Improving spatial assessment of vulnerability to urban heat stress: Developing a Heat Vulnerability Index for Greater Manchester

  • Charlotte Brown

Student thesis: Phd


UK average summertime temperatures have increased over the last 20 years. Climate change is also projected to cause increases in average and extreme summer temperatures. High temperatures have a number of associated negative impacts for individuals. Heat stress among humans can cause both mortality and morbidity. The UK experiences regular heat related excess mortality. Moreover, warm temperatures have also been associated with a lack of sleep and lower productivity at work. Overheating in homes, contributes to these negative effects by exposing individuals to higher temperatures. Overheating is an emerging problem for the UK housing stock, which is maladapted for rising temperature. Furthermore, cities are a place of elevated risk due to the added pressure of the Urban Heat Island effect. A number of adaptation measures can be used to reduce the negative impacts associated with heat. However, vulnerability to heat varies significantly among individuals and is a result of many interlinking factors. Socio-demographic characteristics, health, economic status, an individual’s home, and where that homes is located can all modify their vulnerability. Understanding this vulnerability is paramount to successful adaptation and building resilience. Tools such as Heat Vulnerability Indexes or other spatial vulnerability assessments can help to identify spatial patterns of vulnerability and where the most vulnerable people reside for prioritisation of adaptation and responses during high temperatures. This thesis improves the process of developing such assessments by addressing three specific gaps which are identified in past studies and using Greater Manchester as a case study. It firstly improves the way in which intra-urban outdoor exposure variation is spatially represented in these assessments. Land use regression modelling is used to replace past over reliance on land surface temperatures. Empirical air temperature data and 14 different land use and land cover variables were used to create statistical models of air temperature. These were used to predict air temperature; these predictions were in turn used within the Heat Vulnerability Index. This greatly improved the way in which local variations of outdoor exposure are assessed. Models with an R2 of over 0.9 and RMSE of as low as 0.13 °C were developed. Next the work addresses a second gap, namely the underrepresentation of homes as a modifier to heat vulnerability within indexes. To do this, firstly a specific review of overheating in homes is presented, this provides a concise overview of the current knowledge of overheating in homes, and identifies characteristics of homes which have been highlighted by other studies to increase the homes propensity to overheat. These characteristics are then used to assess the risk of overheating spatially across the area. Here, a novel method of mapping these characteristics is presented and the results for GM are discussed. Finally, improvements are made upon past methods of constructing composite indexes, presenting a method that better and more transparently deals with co-variance within the indicators, and used an evidence-based approach to indicator weighting. Overall, a Heat 18 Vulnerability Index for Greater Manchester is developed and presented using novel indicators and an improved method of index construction. The index assesses vulnerability at the census unit of Lower Super Output Area, across the metropolitan region of Greater Manchester. This index shows large spatial variation in overall vulnerability across the region, as well as spatial differences in the drivers of vulnerability. The local authorities of Manchester and Salford are highlighted as particularly vulnerable.
Date of Award31 Dec 2022
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorSarah Mander (Supervisor) & Ruth Wood (Supervisor)


  • Spatial risk assessment
  • Urban Heat resilience
  • Climate Change
  • Climate vulnerability

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