The role of carparks as urban heat islets in western Sydney

Abstract

This research has shown that carparking space in western Sydney is expanding synchronously with population growth. As a result of high car dependency in the region, provision of this space seems unavoidable. The present work has also shown how effective tree shade can be to cool down carpark surfaces and improve human thermal comfort. This knowledge must be used by urban planners, landscape architects and developers when designing new infrastructure for the region, which already experiences extreme heat every summer. The largely unshaded space of several square kilometres of black asphalt is likely to contribute to this heat. The region is experiencing rapid urbanisation and densification. This study demonstrated a positive relationship between the growth of local populations and the area used by carparks. Hence, continued population growth will lead to more carparks, which in turn will contribute to more summer heat. This vicious cycle and its predictable effect must be broken. The comparison of carpark space and its green cover in 2010 and 2019 has shown that no improvements in designing and building heat-smart carparks have been made in the past decade. Many strategies to prevent carparks from becoming heat islets are available, including trees to provide shade, cool pavements, reflective surface sealants or solar panels. None of these strategies have been found at noteworthy scale in the 2250 carparks studied here. More research on the impacts of carparks on microclimates and the effectiveness of different heat mitigation strategies is necessary. Currently this research is absent in western Sydney where local populations are growing fast, transforming the region from rural and peri-urban into metropolitan space. Large tracts of pervious land covered by vegetation has been and will be turned into impervious hard space. This transformation is affecting the climate of the entire region and thus requires concerted efforts to mitigate the negative effects of increasing heat. This is especially urgent as climate change is already resulting in more frequent and longer lasting heatwaves with hotter peak temperatures. Responsible urban design must address this issue to provide liveable environments.

Date of Award	2020
Original language	English