Keywords

Introduction

As a consequence of the high concentration of population, services, and infrastructure, the impacts of climate change will be felt harshly in the urban scenario. The Urban Heat Island (UHI) effect exacerbates climate aftermaths. This brings significant technical challenges to ensuring the thermal comfort of an aged residential stock. As climate change becomes a determining factor in urban planning, new policies are being developed to anticipate its effects. While previous EU policies for buildings focused on energy efficiency, “the need for climate change adaptation in buildings is increasingly reflected in the EU policy landscape” (EC, 2023a, 3). This need has been singled out in the European Green Deal, specifically in the EU's Renovation Wave Programme. As a mitigation strategy, energy efficiency of buildings prioritises those contexts with the highest energy consumption, often those under cold conditions. However, when building renovation is considered an adaptation strategy, the focus must shift to the contexts where the conditions of vulnerability are most significant. Despite the EU having relatively high adaptive capacity to heat risks, there are significant differences across countries, with the Mediterranean sub-region being particularly vulnerable.

Adaptation is linked to the concept of climate vulnerability—the predisposition to be adversely affected by changes in climate conditions (IPCC, 2022). Vulnerability involves a variety of biophysical and socio-economic factors related to exposure, sensitivity, or susceptibility to impacts, as well as coping and adaptive capacity. Several works have investigated the factors determining urban vulnerability in the Southern EU (Hernández et al., 2018), including vulnerability to heat (VH) (Domene et al., 2022; López-Bueno et al., 2020).

The group of vulnerable people to extreme temperature or heatwave conditions usually includes elderly or young citizens, who suffer from certain physical or mental ailments, or those in precarious socio-economic conditions (De la Osa, 2016). In fact, Eurostat (2024) reports that the elderly population (over 65 years) constitutes 21.3% of the EU's total population and is projected to rise to 32,5 % by 2100. Heat accounted for over 80% of the EU’s average mortality rate from climate-related events between 2010 and 2020 (IPCC, 2022). Furthermore, the energy poverty associated with worsening climatic conditions in summer already affects 30% of the population in the Mediterranean region, with a significant increase expected by mid-century (Bouzarovski, 2014).

In this chapter, we scrutinise VH in the Mediterranean city of Seville and how it relates to the prioritisation of funds for energy renovation of buildings (ERB) from a climate adaptation perspective. Our analysis exposes several challenges that demand future attention in the EU’s Renovation Wave Programme, specifically in the focus area of “Tackling energy poverty and worst-performing buildings” (EC, 2024). We devise potential implementation strategies for addressing these challenges within specific policies and actions, both at the European and local level, with a special focus on public health.

Methodology

Our cross-disciplinary process engaged architects with long-term expertise in the assessment of thermal comfort and geographers focused on climatic risks and housing policies. We applied a mixed-methods approach comprising:

  • Literature review on VH factors and analysis of ERB policies.

  • An expert seminar was held on January 12, 2024 at the University of Seville entitled “Vulnerability to heatwaves and energy renovation in Seville”. The goal was to promote a multidisciplinary dialogue between researchers and professionals from different backgrounds (geographers, environmentalists, architects, health, etc.). Additionally, social and institutional actors directly involved in local and regional policies on residential vulnerability participated in a discussion panel. See the programme in Appendix.

  • A multi-criteria framework integrating social, environmental, and building factors for the assessment of VH at a sub-city district scale. The choice of statistical indicators is based on a literature review as described in Appendix. The indicator set is tested in the case study of Seville, a city with 6 of the 15 poorest urban districts in Spain, where 31.8% of heat-related deaths are caused by climate change.

Challenges and Recommendations for ERB Policies from an Adaptive Approach to Climate Change

Through the multidisciplinary dialogue group during the expert seminar, we were able to examine diverse viewpoints on the impact of escalating heatwaves. In this section, we outline the main reflections we draw from the seminar in the form of key challenges for EU policies.

Climate Change as a Public Health Crisis

One of the most intricate challenges we face in relation to climate change is its recognition as a public health problem (WHO, 2023). This perspective would help prioritise political actions to adapt communities to changes that are already taking place. Historically, warm seasons in the EU had limited health risks. However, this changed with the onset of severe heatwaves at the beginning of the century that now recur annually. In addition, heat protection strategies are more complex than those against cold. It requires passive strategies in buildings to counteract the effects of indoor overheating that are difficult to implement. For this reason, it is imperative to focus on reducing city temperatures and neutralise the added effects of the UHI phenomenon.

During the last decades, the unprecedented intensity of summer heat has significantly increased excess mortality (Ballester et al., 2023). This raises the need for refining forecasting criteria for high-temperature episodes and for redefining the concept of heatwaves itself. Our interdisciplinary dialogue highlighted the importance of consistently redefining heatwaves from both a climatic and health perspective, unifying alert criteria. Moreover, this redefinition should prioritise and assist the most vulnerable populations, establishing tailored emergency protocols and preventive measures.

