Economic value of urban heat mitigation (IRP2-WP6)
This work package has been exploring the UHI mitigation produced from different scales of investment in urban greening, and will quantify the value of this benefit in dollar terms, for example by reduced mortality/morbidity, reduced energy demand and increased productivity. The list of possible areas for benefit-transfer has been fully developed in WP3 and WP4. Increasing levels of investment in green public open space, and associated investments in passive and active irrigation of those spaces, produce increasing benefits in UHI mitigation.
In Tranche 1 CRCWSC research was able to show the clear physical urban cooling benefits of different levels and types of urban greening, but there is currently no credible estimate of the economic value of the cooling produced under different scenarios of WSUD adoption. Therefore there is currently no way to use UHI mitigation in any policy position or business case for greening cities and integrated water management policy changes.
This work package is overcoming this critical barrier in policy knowledge, combining expertise in economic assessment (UWA and RMCG), UHI modelling (Monash University) and urban design response (E2DESIGNLAB). Outputs will be dollar value estimates of the UHI mitigation value produced under different greening and integrated water management settings.
This component of the IRP2 project is lead by Professor Nigel Tapper from Monash University.
In the first phase of this work, the heat mitigation modelling and scenario building approach were developed, and a site was selected in an outer suburb in western Melbourne. The study site was selected based on availability of data and information required to develop the scenarios. The western suburbs of Melbourne tend to be drier and hotter than the eastern suburbs.
An economic literature review on the valuation of the benefits in UHI mitigation has been significantly progressed.
A framework has been developed, including four landscape scenarios involving the derivation of a range of physical variables critical for modelling (e.g. plan area fraction of paved area, buildings, trees, grass, open water bodies, etc.). The four landscape scenarios are defined as:
- No WSUD or whole of water cycle management (WWCM);
- Current regulatory settings for WSUD/WWCM;
- Proposed changes for WSUD/WWCM; and
- A targeted UHI mitigation scenario to achieve a desired cooling (e.g. 2 degrees on extreme heat days).
These four landscape scenarios are to be tested for three summer scenarios to understand the effectiveness of WSUD in different temperatures.
- Cool (~20˚C) summer days
- Average (~26˚C) summer days
- Extreme (~40˚C) summer days
The heat mitigation modelling using the relevant scenarios are currently being undertaken using the SURFEX and CRCWSC's TARGET models.
An economic model is currently being designed to analyse the results of this modelling work to provide dollar value estimates of the UHI mitigation produced under different water sensitive settings.
The existing values that have been identified in the literature will soon be integrated into the non market database being developed under work package 2 (WP2) of this project.