Addressing the Urban Heat Islands Effect: A Cross-Country Assessment of the Role of Green Infrastructure

Abstract

The Urban Heat Islands (UHI) effect is a microclimatic phenomenon that especially affects urban areas. It is associated with significant temperature increases in the local microclimate, and may amplify heat waves. Due to their intensity, UHI causes not only thermal discomfort, but also reductions in the levels of life quality. This paper reviews the important role of green infrastructure as a means through which the intensity of UHI may be reduced, along with their negative impact on human comfort and wellbeing. Apart from a comprehensive review of the available literature, the paper reports on an analysis of case studies in a set of 14 cities in 13 countries representing various geographical regions and climate zones. The results obtained suggest that whereas UHI is a common phenomenon, green infrastructure in urban areas may under some conditions ameliorate their impacts. In addition, the study revealed that the scope and impacts of UHI are not uniform: depending on peculiarities of urban morphologies, they pose different challenges linked to the microclimate peculiar to each city. The implications of this paper are threefold. Firstly, it reiterates the complex interrelations of UHIs, heat waves and climate change. Secondly, it outlines the fact that keeping and increasing urban green resources leads to additional various benefits that may directly or indirectly reduce the impacts of UHI. Finally, the paper reiterates the need for city planners to pay more attention to possible UHI effects when initiating new building projects or when adjusting current ones.

Unrelented heat: international trends and impacts on human health in 15 selected cities

“…A recent study (Leal Filho et al 2021) has shown that, due to their intensity, excessive urban heat causes not only thermal discomfort, but also reductions in the levels of life quality; and this still remains as an invisible risk in many cities (Brimicombe et al 2021) Based on the need to shed some light on the various factors that characterize urban heat, the aim of this communication is to address the impacts of urban heat on human health, presents an international study identifying current trends, and suggesting some measures to address the problem.…”

Appraising Agroecological Urbanism: A Vision for the Future of Sustainable Cities

“…Although urbanization provides many social and economic opportunities, it is regarded as one of the most pressing global challenges of the 21st century, with more than 60% of the world's population expected to live in cities by 2030, including approximately 55% and 20% of the world's poor and undernourished, respectively [29]. Furthermore, the effects of UHI have been reported to pose a significant threat to the world's growing urban societies, affecting energy consumption and increasing emissions of GHGs and air pollutants [30,31]. According to Zhu et al [32], urban areas consume roughly two-thirds of the world's energy and emit approximately 80% of GHGs, particularly CO 2 .…”

A Comprehensive Review of Different Types of Green Infrastructure to Mitigate Urban Heat Islands: Progress, Functions, and Benefits

“…Rapid urbanization has caused land-use change, replacing green spaces and vacant land with urban infrastructures, and climate change has increased the frequency of extreme climatic events and the intensity of heatwaves, which has strongly impacted the urban thermal environment, resulting in higher land surface temperatures and higher thermal absorption of solar radiation [1][2][3]. This phenomenon leads to what is known as the urban heat island (UHI), whereby urban areas have higher temperatures than surrounding non-urban areas [4]. UHIs affect human health and human thermal comfort, intensifying the peak temperature during the day and night in high-density urban areas [5][6][7].…”