South-east Asian idylls – from Philippine islands to the Thai bay made famous in The Beach – plan to turn tourists away so that devastated coral reefs have some time to recover. Will it be enough?

Our Thai tour guide, Spicey, takes a drag on her cigarette and gestures sadly towards the beach. “The problem with people is that they are too greedy. They see a beautiful place and they want it. They take, take, take from nature. And then they destroy it.”

The golden sands of Maya Bay where Spicey stands are some of the most famous in the world. This once-idyllic cove, on the tiny Thai island of Koh Phi Phi Leh, was the paradise location of The Beach, Danny Boyle’s 2000 film starring Leonardo DiCaprio. It was then pushed by tourism officials in advertising campaigns to entice more wealthy visitors to Thailand.

But mass tourism has since taken a vast toll on the fragile coral reefs here: 80% of the coral around the bay has been destroyed, the result of millions of boats dropping anchor on it, tourists treading on and picking it, or poisoning by rubbish and suncream.

Quick guide Coral in crisis: last chance to act Show Hide What is coral? Coral is made up of layers of skeletons of tiny animals called polyps. Over many years, these colonies form banks that are known as reefs. Only the living surface of the coral is coloured – the layers of dead matter beneath are white. Where are reefs found? Coral reefs are located in tropical oceans. The world’s largest coral reef is the Great Barrier Reef in Australia. The second-largest is off the coast of Belize, in central America. Other reefs are found in Hawaii, the Red Sea, the Persian Gulf and the Indian Ocean. Because they need sunlight to survive, the reefs form in waters that are usually no deeper than 45 metres. Why are they important? They protect coastlines from damaging wave action and tropical storms; provide habitats for thousands of species of marine organisms; and generate essential nutrients for food chains. They are also a critically important source of revenue. It is estimated that the Great Barrier Reef alone supports a tourism market worth more than A$1.5bn (£842m) a year to the Australian economy. Why are the reefs dying? The temperature of our oceans is rising as global warming grips our planet. When the water temperature gets too warm, corals expel the algae that thrive in their tissue and provide them with nutrition. Coral without the algae quickly die of starvation. Tourism is also taking its toll. When boats carrying visitors drop anchor, they smash into reefs and spill oil into once-pristine waters. Hotels also pump sewage on to the reefs, as our report points out. How bad is the threat? Marine biologists estimate that roughly 75% of the world’s coral reefs face danger. Local threats include destructive fishing, uncontrolled coastal development, tourism and pollution. Global threats include climate change and ocean acidification. How many reefs will die out? We have already lost about half of all the world’s coral reefs, most them having disappeared over the past 30 years. Scientists warn that even if we could halt global warming today, more than 90% of the reefs will die by 2050.

Robin McKie, Science Editor Photograph: Auscape/Universal Images Group Editorial

It is a sad tale replicated across the once-unspoilt bays and beaches of south-east Asia. It was here that the world’s greatest diversity of coral and marine life used to occur, but the reefs are now the most threatened on the planet, with 80% of what remains at high risk. Human pollution has combined with overfishing and the lucrative tourist trade to deliver appalling environmental destruction.

“What we are seeing now with coastal tourism in Boracay [in the Philippines], Maya Bay and Koh Phi Phi Leh is not new, but what is surprising is that this story is still very real today,” said Dr Loke Ming Chou, a tropical marine science professor at the University of Singapore, who said that “frenetic, makeshift and ad-hoc development driven only by profit” was a curse for these pristine beaches.

“After so many lessons of overwhelmed beach locations, the rush to make money still ignores the environment, which is what attracts tourists in the first place. This is not sustainable and such places will collapse when tourists stay away to avoid swimming in their own muck.”

This month it seems that governments are finally paying attention to a situation that is spiralling out of control. According to recent announcements, both Maya Bay and Boracay could be shut down for up to six months to give the environment a chance to recover.

In the Philippines, the president, Rodrigo Duterte, has called for Boracay’s temporary closure, comparing it to a “cesspool”. “You go into the water, it’s smelly,” said Duterte. “Of what? Shit. Because everything that goes out in Boracay … it’s destroying the environment of the Philippines and creating a disaster.”

In Thailand, where the ministry of environment has already banned smoking and littering in beachside locations, the mooted June-to-September shutdown of Maya Bay would be the most far-reaching attempt yet to get a grip on an industry that is both a money-spinner for the nation and an environmental menace.

Facebook Twitter Pinterest Leonardo DiCaprio in The Beach. Photograph: Allstar/Cinetext/20 CENTURY FOX

In the high season, Maya Bay, just 200 metres long, receives up to 5,000 visitors a day. About 300 speedboat trips are made here every day. Larger boats sailing round the islands also stop by the cove.

Although the beauty of the place is still evident, the atmosphere resembles a busy industrial port more than a paradise beach, with the endless roar of engines and the smell of petrol in the air. By 9am, as the speedboats continually pull up, the beach is so tightly packed with people that it resembles a mass game of sardines. Every patch of sand is fought for, especially by the optimistic few who risk lying down for a spot of sunbathing. People visibly duck to avoid the selfie sticks and umbrellas that fill the air like strange antennae.

Three uniformed national park police stand on the shore, blowing their whistles at the boats that park directly on the beach, obstructing the view of the bay. If tourists want to swim in the sea, there is a small area on the left side of the beach, where they are packed in as tightly as on the sand, many in orange life jackets.

Paradise? American tourist Chad Roberts certainly thinks so. “It’s amazing, better even than the pictures, I can’t believe how blue the water is,” he said. “I don’t mind all the people. Look, I come from the middle of America and we don’t have anywhere like this at home. Most beautiful place I’ve ever seen.”

