.

“It was like diving with Tuba in a corpse,” said Jenna-Rae Clark, the British-South African tourist, who has been at the top of the Ningaloo coast in recent weeks. “It was so gray and lifeless. You can sometimes hear fish snacking on the coral – there was nothing.”

For residents, there is an additional fear: that tourists turn their backs in Ningalo.

“People were really devastated in the back of the summer, and many people talk about how they were crying in the water, leaving the really upset ocean,” said Sara Morgillo, who moved here from Perth to dive and work in conservation.

“There are still incredible parts of the reef here which are worth seeing and we always organize diving visits every day,” she adds.

“I think it is also very important to see what is going on and [see] The effects of the marine heat wave we had. “”

Scientists all agree on what causes this heat wave: the increase in carbon emissions warms the planet and its oceans. According to NASA, the ocean is the place where 90% of global warming occurs – and the last decade was the hottest since the 1800s. Last year was the hottest ever recorded.

These more worrying superlatives threaten the famous monuments of Australia. But there is also another more cultivated problem.

Just at the top of the Ningaloo coast is one of the largest fossil fuels in the world, the North West gas plant. In May, the Australian government announced that it would allow Woodside, the company that runs the project, to operate it until 2070.

The same company also tries to obtain approval to develop the largest reserves of unexploited gas in Australia in the navigation basin, higher on the coast.

Although these projects do not alone create the heat that damages Ninguo, it is a symbol of competing interests in Western Australia – where the gas industry feeds the economy much more than tourism.

“The large barrier is the body and Ningalo is sources of deep wonder, the equivalent of Antarctica or Serengati or Amazon,” explains Paul Gamblin of Australian Marine Conservation Society.

“The juxtaposition is incomprehensible: at a time when places like Ningalo clearly suffer from the consequences of climate change, so that the government even plans to open new fossil fuels projects … This should not occur, and governments must trace a line in the sand and make a clear commitment not to worsen the situation.”

While the wider debate continues on the use of fossil fuels, scientists work to better understand the reef in order to help it.

Dr. Chris Roelfsema of the University of Queensland and his team map Ningalo – plunging under the ocean to take close photos of corals and binding them with satellite images. In this way, they can better follow their health.

“People ask me, what can we do? Well, the first thing you can do is choose politicians who plan to reduce fossil fuels and are [supportive of] Renewable energies, “explains Dr. Roelfsema.” Your vote has a voice for politicians, so you can choose it. But you can also drive less, [use] Public transport, not having your air conditioning all the time – these are all things that can help reduce our footprint. “”

There is also laboratory science. Dr. Quigley and his Minderoo team have selectively selected coral combinations to find out which types are the most tolerant at higher temperatures.

“We have these fertilized eggs of many different genetic horizons and we raise them over a series of days until we have coral babies, coral adolescents,” she explains. “Like butterflies, corals also undergo different metamorphoses and stages.”

By testing these corals, researchers can assess which are more tolerant at higher temperatures. Then the idea is to put them back in the water.

While Dr. Quigley did this in the big coral barrier, it is at a stage much earlier here in Ningalo – and it admits that the method is not ideal.

“It would be very difficult to evolve for all the reefs in the world,” she concedes. “It would be much more logical to obtain the deep cause, which are emissions, for this long -term livelihood of coral reefs.”

Considered by critics as a simple sticky plaster, there is pressure for the authorities to do more. This brings Dr Quigley back to the analogy of the bush fire.

“Interesting, when bush fires occur here in Australia, the authorities are very quickly there – there is a lot of response,” she said. “You don’t see that on coral reefs in Australia.”

One of the reasons may be because they are risky corals, not people. After all, there are no houses on the way to the underwater bush fire.

Experts say, however, that such a point of view is short -sighted. The coral reefs house 25% of all marine life. But they also deal with human life.

“They are absolutely supercharged with nature and diversity and support the smallest creatures to the largest,” explains Paul Gamblin. “They also support millions of livelihoods from people all over the world and protect the coast of storm waves and extreme storm events that we see more with climate change. They therefore provide huge services to the planet.”

These services are often forgotten by those above the surface. But while fossil fuels continue to warm the planet, life in the oceans feel the heat.