Mortality Associated with High Ambient Temperatures, Heatwaves, and the Urban Heat Island in Athens, Greece

John Paravantis,Mat Santamouris,Nikoletta Kontoulis,Chrysanthi Efthymiou,Constantinos Cartalis

doi:10.3390/su9040606

Abstract

Abstract: Climate change looms as the biggest threat of the 21st century, and its effect on urban mortality is exacerbated by urban heat islands. This study analyzes the impact of high temperatures, heatwaves, and the urban heat island on the cardiovascular and respiratory mortality of people over 65 years of age for the years 2002 to 2012. The area of application is Athens, Greece, an urban agglomeration experiencing an urban heat island of high intensity. The correlation of the daily cardiovascular and respiratory mortality count of people over 65 years of age with various temperature measures confirmed a U-shaped exposure response curve, with fewer deaths in the range of moderate temperatures. At high and very high temperatures, this mortality increased by 20 to 35% correspondingly, at a 99.9% significance level. Mortality was further investigated with ordinary least squares, Poisson, and negative binomial times series models, which, although suffering from poor fit, showed a one-day lag for the maximum temperature effect on mortality. Finally, cluster analysis for observations confined to May to September, confirmed by multiple discriminant analysis, showed the existence of six clusters, with the highest excess mortality count of 23% for the cluster that included the hottest days and 20.6% for the heatwave cluster. To this end, it is recommended that policies target high ambient temperatures and heatwaves as a priority.

Highlights

Climate change may well constitute the biggest global health threat of the 21st century [1,2]
The negative impact of global warming is exacerbated by the urban heat island (UHI) phenomenon, which refers to cities being hotter than surrounding rural areas, affecting people in urban areas in ways worse than mild thermal discomfort [3]
The UHI and the local climate change affect the environmental quality of cities highly as they increase the energy spent for cooling purposes [6], increase the peak electricity demand during the summer period [7], deteriorate thermal comfort conditions [8], and increase the thermal stress to low income and vulnerable segments of the population [9]

Summary

Introduction

Climate change may well constitute the biggest global health threat of the 21st century [1,2]. The negative impact of global warming is exacerbated by the urban heat island (UHI) phenomenon, which refers to cities being hotter than surrounding rural areas, affecting people in urban areas in ways worse than mild thermal discomfort [3]. Higher urban ambient temperatures are the result of the positive urban thermal balance that is highly controlled by the increased absorption of shortwave radiation and the excessive release of anthropogenic heat. Given the impact of increased urbanization on the intensity of the urban heat island and that heatwaves are projected to become more frequent due to climate change, heat-related health risks for urban residents are expected to worsen in the twenty-first century. Adaptation and mitigation strategies will require, among others, more reflective materials and more green and blue spaces

Objectives

Methods

Results