In partnership with AtkinsRéalis

After years of discussion and predictions about climate change, we are now witnessing its devastating effects on communities and the transport networks that connect them.  

Last year, the UK experienced its wettest 18 months since records began, with parts of the country recording double the average levels of rainfall, whilst the start of May 2025 brought the highest temperatures for the time of year since records began. These extremes are impacting both the strategic and local road networks as much as any infrastructure, and with varying degrees of severity. From the inconvenience of disruption to journeys due to road closures or damaged assets, to long-term economic impact or the risk of endangering life, the myriad of challenges presented by climate change are real and are here to stay.  

From an international perspective, it’s highly likely global temperatures will surpass the 1.5 degrees Celsius stretch target from the Paris Agreement this decade, the threshold at which scientists agree we will start experience more extreme impacts of climate change.  In the UK, wetter, warmer winters and dryer, hotter summers are rapidly replacing the expected seasonal norms.  What were once considered extreme weather events, are now occurring far more frequently with all parts of the country experiencing the effects of intense storms, heavy rainfall, high winds and changing temperatures.  

While other countries have the geographical expanse to design their infrastructure with climate forecasts in mind, in Britain we are faced with a greater challenge of embedding resilience into legacy infrastructure. As a small island with many urbanised and densely populated areas of the country, our transport infrastructure is largely in place, therefore we don’t have the capacity to build our way out of, or avoid, the problem. Instead, we are dealing with aging roads infrastructure - the majority of which was constructed more than 50 years ago. This is compounded by the Victorian drainage infrastructure in most of our major cities, including London and Glasgow which is now 150 years old and is struggling to cope with modern demands – including the increased risk of flooding.   

If there’s a silver lining, it’s the urgency that such events generate, prompting local and central authorities alike to focus their attention on adapting infrastructure and embedding resilience to climate change. Yet while the will is there, many decision-makers are ill equipped to address these challenges. Local authorities are less likely to have the resources necessary to prepare, expertise is lacking in house, and many climate change staff are seconded into their roles. National Highways and Transport Scotland are far better placed to protect the whole strategic road network, but road users do not distinguish between local and national - and severe problems on one part of the network cascade into others. 
 
As well as lacking capacity and resources, there is also a lack of knowledge. In order to understand which roads will deteriorate from repeated flooding, you need to understand the baseline of current risk and exposure. Moreover, different weather events will require different data points. However, asset data is another huge challenge, with uneven maturity across various authorities, and some that do have the data describe themselves as ‘data rich but insights poor’. 

These are significant problems, and in an ideal world we’d have time to work our solutions. But the situation is urgent.

Flood and thunder

In summer 2024, we were inundated with a month’s worth of rainfall in a single night, closing parts of the SRN and local road network. Extreme weather events such as this divert traffic onto other roads, causing congestion due to increased volume of traffic, with road users and communities inadvertently affected and roads authorities under resource pressure to manage the emergency. 

Maintenance crews are called out, working in difficult conditions to alleviate the flooding, and exposing themselves - and the authorities - to increased risk. These impacts sap the efficiency, flexibility, and productivity of the local and national economy. And unless we improve our baseline understanding of our assets and how the network behaves in response to extreme weather, we will fail to ‘anticipate’ the threat, unable to unlock the ability to do anything about it. 
 
There is a growing awareness of the need for action. The Department for Transport (DfT) recently published (March 2025) Climate Risk Assessment Guidance for the transport sector to help organisations understand the current and future effects of climate change and how to prioritise climate change adaptation, providing a more coherent and consistent approach.

Umbrellas for rain or shine

Building resilience into our roads depends on how well we understand the impact of extreme weather to our transport networks, communicate those impacts, and inform decision-making with the insights. The key is to illustrate the true impact of current and future weather events on our roads: highlighting the real breadth and depth of climate-related impacts, so that the business case for action becomes clearer. 

It starts by understanding the current impacts of weather events on the road networks, response and maintenance plans, and the decision-making structures that direct investment and resources. Then, modelling future climate scenarios on those networks and using these insights to uncover the ‘adaptation gap’ – how current response, maintenance and decision-making processes will fair in these future scenarios, and the resulting impact on the safe running, operation and cost of the network.  This provides the case for change in approach, and it is not necessarily about spending more now, rather about how, where and when investments are made to maintain the integrity of networks.  This means that adaptation starts with a small investment in understanding future climate risks, determining cost-benefit of action and directing investments, rather than future proofing everything at once.  
 
Transport Scotland’s trunk road adaptation plan offers a valuable case study into the potential benefits of such an approach. As the most sparsely populated region of Britain, many of Scotland’s remote communities are more reliant on trunk roads to connect them to the wider world, and therefore more vulnerable to closures. Transport Scotland sought to strengthen adaptation and resilience by assessing the risks to its trunk road network to future climate and develop a strategy for reducing such risk. AtkinsRéalis were chosen to undertake the climate risk assessment, analysis and options for the plan. 
 
We proposed options for adaptation based on the most fundamental outcomes: Safety, Resilience and Reliability. We analysed high-level financial, social and economic costs associated with weather-related events and the impacts downstream. This included considering the wider impacts such as additional maintenance burden caused by diversions onto auxiliary roads. As well as flooding, heavy rainfall can also raise the risk of landslips. Combining datasets for topography, weather conditions, and asset maintenance, our Washout Vulnerability Assessment Tool assessed which embankments are most likely to subside following heavy rain. This flagged the most at-risk parts of the network and enables the transport authority to make informed decisions on where and when investment is most needed. 

A forecast for change

The climate change challenge may seem overwhelming and, with various levels of understanding and maturity across the UK, it may appear a difficult and solitary journey.  But we can anticipate the potential impacts of climate change, make the case for change, adapt and withstand and recover from weather events that are becoming the norm.  And, with coordination from DfT, the sharing of best practice and development of guidance and methodology, we can now work together today to reduce the risks of disasters tomorrow.

About AtkinsRéalis:

AtkinsRéalis is a world-class engineering services and nuclear company dedicated to engineering a better future for our planet and its people. We create sustainable solutions that connect people, data and technology to transform the world's infrastructure and energy systems. We deploy global capabilities locally to our clients and deliver unique end-to-end services across the whole life cycle of an asset including consulting, advisory & environmental services, intelligent networks & cybersecurity, design & engineering, procurement, project & construction management, operations & maintenance, decommissioning and capital. The breadth and depth of our capabilities are delivered to clients in strategic sectors such as Engineering Services, Nuclear and Capital. 
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