But Spicey, who was born in Phuket and has been a tour guide for almost seven years, said she hoped the Thai government followed through on its pledge to close Maya Bay, even for a few months. “It needs just a small break to heal.” She spoke sadly of the destructive behaviour she has witnessed from the millions of tourists who come through Maya Bay on the island-hopping tours. The corals and fish that used to be visible when snorkelling have all but disappeared, she said, yet tourists still insist on taking bits of coral to feed the fish, which is illegal as it stops the fish cleaning the coral, causing it to die.

I see guys in the speedboats fix the oil and change the engine on top of the reef, and you can’t say anything to them Yass, tour guide

“Most people don’t care – they want to see the fish, so they feed them anyway,” she said. “All the tourists will try to take everything and see everything they possibly can in the short time, and they don’t really care about the cost to nature. I have had so many arguments with tourists, asking them not to take the coral.”

According to Spicey, most tour guides just let the tourists do what they want. “There is no respect, and the attitude of most tour guides is ‘it’s illegal but I will close my eyes’. It happens usually when the tour guides are foreign. We Thai tourist guides love our home. We want to protect it. But for foreign tourist guides, when they’ve earned enough they fly back to their home, what is left for us? Nothing.”

The local environmental authority has laws in place to protect Maya Bay and the surrounding national park, but the fines are so low – often only 500baht (£12) – that the rules are routinely flouted. A year and a half ago, a law was put in place that prevented boats throwing down anchors, and possibly destroying 10 years’ worth of coral growth in a single second. But Kezia, a diver who has spent the past year in Koh Phi Phi Don (the largest inhabited island on the Thai archipelago), said it still happens. “In low season last year we had this one big fancy boat that came to the national park every day for diving, and they just didn’t care about throwing down the anchor because the fine is not very much,” she said. “They just paid it every day and still used the anchor.”

There is still a reluctance by local authorities to prioritise the environment over profit. Maya Bay is a massive money earner. Every visitor has to pay 400baht (£10) simply to access the island, which can add up to a daily revenue of £50,000. According to another tour guide, Yass, temporarily closing Maya Bay is not enough. People must be taught to look after it if the place is to remain a beautiful tourist destination rather than become a ruined paradise. “I see the guys in the speedboats fix the oil and change the engine on top of the reef in the morning, and you can’t say anything to them,” he said. “It makes me so angry that they have all this beautiful landscape and they don’t educate people how to look after it.”

More than 1,600 miles away, Boracay – which, like Maya Bay, features on every list of paradise destinations – is grappling with the same problems. More than 2 million tourists flock to this five-mile-long island every year. Unregulated development has seen the rise of hotels, restaurants and food chains along the entire shoreline of its famed White Beach, which runs the length of the island. Inland is also covered with huge hotels. Everywhere, new construction projects are visible.

The sea is suffering as a result. An endless flow of sewage is pumped into the ocean, as well as detritus from the construction work. The sparkling clear waters seem pristine, but the huge destruction of coral over the past few years tells a very different story.

Jojo Rodriguez works for Sangkalikasan Producers Cooperative, an NGO that has been monitoring the state of Boracay’s reef since 2012. He believes the authorities “purposefully turned a blind eye” when it came to environmental issues that could threaten the tourist trade.

After a massive die-off of coral in 2015, local authorities threatened to declare Rodriguez persona non grata after he publicly linked the disaster to the sewage being pumped into the sea. He said intimidation tactics and threats have since been used against reporters and campaigners who have tried to speak out about the environmental damage. “All these huge profit makers don’t want anyone to get in the way – everybody is afraid to lose the tourism money,” he said, “and so we’re slowly losing Boracay.”

Facebook Twitter Pinterest A clownfish swims around some coral. Reefs around the world are being devastated by pollution, mass tourism, over-fishing and climate change. Photograph: Mumemories/Getty Images/iStockphoto

Many living on the island said that while there were technically rules in place to save the environment, bribes meant these were rarely upheld. “It’s really corrupt. If you have money, you can do what you want, build what you want here,” said Simone, the owner of a kite-surfing shop.

As in Maya Bay, boats are the great destroyers. On White Beach the entire horizon is filled with sailing boats, speedboats, jet-skis, yachts and traditional fishing boats, and a steady hum of boat engines fills the air. Fertiliser from the island’s vast golf course (built purely for tourists) is also a major pollutant of the coral, as are the mounting piles of rubbish that end up in the sea. Angie, a diver from Worcester in the UK who moved to Boracay five years ago, said they often came back from dives with bags of rubbish they have picked up off the coral.

Michael Martillano, president of the diving association on the island, is conflicted over Duterte’s declaration that he might shut down the island. “Boracay definitely needs some help,” he said, “but we shouldn’t all be punished for the few who are breaking the rules and causing the problems to the environment.”

He conceded that the marine life of Boracay is nowhere near as rich as it used to be. “The reef is now totally different from when I first started diving here in 1994,” he said. “You used to see a lot of sharks and barracudas, all the big stuff. Now you’ll see one, maybe two sharks if you’re lucky, nothing like before.

“And there used to be a lot of crustaceans, like lobsters, but now I see more in the market because there’s a real tourist demand to eat them. The island really needs help.”

Is there still hope for the island? “Boracay will never be the same again,” said Rodriguez. “The president said close down Boracay, but it’s not going to be solved in six months. For the island to heal itself? Maybe 60 years if we are lucky.”

In both Maya Bay and Boracay, a six-month tourist ban may not be nearly enough to solve an ecological crisis. That is certainly the view of environmental campaigners. But as the coral reefs of south-east Asia continue to die, it would be a start.