High-Resolution Modeling and Projecting Local Dynamics of Differential Vulnerability to Urban Heat Stress

Abstract
Climate change-induced heat stress has significant effects on human health, and is influenced by a wide variety of factors. Most assessments of future heat-related risks however are based on coarse resolution projections of heat hazards and overlook the contribution of relevant factors other than climate change to the negative impacts on health. Research highlights sociodemographic disparities related to heat stress vulnerability, especially among older adults, women and individuals with low socioeconomic status, leading to higher morbidity and mortality rates. There is thus an urgent need for detailed, local information on demographic characteristics underlying vulnerability with refined spatial resolution. This study aims to address the research gaps by presenting a new population projection exercise at high-resolution based on the Bayesian modeling framework for the case study of Madrid, using demographic data under the scenarios compatible with the Shared Socioeconomic Pathways. We examine the spatial and temporal distribution of population subgroups at the intra-urban level within Madrid. Our findings reveal a concentration of vulnerable populations, as measured by their age, sex and educational attainment level in some of the city's most disadvantaged neighborhoods. These vulnerable clusters are projected to widen in the future unless a sustainable trajectory is realized, driving vulnerability dynamics toward a more uniform and resilient change. These results can guide local adaptation efforts and support climate justice initiatives to protect vulnerable communities in urban environments. Key Points - Population projections by age, sex and education at small-area levels allow for high-resolution heat vulnerability modeling - Vulnerability to heat stress can vary widely between different areas in a city, and even within a single neighborhood - Areas that are vulnerable today are projected to become even more vulnerable in all Shared Socioeconomic Pathway scenarios except for that assuming a sustainable development narrative Plain Language Summary Heat stress is a major risk factor for human health, especially in cities where more people are exposed to increasingly higher temperatures in summer. Cities are usually hotter than their surrounding rural areas due to the predominance of dark, impervious surfaces which absorb more heat. Assessing heat risks for public health requires measurements of the hazard, such as a prolonged period with high temperatures, the population exposed to the hazard and characteristics of populations that make them more vulnerable to heat related diseases or even death. Various approaches and tools for risk assessment have been developed, but most of them focus on the hazard and exposure components. In this paper, we measure and project vulnerability to heat stress in alternative scenarios, using different population characteristics, such as age, sex and education. Our results show that there are compelling differences between areas within the city of Madrid and that areas that are vulnerable today will become even more vulnerable unless we follow a path of sustainable development. Detailed assessments of the spatial distribution of vulnerability within a city are relevant for developing adaptation solutions that target vulnerable populations and are thus more effective in reducing heat-related risks.
Description
This article was originally published in Earth's Future. The version of record is available at: https://doi.org/10.1029/2024EF004431. © 2024. The Author(s). This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Keywords
heat stress, vulnerability, climate risk, cities, climate adaptation, sustainable cities and communities, climate action
Citation
Marginean, I., Crespo Cuaresma, J., Hoffmann, R., Muttarak, R., Gao, J., & Daloz, A. S. (2024). High-resolution modeling and projecting local dynamics of differential vulnerability to urban heat stress. Earth's Future, 12, e2024EF004431. https://doi.org/10.1029/2024EF004431