Investigating the Relationship between Human Activity and the Urban Heat Island Effect in Melbourne and Four Other International Cities Impacted by COVID-19

Abstract

Climate change is one of the biggest challenges of our times, even before the onset of the Coronavirus (COVID-19) pandemic. One of the main contributors to climate change is greenhouse gas (GHG) emissions, which are mostly caused by human activities such as the burning of fossil fuels. As the lockdown due to the pandemic has minimised human activity in major cities, GHG emissions have been reduced. This, in turn, is expected to lead to a reduction in the urban heat island (UHI) effect in the cities. The aim of this paper is to understand the relationship between human activity and the UHI intensity and to provide recommendations towards developing a sustainable approach to minimise the UHI effect and improve urban resilience. In this study, historical records of the monthly mean of daily maximum surface air temperatures collected from official weather stations in Melbourne, New York City, Tokyo, Dublin, and Oslo were used to estimate the UHI intensity in these cities. The results showed that factors such as global climate and geographic features could dominate the overall temperature. However, a direct relationship between COVID-19 lockdown timelines and the UHI intensity was observed, which suggests that a reduction in human activity can diminish the UHI intensity. As lockdowns due to COVID-19 are only temporary events, this study also provides recommendations to urban planners towards long-term measures to mitigate the UHI effect, which can be implemented when human activity returns to normal.

Impact of COVID-19 Lockdown on Vegetation Indices and Heat Island Effect: A Remote Sensing Study of Dhaka City, Bangladesh

“…However, this study fulfills the limitations and recommendations of some other studies. For example, Wai et al, (2022) recommended that investigating the ongoing pandemic situation by specifically observing the LST variation from a satellite image analysis between the years 2020 and 2021 would provide a better representation on the effects of human movement restrictions towards the UHI intensity [28]. Lastly, there are numerous different methods for assessing heat island zones and mapping heat island intensity.…”

“…The principal causes of the UHI [23][24][25][26] include the alteration of surface form, surface structure, fabric, and property changes that are linked with urbanization and the subsequent change in climate. Nevertheless, UHI is also influenced by human activities that emit anthropogenic heat (AHR) [27,28].…”

“…Guha and Govil [45], for example, analyzed the impact of the COVID-19 lockdown on the LST and the NDVI in 2021. Wai et al, (2022) examined the association between human activity and the UHI effect on five international cities that were impacted by COVID-19 [28]. Ibrahim et al, (2021) performed another study by applying machine-learning models to determine the effect of COVID-19 shutdown on aerosol optical depth over Europe [46].…”

Did the Covid-19 restrictions influence land surface temperatures in Southeast Asia? A study from Ho Chi Minh City, Vietnam

“…During the pre-pandemic conditions, UHI phenomena in major cities in the world have been observed to be increasing annually, particularly in the winter (Manoli et al 2019 ). The Covid-19 pandemic period, when majority of the cities were under strict lockdown and/or extremely reduced human activities, was a unique condition to investigate the influence of anthropogenic activities on LST (and hence UHI phenomenon) (Wai et al 2022 ). A number of studies reported a reduction in LST (and hence UHI effect) during the pandemic period (e.g.…”

“…A number of studies reported a reduction in LST (and hence UHI effect) during the pandemic period (e.g. El Kenawy et al 2021 ; Jallu et al 2022 ; Liu et al 2022 ; Saputra et al 2022 ; Wai et al 2022 ). The key reason for variations in UHI during the lockdown period was reported as the reduction in greenhouse gas emissions (El Kenawy et al 2021 ).…”