Urban heat mitigation in Sydney, Australia : tree effects and policy context

Abstract

Rapid urbanization, land use modification and anthropogenic heat emission have accelerated the Urban Heat Island Effect (UHIE) in cities. The UHIE can be defined as the "discernible temperature difference between urban and adjacent rural areas caused by the excess heat emitted and the solar gain trapped by the urbanised environment" (Gartland, 2008). Trees provide cooling through evapotranspiration and surface shading. This thesis takes a transdisciplinary approach to assess the efficacy of trees in cooling urban spaces in Sydney and how well this function is embedded in government policies. Overall, this research showed that both science and policy play a key role in the pathway to achieve urban cooling. Effective urban heat management must be guided by comprehensive urban planning policies. Therefore, the key planning policies of local and state government agencies should contain a standalone provision for urban heat management. While there are numerous scientific studies conducted in Australia on UHIE, their integration within strategic planning at local and state government levels is currently inadequate. Surprisingly, none of the councils examined in the study had firm canopy cover targets associated with expected cooling benefits. This indicates that policy makers at all government levels need to have a deeper understanding about urban heat and how to reduce it or adapt to it. This research provides new strategic guidance to better understand spatial and temporal variability of urban heat and offers improvements to existing practices for planting and managing urban trees.

Date of Award	2021
Original language	English