Spatial Climate Risk Assessments: A tool for understanding future risk and adaptation planning

Climate change is one of the biggest challenges of our generation and has already begun to cause irreversible damage to our planet. For example, increasingly high temperatures, such as those experience in the UK 2022 heatwave, are affecting health and well-being, leading to increased mortality, challenging conditions for care services supporting the elderly and vulnerable, and disruption to transport due to infrastructure failures. Climate projections indicate that these conditions are going to increase in frequency and severity with climate change, meaning the related impacts will become increasingly common in the UK and throughout the world. 

For individuals, organisations, and governments to make informed decisions about how to adapt to climate change, it is important to not only quantify how the meteorological conditions (the hazard) may change, but how this translates into a change in risk. 

Assessing Climate Risk  

One approach for quantifying climate risk is to use a form of quantitative risk assessment framework, often known as a catastrophe model in the insurance sector. Similar to the Intergovernmental Panel on Climate Change (IPCC) definition of risk, these frameworks combine information about the hazard (e.g. extreme wind during a storm), exposure (e.g. the location of assets) and vulnerability (e.g. the structural integrity of the assets) to compute metrics necessary for assessing risk (e.g. financial loss due to asset damage).  

These frameworks allow for the change in risk resulting from climate change to be quantified, helping to inform organisations and governments about relevant planning and adaptation decisions to reduce future risk. An additional advantage of such frameworks is their consideration of risk in a spatially consistent way, i.e. capturing all relevant locations in a space coherently together. This is particularly important for stakeholders with spatially distributed assets, such as government organisations with buildings located across the country (e.g. schools) or companies with people or assets in multiple places (e.g. offices and production facilities). 

Risk assessment frameworks have been developed and used within the insurance and reinsurance sectors to quantify financial risk for many years. In more recent years, however, an increasing number of publicly available, open-source risk assessment frameworks have been made available. Examples include CLIMADA, the Oasis Loss Modelling Framework, and RiskScape. These allow flexibility in the quantification of risk, specifically enabling their application to non-financial risk quantification, such as health. 

The UK Climate Resilience Programme 

As part of the UK Climate Resilience Programme, the Met Office have developed a novel extension and application of the CLIMADA risk assessment platform.  

The first part of this work applied the CLIMADA platform to an ensemble of UKCP18 Regional Climate Model (RCM) projections to assess climate risk coherently across space, and used data science modelling techniques to provide a richer quantification of climate model uncertainty. Within this first study the framework was applied to an idealised example related to the effect of extreme heat and humidity on outdoor labour productivity in the UK. This found that the UK could lose 15 million working days per year to heat stress in a 2°C warmer world, representing more than £1.5 billion in economic losses, with this risk becoming 2-3 times greater if warming reaches 4°C. 

Further, as undertaking a risk assessment requires making many subjective choices, such as which hazard, exposure and vulnerability data to use, alternative options should be considered to understand the uncertainty and sensitivity of risk to these input choices. A second study therefore aimed to explore the uncertainty and sensitivity of climate risk to labour productivity by varying the way in which the hazard, exposure and vulnerability were defined in the risk assessment. This study highlighted the sensitivity of risk to the global warming level considered and hence importance of mitigating climate change to reduce heat stress risk (i.e. to reduce the likelihood of a 4°C warmer world). It also showed that the risks posed by climate change can be dependent on differing factors across the UK, requiring targeted local adaptation action. 

Planning and Adaption for Policy Makers  

In the UK, the government is required to undertake a Climate Change Risk Assessment (CCRA) every 5 years, to assess risk, understand adaptation priorities and measure progress in adapting to reduce climate risk. The third UK CCRA (CCRA3) was published in 2022. This highlighted the limited progress that had been made in addressing the increasing risks from overheating in UK houses, health and care facilities, schools, and prisons. In addition, it hypothesised that policies to address Net Zero may increase the risk of overheating and hence emphasised the need to tackle the full range of building interventions in a holistic manner. 

Following CCRA3, the third UK National Adaptation Programme (NAP3) was published in July 2023. This sets out the actions that government are planning to take to adapt to the impacts of climate change over the period 2023-2028. As part of this programme, government departments have committed to undertaking research to better understand climate risk and to take adaptation action to reduce this risk. 

As part of this, the Met Office are currently working with the Department for Education (DfE) and building scientists at University College London (UCL) to assess the impact of heat on loss of learning in schools. The CLIMADA-based framework is being applied to the world leading high resolution 2.2km convection-permitting model projections, recently updated as part of UKCP18, combined with school building stock modelling from UCL and DfE building condition data (Condition Data Collection 2) to assess current and future indoor temperature risk in schools and inform DfE policy planning. 

Future Scope 

The spatial climate risk assessment framework developed and applied in this work can be applied to any region, hazard or risk metric of interest (provided suitable data is available). For example, it could be used to assess the financial risk of future flooding; the health risk associated with extreme heat; the risk of infrastructure damage in the energy sector; or the future risk to crop yield due to changing temperature and rainfall patterns. In future work, the Met Office are aiming to explore these applications to further support government and industry in understanding and adapting to climate risk.