Millions of homes across London, Essex and Kent are at risk of sinking as hotter, drier summers driven by global heating cause the ground to shrink and drag their foundations down, according to new analysis by the British Geological Survey (BGS).
The most vulnerable areas include large swaths of the capital, a tranche of land from Oxford up to the Wash on England’s east coast, and the counties of Essex and Kent. Scientists warn that mitigation measures will be needed urgently.
“Millions of homes in London, Essex and Kent at risk of sinking due to climate-driven ground shrinkage, BGS warns.”
Anna Harrison, a scientist at the BGS, said: “By combining geotechnical information about volume change potential with data about projected rainfall and temperature scenarios for the coming century, we have been able to identify the areas of Great Britain most likely to become susceptible to shrink-swell subsidence.”
The problem is particularly acute in London, where a high density of buildings sits on clay-rich soil. “Most are in the London area and that’s also where you’re going to see bigger changes in rainfall and temperature. It’s a double whammy,” Harrison said. “These properties might have foundations that currently can withstand the changes in moisture, but you might find in future there’s going to be more movement. It’s probably going to get worse.”
Subsidence can slash a property’s value and lenders often refuse mortgages until repairs are made. Signs include diagonal cracks around window and door frames, and sloping floors. Fixing it can require engineering work to stabilise land, underpin the building, replace utility pipes, or even remove trees and vegetation.
The threat is already materialising. In 2025, the UK experienced its warmest spring on record and the driest in more than 50 years. Insurers paid out £153m in subsidence-related claims in the first six months of that year alone.
Looking further ahead, the BGS dataset forecasts that by 2070 about 500,000 properties could be affected under a low emissions scenario aligned to the Paris climate agreement. That figure rises to more than 1.8m properties under a medium scenario, which is closest to current global emissions trajectories.
Highly populated parts of London are particularly susceptible: Camden, Islington and Barnet top the list. Under the medium scenario, more than 26% of properties in the capital could be affected by 2070.
“Dry weather and high temperatures are a major factor in the emergence of shrink-swell subsidence,” Harrison said. “Looking ahead, these increases in hotter, drier summers and warmer, wetter winters …” – the message from scientists is clear: without action, the ground beneath millions of homes may literally give way.