At the Trump Doonbeg golf course on Ireland’s west coast, the ocean has been inching closer to a private bar overlooking the 18th hole. Since the links opened in 2002, waves crashing on the edge of the greens have swallowed about a meter of beach each year.

Some 808 miles (1,300 kilometers) away in Denmark, a century-old lighthouse was moved inland from a retreating shoreline, while in Portugal, authorities may tear down buildings along 76 miles (122 kilometers) of an eroding coast. And like the village of Fairbourne in northern Wales, the French holiday town of Lacanau is considering relocating part of the community inshore.

Across Europe, the sea is encroaching on nearly a fifth of the coastline, the European Union estimates, eating away landfills, stripping sand from beaches and bringing ecological, economic and human pain. Climate change will only accelerate those losses.

The world may lose almost half of its sandy beaches by the end of the century if climate change isn’t kept in check, according to a study in Nature Climate Change this month. The study assumes a 7.2 Fahrenheit (4 degree Celsius) increase in temperatures from preindustrial levels by 2100 that would raise sea levels, leading to erosion and increased coastal flooding.

“A sea level rise means there’ll be an acceleration of erosion,” says Bruno Castelle, a researcher at the University of Bordeaux. “Rising sea levels are a certainty, the magnitude much less so. In any case, we’re headed for increased vulnerability.”

While coastal erosion is a global phenomenon, Europe is especially exposed, with the highest ratio of shoreline to total land area of any continent. Economic development and booming seaside tourism have led to a build up of Europe’s littoral in the past five decades, transforming marginal coastal lands into hot property.

The value of assets within 547 yards (500 meters) of the EU shoreline was estimated at as much as $1.1 trillion (1 trillion euros) in a 2009 study by the European Commission. Damage from coastal flooding and erosion under a medium-to- high carbon-emission scenario may reach $12.4 billion (11 billion euros) annually in the next 30 years and $28 billion (25 billion euros) by 2080, an EU-funded report says.

With sea levels rising about a tenth of an inch (4 millimeters) a year along some parts of the continent, vulnerability is increasing. Already, 42 out of 49 Unesco World Heritage sites in the Mediterranean-including the ancient Italian city of Syracuse and the Maltese capital Valletta-are at risk.

In France’s Soulac-sur-Mer, the sea washes up to the foot of the now-abandoned five-story Le Signal apartment building constructed more than 219 yards (200 meters) from the ocean in 1967. In Brittany, the erosion affecting 35% of the coast appears to be accelerating, the Journal of Coastal Research said last year.

Catalonia’s beach capacity may shrink by nearly half by 2050, scientists estimate. On Crete, where 90% of tourism is attributable to beaches, researchers found about 70% of beaches in retreat. In the Aegean archipelago, rising seas may be “devastating,” entirely washing away up to 88% of beaches by the end of the century, according to a 2017 Greek study.

The European Commission’s Green Deal presented in December failed to mention either marine erosion or rising sea levels. The bloc’s last comprehensive report on what’s whittling away European shores, called Eurosion, dates to 2004. EU spokeswoman Ana Crespo Parrondo said erosion data “is not readily available.”

Erosion “is an incredibly underrated problem,” said Jeroen Aerts, a professor who heads the water and climate risk unit at Amsterdam’s Vrije Universiteit. “Due to sea-level rise and coastal erosion, in the future, small storms will have as much impact as major storms now.”

Storms such Ciara and Dennis that battered northwest Europe in February accelerated the wearing down of the coast, carrying off chunks of beach and causing cliffs to collapse along the English and French seaboards.

January’s storm Gloria hit Spain hard, destroying the Petroli bridge near Barcelona and making beaches disappear. The Ebro delta was virtually wiped out, and rice fields were flooded with salt water.

Efforts to address coastal erosion with measures such as sea walls or sand fills can be expensive and are often short-lived. A million tons of sand pumped up to protect the Bacton Gas Terminal on Britain’s North Sea coast will hold just for 15 to 20 years. The Dutch, whose low-lying country is uniquely vulnerable to a sea-level rise, supplement their shores with around 16 million cubic yards (12 million cubic meters) of sand every year to keep up with what nature washes away.

“They are holding the line, but it comes at quite a cost,” said Robert Nicholls, a professor of coastal engineering at the University of Southampton. “Not that the Dutch can’t afford it; it’s quite a rational thing to do.”

But even in the Netherlands, whose wealth and history of wrestling the sea make it among the best prepared for rising waters, the erosion fight has its limits, says Marjolein Haasnoot at Deltares. Should the melting of Antarctica’s ice sheet trigger a worst-case scenario of sea-level rise, the Dutch may need 20 times as much sand to replenish what the sea takes away.

Researchers have linked accelerating erosion in recent decades to human activity, such as a breakwater extension at the entrance of Portugal’s Aveiro lagoon shrinking beaches to the north and south, or waterfront construction on Greek islands causing sand to wash away from the pocket beaches that are tourism hot spots.

Local protection measures such as sea walls or dikes to trap sand can shift the problem elsewhere, with the Eurosion report finding 63% of newly eroding coastline was located less than 19 miles (30 kilometers) from coastal engineering works.

Structures like hydropower dams and paved-over land mean rivers such as the Rhone and the Rhine carry less sand and clay to the sea, so there’s less material to replenish beaches. In France’s Camargue area in the Rhone River delta, the beach east of Saintes-Maries-de-la-Mer village has retreated about 500 meters over a century, partly as dams reduced the river’s sediment flow.

“Anthropogenic causes need to be addressed directly, because it will only get worse with sea-level rise,” said Athanasios Vafeidis at the University of Kiel.

The Trump golf course in Ireland, meanwhile, is seeking permission for coastal defenses like a sea barrier to keep the beach from being washed away. Some campaigners against the plan propose an alternative-move the golf course inland.

“Retreat will definitely be one option, but people are not yet prepared for it,” Vafeidis said.

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With assistance from Bloomberg’s Samuel Dodge, Laura Millan Lombrana, Eleni Chrepa, Morwenna Coniam, Aaron Eglitis, Jasmina Kuzmanovic and Christian Wienberg.