We define VH as the predisposition of a community to be adversely affected by an extreme heat event, considering its susceptibility and exposure to this event, and the capacity to absorb the effects and adapt to reduce them in the future. Strengthening the management of heatwave risks requires integrating both social and contextual determinants of VH (IPCC, 2022) linked to citizens’ health. For this purpose, it is important to consider and weigh the influence of several aspects:

  • Social, educational, and economic VH factors versus health problems linked to climate change.

  • Difference between deaths due to heat (direct) and deaths due to heat effects (indirect, increased mortality, but linked to previous pathologies), considering that heat stroke represents only 2–3% of mortality and morbidity associated with high temperatures.

  • Inequities as key elements in the framework of social determinants of health (Barton & Grant, 2006), aligned with the definition of VH.

  • Importance of both vulnerability and exposure factors in health risks. Personal factors include age, diseases, treatments, daily habits, jobs, and unemployment. Environmental factors due to socio-economic conditions include poorly insulated housing, difficulties in cooling, urbanised environment, and urban green infrastructure. Additional factors include local climate, early warning systems, and health care services (De la Osa, 2016).

  • Specific protocols in primary health care services for the detection of people who are vulnerable to heatwaves.

Effective Policies Against Energy Poverty

Living in inefficient buildings is often correlated with energy poverty and social problems (EC, 2020). In this regard, a particularly sensitive challenge is how to define the limits and conditions of energy poverty (Croon et al., 2023). As the IPCC's Sixth Assessment Report (IPCC, 2022, 26) recognises: “Inequity and poverty also constrain adaptation, leading to soft limits and resulting in disproportionate exposure and impacts for most vulnerable groups”. The European Commission, in its recommendation of October 2023, also points out:

…addressing the root causes of energy poverty such as the low energy performance of homes and household appliances, high energy expenditure in proportion to household budgets and lower income levels (exacerbated by inflation). The recommendations are accompanied by a Staff Working Document which contains a more detailed analysis of the recommended measures. (EC, 2023b)

The Staff Working Document (EC, 2023c) provides detailed measures addressing the diagnosis, affordability, and underlying causes of energy poverty. We argue for the importance of translating these findings into regulatory measures at both EU and local levels.

Addressing energy poverty effectively requires implementing prescribed measures and allocating available funding where they are most needed. The broad strategy of general ERB programmes with high costs and lacking prioritisation criteria might not be the most effective approach. We urge establishing targeted measures alongside management mechanisms to optimise the allocation of limited funds. In Table 6.1, we contribute to this aim by proposing key indicators in the diagnostic process of VH required for effective ERB planning and implementation. Furthermore, the prevalence of energy poverty in social housing gives public authorities a key role in the optimisation of the ERB process.

Table 6.1 Indicators of residential vulnerability to heat (VH)
Full size table

Finally, we identify several problems concerning the accessibility and distribution of subsidies for ERB to the most vulnerable demographics. Firstly, there are important information deficits and management complexities. Secondly, there is an over-bureaucratisation of the process exacerbated by cultural and digital gaps. Thirdly, there is limited public investment in integrated urban regeneration programmes, which require interdisciplinary teams and socio-educational initiatives. Moreover, the majority of funds are directed towards individual housing, as “the renovation of social and multi-apartment housing faces additional barriers due to the complex decision-making process” (EC, 2020, 22).

Heat Adaptation Actions: Temporal and Spatial Dimensions

Considering the above described problems, another challenge for heat adaptation policies is the prescription of temporal and spatial dimensions. First, a demarcation must be drawn between short- and medium-term measures. Short-term measures, urgent and swiftly implemented, demand proactive administrative actions. These actions include providing immediate, cost-effective solutions for vulnerable households and establishing networks of climatic shelters for extreme temperatures. Communication and awareness campaigns are also crucial. These actions could be promoted through networks of energy consultation points, which are known as “energy coaching” (Schneider et al., 2023), already operational in the Netherlands and the UK, and in some Spanish regions. Improving local and regional qualitative research on perception, awareness, and/or social alertness of heatwaves could also help an efficient enactment of short-term strategies. Medium-term measures include heat adaptation of public spaces and building retrofitting, largely underfunded at the moment. These measures require a pre-diagnostic phase to optimise resource allocation plus post-implementation auditing and evaluation.

Regarding the spatial dimension, defining suitable suburban scales for implementation requires the availability of reliable datasets for a proper diagnosis. The so-called “neighbourhood effect” (Aguado, 2021) is defined as the combination and accumulation of different factors that contribute to VH being aggravated by spatial processes of segregation and degradation. At the same time, the neighbourhood can also be perceived as an opportunity, since local identity and social relations create potential for transformation and resilience (Torres, 2021).

