Britain is preparing for yesterday’s weather while tomorrow’s climate has already arrived. That is the stark warning from the Institution of Mechanical Engineers and the UK Infrastructure Operators Adaptation Forum, in new research published today, ‘Preparing the UK for More Extreme Weather’.

The report reveals that the biggest threat is no longer a single flood, heatwave or storm, but what happens when one extreme event follows another or an infrastructure failure in one sector triggers others elsewhere. The UK must rethink how it protects the essential services millions of people rely on as climate change brings more frequent, severe and unpredictable extreme weather.

Heatwaves can hit infrastructure from both sides, reducing power capacity while sending demand for cooling soaring. A power failure can then knock out communications, digital services, food supply and even healthcare. Yet much of the UK’s infrastructure is still designed around individual hazards and yesterday’s weather, leaving it vulnerable to increasingly unpredictable extremes.

The biggest risk we face may not be one extreme event, but several occurring in series and many things going wrong at once – particularly the failures that cascade from one system into another.
Dr Tim Fox CEng FIMechE, Chair of the IMechE Climate Change Adaptation Working Group

Five things Britain needs to do now

Stop designing for yesterday’s weather: Stress-test new and existing infrastructure against plausible future extremes, including combinations of heat, flooding, drought and storms.
Prepare for everything going wrong at once: Government and infrastructure operators should run regular cross-sector exercises to test how failures could cascade across energy, water, transport, food, healthcare and telecommunications.
Find Britain’s weak links: Map critical dependencies on power, water, digital systems, transport, suppliers and the workforce, and remove single points of failure wherever possible. The NHS has already used systems mapping to identify how climate risks could cascade through data centres, telecommunications, energy and healthcare, leading to practical measures such as backing up critical data across different locations.
Invest before disaster strikes: Funding and regulation should allow investment in resilience before extreme weather causes failure, rather than waiting for disasters to demonstrate the need. Glasgow shows the benefits of taking a whole-system approach, with investment delivering flood protection, better water quality, urban improvements and greater climate resilience.
Build infrastructure that can adapt: Design major infrastructure so it can be strengthened or modified as climate risks change, with clear triggers for action. The Thames Estuary 2100 plan shows how this can work, using monitoring and decision points to determine when further flood protection is needed rather than committing to one solution decades in advance.

Dr Tim Fox CEng FIMechE, Chair of the IMechE Climate Change Adaptation Working Group, said: “The biggest risk we face may not be one extreme event, but several occurring in series and many things going wrong at once – particularly the failures that cascade from one system into another.”

Our infrastructure is increasingly interconnected. If the power goes down, what happens to the water supply and refrigerated food? If transport is disrupted, can essential workers get to hospitals? If a data centre fails during extreme heat, can vital services across multiple sectors continue?”

Denmark’s rail operator Banedanmark is using sensors, asset data and lessons from incidents and near misses to understand when infrastructure performance is beginning to deteriorate, allowing investment decisions to respond as risks evolve.

At Heathrow, complex climate projections are being turned into realistic scenarios showing operational teams how extreme weather could affect the airport – and what they can do about it.

Dr Fox added: “These approaches demonstrate a new model of resilience. We cannot predict exactly what the climate will look like decades from now. But we can make sure our infrastructure is capable of responding when conditions change.

“The question is no longer simply ‘Can this asset withstand a flood or a heatwave?’ It is ‘Can the system continue to provide the service people depend on when several things go wrong at once?”