Millions of homes in London, Essex, Kent, and a scenic strip from Oxford up to the Wash are at risk of sinking, thanks to climate change making the ground act like a dehydrated sponge. That's according to the British Geological Survey (BGS), which has apparently been studying dirt with great concern.

As hotter, drier summers become the new normal, the ground under houses shrinks and drags down foundations - a phenomenon scientists call "shrink-swell subsidence." Anna Harrison, a BGS scientist, describes it as a "double whammy": London gets both the worst soil shrinkage and the biggest temperature and rainfall changes. Also, it's full of buildings.

"These properties might have foundations that currently can withstand the changes in moisture," Harrison said, "but you might find in future there’s going to be more movement. It’s probably going to get worse."

Subsidence is not just a geological party trick - it can tank a property's value, make lenders refuse mortgages, and leave you with diagonal cracks around your windows and sloping floors. Fixing it may require engineering work, replacing utility pipes, and removing trees. Fun.

In 2025, the UK had its warmest spring on record and its driest in over 50 years. Insurance companies paid out £153 million in subsidence-related claims in just the first six months. By 2070, under a low emissions scenario (the one where we actually follow the Paris climate agreement), about 500,000 properties could be affected. Under a medium scenario - which is basically where we're currently headed - that jumps to over 1.8 million properties.

London boroughs like Camden, Islington, and Barnet are most susceptible, with more than 26% of properties in the capital expected to be affected by 2070 under medium emissions. So if you own a home in London, maybe start saving for underpinning now.