The coastal erosion conundrum

But five years on, the problem is far from being solved. Storms again washed away much of the sand last year, and new plans to raise the sea wall a further 2.5m to 7m were submitted in February this year.

"It's still a beautiful beach, though. It's possible much of the sand will return over time", says an optimistic Suzanne Papanicola, spokeswoman for the Hazelwood Holiday Park, which lies just behind the beach.

As sea levels rise, storms get stronger and the world's coasts become lined with development, cash-strapped governments and communities from Spain to Brazil and Australia to California are grappling with what to do with their crumbling sea defences.

The old assumption that stronger, higher walls can hold back the waves is being challenged by marine geologists who argue that building "hard" defences and removing natural barriers such as sand dunes and mangroves leads only to the disappearance of beaches, worse flooding and an endless cycle of expensive repair and reconstruction.

"The sea wall itself is the problem", says Andrew Cooper, professor of coastal studies at the University of Ulster. "It cannot absorb the energy of the sea. Sea walls cause beaches to steepen, which means that bigger waves with more energy reach the remaining beach, scouring out the sand and undermining the defences. The more that we build sea walls, the more we destroy our beaches

"If you build a sea wall to protect the shore, the inevitable consequence over time is that the beach will [eventually] disappear. When you build the sea wall, that is the effective end of the beach", he adds.

"Sea walls are the deadly enemies of beaches. We are obsessed with building and defending property right next to the beach and trying to hold the beach in place", says Orrin Pilkey, author, with Cooper, of The Last Beach and professor of earth and ocean science at Duke University in the US.

Pilkey, now in his 80s, has long advocated natural beaches where possible but says that the future of the world's coastlines is uncertain because the coast is inherently dynamic and changing. He despairs of the situation in the US, where beachfront developments mushroom and engineers lock cities into expensive projects to continually strengthen their defences. The only solution, he says, is to move development back from beaches altogether: "In its efforts to hold the shoreline still, today's society is engaged in a costly and ultimately futile battle. On the one side is the coastal engineering fraternity and on the other the inexorable forces of nature. Many beaches on developed coasts have been transformed into long, thin engineering projects. These strips of sand that we call beaches were once a precious natural environment that has been destroyed in a misguided view of the good of humanity."

Beach wear

The price paid for trying to hold the sea back with steel and concrete is seen all along American, European, Australian and increasingly, Asian coastlines. In Japan, where nearly 40% of the coast is now lined with massive concrete walls to guard against tsunamis, beaches are disappearing at an alarming rate. The government's Institute for Environmental Studies forecasts that a combination of rising sea levels and seawall construction threatens to completely wash away 60% of Japan's sandy beaches.
Some of the worst coastal erosion in Asia is taking place in Vietnam, where developers have rushed to build coastal holiday resorts. The result, in places such as Unesco World Heritage Site Hoi An, and cities like Da Nang, has been beaches disappearing and defences crumbling, and projected revenue losses to the tourism industry of nearly $30m.

In the US, where the government estimates there are around 350,000 structures located within 150m of the sea, nearly 14,000 miles (22,500km) – 14% of the entire coastline – has been fortified with concrete, according to a 2015 report from the Marine Science Center at Northeastern University. What were wide stretches of sand just 30-40 years ago are often now narrow strips of beach sited below high walls. Meanwhile, research published in June 2018 by the Florida Department of Environmental Protection found that almost half of the state's 820 miles (1,320km) of coastline are now "critically eroded". Most of the state's coastline is "defended" behind sea walls, which are partly responsible for the beaches' disappearance.

The worldwide response to eroding beaches has been to replenish them with dredged sand. This temporarily widens them and maintains beachfront property values, but is expensive and must be done frequently. Beach "replenishment" is now a booming global industry, with one academic study suggesting $100bn a year is spent restoring US beaches alone. Hundreds of US barrier islands off the coasts of North Carolina, New Jersey, Texas and Florida now need massive, regular supplies of sand. On Galveston Island in Texas, the beach has been raised up to 5m, and the ground floors of some buildings have been turned into basements.

Many cities now replenish their beaches every year to keep the tourist industry alive. California is estimated to have pumped 300m m3 of sand on to its beaches over the past 30 years, and Florida 230m m3. But as storms increase and demand for sand grows, the cost of replenishment is spiralling. The wealthy residents of Malibu's Broad Beach in California received approval last June to add 300m m3 of sand to their short length of coastline at five-year intervals for the next 20 years. It is expected to cost them $31m.
They might be wasting their time. Geologists warn that sand replenishment actually worsens the erosion. "These artificial beaches usually erode at least twice as fast as natural beaches and can only ever be a temporary solution. As time goes on and as the sea level rises, the interval of replenishment will get shorter because the beach becomes less stable," says Cooper. "Beach replenishment is only a plaster that must be applied again and again at great cost. It doesn't remove the problem, it treats the symptoms. Eventually and inevitably beach replenishment will stop, either as sand or money runs out."

Replenishment also smothers all life on the beach, adds Pilkey. "The near-shore food chain that originates with the tiny organisms living between grains of sands and surviving on occasional influxes of seaweed is now gone. The whole ecosystem is out of whack. Habitats for turtle and bird nesting are being destroyed."

The powerful American Shore and Beach Preservation Association (ASBPA), the leading advocate of beach replenishment, condemns both sea walls and letting nature take its course. "Centuries of coastal development and engineering coastlines and inlets have caused much of the coastal erosion we see today. Sea-level rise will only make this worse. There is no way to now let nature take its course without reversing the events of the past 300 years," says Asbpa director Derek Brockbank. "Replenishing the sand that is lost is a critical tool to maintaining healthy coastlines. It costs money, but it is preferable to the cheaper – but ecologically destructive – alternative of building sea walls to protect coastal property."

British beaches are some of the most heavily eroded in the world. Government subsidies to maintain hundreds of miles of sea walls, groynes, artificial beaches and breakwaters cost more than £750m a year. But this has not stopped flooding, or beaches in places like Ventnor on the Isle of Wight, Lowestoft in Suffolk and Aberystwyth in Wales being eroded. The Welsh Environment Agency calculates that there are 220,000 properties, housing 357,000 people, at risk of flooding in Wales. Just to maintain this level of risk would require spending on defences to be tripled in the next 15 years.