(Bloomberg) --When Bernard Weisse first noticed a tiny crack in the outer wall of his house on the outskirts of Paris, he dismissed it as little more than a nuisance. But in the four years since, a spiderweb of fissures has spread from floor to ceiling and snaked into virtually every corner of his home.
"We can hear loud cracking noises especially when it's warm outside," said the retired salesman and father of three. "Sometimes, I think we should get all our stuff together and leave."
Like a growing number of people around the world, Weisse is grappling with subsidence — a term for the sinking land that's causing damage to homes and other structures built on it. The slow-moving climate disaster has already caused tens of billions in damage and has the potential to affect 1.2 billion people in areas accounting for more than
While groundwater extraction, mining and earthquakes also cause the ground to shift, global warming vastly increases the risks. What happens is that soil swells with winter rain and then shrinks as it dries in the heat, cracking foundations in the process.
Because of its soil and its status as the world's fastest-warming continent, Europe is particularly exposed. The European Central Bank estimates the region's potential damage from sinking land at more than
For Weisse, the cost for repairs could climb to as much as €200,000 to keep his two-story home from crumbling. That would be part of the estimated €43 billion in damage that households face by 2050 in France alone, according to insurance trade group France Assureurs. With that much money at stake, it's set off a battle over who will ultimately have to pay.
Weisse's town of Presles-en-Brie has teamed up with 14 nearby villages and sued the state to have their subsidence issues recognized as a natural catastrophe like flash floods and wildfires. That would trigger payments from insurers and the government, powerful opponents for the municipalities.
"It's David against Goliath," said Dominique Rodriguez, who's been mayor of the pastoral community of 2,300 people for more than three decades.
So far, the big guys are winning. In Presles-en-Brie, at least 40 homeowners have sought subsidence compensation since 2020, and while two houses were granted CatNat recognition, others were rejected.
Europe is the epicenter because of its clay-rich soil and relatively high population density. Also, buildings from the 1970s and 80s — when a postwar housing construction boom was still underway — are particularly susceptible.
While Presles-en-Brie is an early victim, the issues are global. Jakarta has sunk more than 2.5 meters (8 feet) in a decade, and Tehran drops as much as 22 centimeters a year. In the US, Houston is most affected, with 40% of the city subsiding more than half a centimeter a year.
More than 425,000 Dutch houses will be exposed over the next decade, with subsidence already lowering house prices by as much as 5%, according to a
"The situation is urgent," said Karsten Klein, director of advocacy at Vereniging Eigen Huis, a Dutch homeowners association. "Waiting until homes become uninhabitable is not an option."
In London, shifting ground levels over the next five years are set to affect two-fifths of the housing stock, or more than a million homes, according to the British Geological Survey.
Across the UK, there have been a half dozen "surge years" for subsidence over the last two decades. With the country experiencing one of its driest springs in a century, 2025 could end up as another "
Insurance claims for the hazard jumped 78% between 2019 and 2023 and the average payout rose 40% over that period, according to data provided by the Association of British Insurers.
While the UK is one of the few countries in the world where insurers cover subsidence damage, it's tricky to manage because the impacts can be affected by local conditions like trees soaking up water. A few years ago, central London suffered the most from subsidence, but now it affects eastern neighborhoods more, according to satellite data from Value.Space.
Geobear says its data supports the shift of the subsidence burden to eastern London, where the surface is less built up and so more exposed. If movements are related to clay shrinkage, then it makes sense that places like Barking are hit harder, said Otso Lahtinen, Geobear's chief executive officer.
In France, half of all single-family homes could be affected by subsidence by the end of the decade, according to Paul Esmein, head of the French insurance lobby. Since 2016, the country's insurers have paid about €1 billion a year for subsidence claims. That amount tripled in 2022, when European temperatures hit their second-highest level.
To cope with rising losses from natural disasters and provide protection for homeowners, France launched a public-private insurance program in 1989 called CatNat — a system that puts the state and the industry on the same side as costs surge. Homeowners are compensated for damage after their municipality has been awarded a CatNat certification. Otherwise, insurers are free to reject claims.
Despite the challenges faced by communities like Presles-en-Brie, France's system is close to a best-case scenario for homeowners, which have little to no recourse to have subsidence damage covered in most other countries.
"Since its creation, the French system for recognizing natural disasters has constantly adapted to the damage suffered by the population," the French interior ministry said in response to Bloomberg questions, adding that the criteria for subsidence recognition was relaxed last year.
In the case of Presles-en-Brie, the interior ministry said natural disaster conditions was recognized for part of 2020 as soil moisture was determined to be abnormal. It didn't comment on the ongoing dispute.
Allianz France says that over the last decade subsidence constituted 60% of all CatNat damages in the country, almost double the rate of the previous 15 years.
"The trend is getting more complicated with climate change," said Pierre Vaysse, chief underwriting officer for property and casualty at the French insurer. "The forecast is that claims will at least increase by 50% and probably double by 2050."
France's CatNat system lost €49 million in 2024, its eighth straight annual deficit. Known as the Central Reinsurance Fund, the program is paid for by a national surcharge on insurance policies, which was
For homeowners, the strained system means higher premiums but with no certainty of coverage, and there's a risk that insurers abandon vulnerable areas as has happened in parts of the US prone to hurricanes and wildfires.
Potential repairs include foundation reinforcements known as micropiles and injecting compounds into the soil to stabilize the clay. In some cases, the costs can approach the value of the home. With selling hardly a viable option, owners have little choice but to fork out the money themselves.
"There is a real threat that the damage will end up dislocating our entire house," said Weisse, the owner of the damaged house in Presles-en-Brie.
Burdened by the impact of climate change, the insurance system is "on its last legs," said Regis Thauvin, who handles subsidence issues for the town council and is also affected. "We can't just tell people to wait a year and a half for a decision to be made before doing the necessary work."
The legal fight with the state has been going on since late last year and the towns, which represent about 72,000 people in total, are still waiting for a court date. As of early June, the government hadn't sent experts to review local damage.
The municipalities are prepared to take their case to the European Court of Human Rights if they lose, according to Rodriguez, the mayor of Presles-en-Brie.
"We have little hope that our legal appeal will eventually succeed," he said. "But the residents welcome our action and the fact that we're at least trying to make ourselves heard."
To contact the authors of this story:
Claudia Cohen in Paris at
Gautam Naik in London at
Tom Fevrier in London at
