More than 40 per cent of homes in London are likely to be affected by subsidence by 2030 due to extreme weather, a report on how to prepare the capital for flooding and heatwaves warned on Wednesday.
The London Climate Resilience Review was commissioned by Mayor Sadiq Khan after the floods of 2021 and the 40C heatwave and wildfires of 2022. It makes a series of recommendations and says: “Now is the time for action.”
It warns: “Despite greater co-ordination of stakeholders since the floods of 2021, London is not prepared for another major surface water flooding incident and lives and livelihoods are at risk.”
The 169-page report says that subsidence is a “considerable climate risk” in London, with about 43 per cent of properties likely to be affected by the end of the decade.
The capital is “especially vulnerable” due to its clay soil, densely-packed homes and exposure to heat and drought.
Projections suggest the number of properties in London likely to be affected will rise from 20 per cent in 1990 to 43 per cent by 2030 and 57 per cent by 2070.
In recent years there has been a sharp increase in insurance claims. Subsidence happens when the ground beneath a property sinks, pulling the foundations down with it. Experts believe hotter and drier summers are causing soil shrinkage.
The report, by Emma Howard Boyd, a former chair of the Environment Agency, describes London as an area of “serious water stress”. It says summer water shortages increase fire risk, reduce the ability to fight fires and cause long-term damage to nature.
During the 2022 heatwave, operations were cancelled at Guy’s and St Thomas’ hospitals because IT servers failed. The East Coast mainline was disconnected from King’s Cross as train lines buckled. TfL lost £8.4 million in revenue as passengers shunned sweltering Tubes and buses.
More than 30 Tube stations were flooded during the 2021 deluge. The report said London needs a new reservoir, while the Thames Barrier will have to be replaced by 2070.
The report said: “London is underprepared, but not unprepared. Adaptation is taking place all over London, but now a step change is needed.”
Mr Khan said: “Climate change is one of the biggest dangers our capital faces, and its effects cannot be ignored.
“It is essential that we invest in key sectors and prepare our public services so that London can continue to grow and thrive in the face of climate change, and the review provides clarity and direction on how to do this. We do not have a moment to waste.”
Last month the capital’s emergency services and local authorities took part in a disaster-planning exercise, Operation Helios, to test what would happen in extreme heat that lasted for more than five days.
The report highlights examples of best practice in other cities around the world and suggests “urban nature-based solutions” such as street trees, sustainable drainage systems, green roofs and a return to 1950-style awnings offering shade over shop fronts.
Because of the “urban heat island effect”, the capital is often several degrees warmer than surrounding rural areas.
But there is a “low understanding” of the costs of severe weather and the benefits of preparedness.
Elderly residents are at greater risk from heatwaves. In 2022, there were 387 heat-related deaths in London.
The report says Mr Khan should set a vision for a city that is adapting well to climate change, and targets for reducing the number of homes known to overheat and the number at severe risk of flooding.
It suggests attaching the requirement to City Hall funding for all recipient organisations to consider climate resilience, and to provide incentives for utility companies to leave behind “SUDS” sustainable drainage beds after digging up roads.
Ms Howard Boyd, chair of the London Climate Resilience Review, said: “This is a reset moment for efforts to increase the UK’s stability in the face of global climate disruption.
“As the new government takes action to end the cost-of-living crisis, protecting the lives and livelihoods of working people from extreme weather is non-negotiable.”
