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

Cheuk Yin Wai,Raphael Chukwuka Nnachi,Prudvireddy Paresi,Anne W M Ng,Muhammad Atiq Ur Rehman Tariq,Nitin Muttil

doi:10.3390/su14010378

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.

Highlights

Introduction iationsFollowing the declaration of a global pandemic by the World Health Organization (WHO) on 11 March 2020, many countries had to tighten their borders and apply lockdown measures to limit the spread of COVID-19 and reduce the deaths [1,2]
The Australian Energy Market Operator (AEMO) reported that the energy demand in Victoria reduced by 8% during morning peak
The Australian Energy Market Operator (AEMO) reported that the energy demand in Victoria reduced by 8% during morning peak time in April 2020 [7]

Summary

Introduction

Following the declaration of a global pandemic by the World Health Organization (WHO) on 11 March 2020, many countries had to tighten their borders and apply lockdown measures to limit the spread of COVID-19 and reduce the deaths [1,2]. By November 2020, there had been 5.3 million confirmed cases and 1,305,164 deaths recorded globally [3]. Governments around the world were struggling to stop the spread of the virus and began to introduce strict policies that limited human contacts and activities to prevent further transmission of the virus [4]. The Australian Energy Market Operator (AEMO) reported that the energy demand in Victoria reduced by 8% (approximately 400 Megawatts) during morning peak

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