Macro-economic data overshadows escalating poverty rates in EU’s vulnerable neighbourhoods. The EU's Gini coefficient stood at 30.1% in 2022, with the highest income inequality nearing 40%. In numerous EU countries, particularly in the Mediterranean and Eastern sub-regions, inequality is on the rise. Therefore, our recommendation is that ERB should be conceived as a mechanism for redistributing wealth and improving social cohesion. Special attention must be paid to socially vulnerable groups, including homeless and incarcerated individuals, and residents of informal settlements who have limited or no access to water and/or electricity supplies.

Cross-Cutting, Unified, and Comprehensive Databases for an Accurate VH Mapping

The paucity and inadequate quality of accessible data on the multiple factors of VH is a cross-cutting problem to the challenges described above. This deficiency stems from multiple reasons. First, census data is often discontinuous and of limited accuracy, particularly the data on the characteristics of housing construction. Second, there is a conspicuous absence of accurate data on energy consumption. Lastly, the reliability of heat-related mortality data is moderate and faces difficulties in cross-validation of official models. Addressing these problems requires a multifaceted approach by enhancing local catalogues of residential buildings, ensuring the availability of energy consumption at building level and the traceability of data on heat-related health problems.

Even with adequate data, the accurate mapping of VH requires a suitable operationalisation of the VH concept that, as suggested above, considers the intersection of biophysical and socio-economic factors in line with the framework of social determinants of health (Barton & Grant, 2006).

Multi-Criteria Assessment of Vulnerability to Heat

Table 6.1 describes an indicator set to assess the three dimensions of VH proposed by Wolf and McGregor (2013) and Domene et al. (2022): sensitivity, exposure, and adaptability. We propose this multi-criteria framework as a reference for prioritising ERB actions and funds. The choice of statistical indicators, based on a literature review, responds to a triple perspective: socio-economic, environmental, and related to the building characteristics. The integrative SSH-STEM approach within our team led to identifying and precisely adjusting key variables to each VH factor. In addition to these three dimensions, we suggest analysing the boundary conditions that intensify heat effects, such as the UHI phenomenon.

To test the proposed framework, we conducted a statistical multivariate analysis for the case study of Seville, taking the census section of the municipality as the minimum scale. We developed a matrix of 13,598 data, 26 variables for 523 census sections. The research followed an iterative process utilising Principal Component Analysis to reduce data dimensionality. This process influences the final selection of indicators crucial to the studied problem. The determinant of the Correlation Matrix, nearly zero, signifies appropriate data reduction, corroborated by Bartlett's test of sphericity results. The analysis suggests the possibility of creating synthetic indices by combining variables listed in Table 6.1. Depending on application sites, and considering the expressed variables, identifiable components of underlying issues can be obtained as guiding criteria for prioritisation of funds.

Our analysis reveals the following indicators as most prevalent in determining VH in Seville: income level; population over 65 (mostly elderly women living alone); educational level; ageing and quality of buildings; and urban greening. These results are coherent with similar multivariate analysis carried out in other Spanish cities such as Madrid or Barcelona (Domene et al., 2022; López-Bueno et al., 2020). Therefore, we suggest these indicators can be applied to cities with similar characteristics of residential and social VH situations. The present work contributes to identifying key VH factors and the specific variables of each. This methodology could also be used for developing technical databases to support preventive diagnostics in ERB programmes.

Conclusions and Recommendations

Identifying heatwave risks as a public health problem requires adopting a health-oriented approach to climate change policies, including ERB programmes. This means recognising heat as one of the EU's deadliest climate hazards and prioritising heat-related problems and measures, particularly in the Mediterranean region. Moreover, it involves viewing ERB programmes as adaptation strategies focused on the most vulnerable populations, within the framework of social determinants of health.

Given the high costs associated with ERB and the constraints of limited investments, accurate diagnostics are crucial to identifying priority actions and intervention areas. We propose a multi-criteria framework that can be used to prioritise ERB funds. Additionally, we identify a sub-set of indicators that best describe VH in Mediterranean cities: income level; population over 65 (mostly elderly women living alone); educational level; ageing and quality of buildings; and urban greening. To ensure reliable and rigorous results, it is vital to improve the quality and availability of databases concerning health, residential buildings, and energy consumption in dwellings.

Finally, the multidisciplinary dialogue at our expert seminar highlights the obstacles for vulnerable populations in accessing support for climate change adaptation due to information gaps and the complexities of managing overly bureaucratised processes. Addressing these barriers requires raising investment in ERB programmes with a comprehensive approach, interdisciplinary teams, and socio-educational initiatives such as networks of “energy coaching” points.

Altogether, the highlighted challenges and proposals in this chapter emphasise the need for interdisciplinary approaches both in research and implementation of climate change policies to ensure an efficient and just adaptation to increasing heatwave risks.