Cooling Sydney Strategy PLANNING FOR SYDNEY 2050 Above: Sydney CBD (© [Seb Zurcher] / Good Free Photos) Cover & Back: Barangaroo precinct (© [Leonid Andronov] / Adobe Stock) 2 Cooling Sydney Strategy CONTENTS Planning for Sydney 2050 4 General Residential 33 - Recommended Mitigation The Need for Urban Heat Strategies 34 Mitigation Planning 5 - Green Open Space 35 - Cool Facades 36 Urban Overheating Challenges in the City of Sydney 7 Low Density Residential 39 - Climate Conditions in the City of Sydney 7 - Recommended Mitigation Strategies 40 - Increasing Density 8 - Cool Roofs 41 - Surface Temperature Distribution in the City of - Street Trees & Planting 42 Sydney 9 A Resilient Community 45 City of Sydney’s Urban Context 11 - Provision of Heat Refuges 46 - Land Use Zones & Urban - Education Initiatives & Typologies within the City of Campaigns 47 Sydney 12 - Provision of Incentives 48 Urban Overheating Mitigation Strategies 17 Towards a Climate Resilient Sydney 49 - Applicability & Effectiveness of Urban Overheating Mitigation Strategies 18 References 50 Metropolitan Centre 21 Appendix - Land Surface Temperature Map of Greater - Recommended Mitigation Sydney 53 Strategies 22 - Cool & Permeable Pavements 23 - Vertical Greenery 24 - Building Integrated Shading Date: Devices 25 June 2019 Mixed-Use 27 Authors: Lan Ding, UNSW - Recommended Mitigation Baojie He, UNSW Strategies 28 William Craft, UNSW Henry Petersen, UNSW - Water Features & Evaporative Paul Osmond, UNSW Cooling 29 Mattheos Santamouris, UNSW Deo Prasad, CRCLCL - External Shading Structures 30 Carlos Bartesaghi Koc, Deakin University Chris Derksema, CoS - Combination of Strategies 31 Nik Midlam, CoS 3 PLANNING FOR SYDNEY 2050 In 2007, the City of Sydney A key direction of this report and developed a long-term strategic of the planning for Sydney 2050 vision and plan for the future, is to ‘live with our climate’. Within Sustainable Sydney 2030. Building this, extreme heat is identified as on the success of this plan, the the one of the primary challenges City of Sydney are looking beyond for Greater Sydney and addressing the minimum 10-year lifespan it requires collaborative action to develop a vision for ‘Sydney and policy to minimise the 2050’ that is community led and associated health risks and informed by reliable research resource demands. Therefore, the and technical advice. Planning purpose of this report is to provide for Sydney 2050 will look to the urban overheating mitigation recently developed Resilient recommendations to support Sydney report which provides the the strategic planning of Sydney first strategic direction for the city 2050 based on in-depth research to increase its “ability to survive, conducted by the Cooperative adapt and thrive in the face of Research Centre for Low Carbon increasing global uncertainty and Living (CRCLCL) and the University local shocks and stresses” (City of of New South Wales (UNSW). Sydney, 2018). Left: Sydney city skyline facing north (©[ ] / Adobe Stock) 4 Cooling Sydney Strategy THE NEED FOR URBAN HEAT MITIGATION PLANNING The urban heat island (UHI) been developed and refined effect – increased ambient over the last two decades. The temperature in high-density urban correct implementation of these areas compared to surrounding existing mitigation strategies suburban or rural areas (Figure 1) has the potential to decrease – is one of the most documented peak ambient temperatures by areas of climate change. The 2-3°C and can provide significant UHI phenomenon can vary both decreases in cooling energy spatially and temporarily as a demand and heat related mortality function of climate, topography, and morbidity (Santamouris et al., physical form and short-term 2017a). weather conditions (Santamouris et al., 2019). If overlooked in the It is important to note that while planning and designing of our the UHI phenomenon can be cities, it can significantly increase beneficial to cities during winter the demand for energy, water and (e.g. reduced heating costs and healthcare services. cold-related deaths), the negative UHI impacts outweigh these To address the impact of increased benefits in most cities due to their overheating in our cities, mitigation (sub)tropical climates (Roth, 2013). strategies and technologies have Figure 1: Urban heat island temperature profile 5 However, selecting the most effective combination of mitigation An in-depth UHI analysis of the proposed strategies can become challenging Green Square Town Centre redevelopment for local governments, urban to assist the City of Sydney in developing planners and decision-makers mitigation strategies to effectively reduce when faced with varying urban localised and precinct-wide average air development contexts and temperatures (Craft et al., 2019). microclimatic conditions. The suite of urban heat mitigation research conducted by the CRCLCL and An in-depth strategic study investigating UNSW (Figure 2) can provide various mitigation strategies to decrease in-depth insights for the City of ambient temperature in Western Sydney Sydney in developing the most and their impact on cooling and peak effective mitigation strategies for energy demand, thermal comfort and specific urban contexts. heat related mortality (Sydney Water, 2017). The focus of this report is to tailor the research findings specifically to the City of Sydney’s urban context An interactive three-dimensional decision- to support the future planning support tool which enables users to of Sydney 2050. This will ensure visualise and assess urban development that the City of Sydney Local mitigation scenarios for specific urban Government Area (LGA) is able to contexts (CRCLCL, 2019a). survive, adapt and thrive despite the increasing frequency and duration of heatwaves in Sydney. An online, interactive urban heat mitigation index providing high-level guidelines for urban planning decisions to mitigate urban heat in varying climates and development typologies (CRCLCL, 2019b). A design guide for built environment professionals and regulatory agencies seeking to optimise development projects to moderate urban microclimates and mitigate UHI effects in major urban centres across a range of climates in Australia (Osmond & Sharifi, 2017). Figure 2: UHI mitigation research conducted by the CRCLCL and UNSW 6 Cooling Sydney Strategy URBAN OVERHEATING CHALLENGES IN THE CITY OF SYDNEY Climate Conditions in the City of Sydney The overall climate of Sydney is considerably influenced by its coastal position and proximity to the ocean. Despite the positive influence of a cooling sea breeze, coastal cities such as Sydney still suffer from UHI impacts (von Glasow et al., 2013). Areas in Western Sydney experience more frequent extreme heat events than in the City of Sydney LGA due to the absence of these cooling breezes combined with the influence of hot westerly winds, which can result in ambient temperature differences of up to 11°C (Santamouris et al., 2017b) (see appendix). Despite the considerable focus on mitigating urban overheating in Western Sydney, the City of Above: Coastal location Sydney’s temperature in summer of Sydney CBD is continually rising and still (© [jovannig] / Adobe Stock) poses an increased health risk for its inhabitants. Within the City Figure 3 (Left): Projected number of of Sydney LGA, the frequency extreme heat days in of extreme heat days (>35°C) is the City of Sydney (City projected to increase to 15 by 2070 of Sydney, 2016) (Figure 3) (City of Sydney, 2016). 7 Increasing Density Between 2008 and 2018 the local major areas of urban renewal. area population increased by 38.9% in the City of Sydney making As the population and density of it the second fastest growing the City of Sydney increases, the area in NSW (City of Sydney, challenge of urban overheating 2019a). To meet the needs of a is projected to increase (Livada et growing city population, the State al., 2019). The potential benefits of Government has identified areas cooling sea breezes are expected for State Significant Development to weaken with increases of within the City of Sydney LGA dense urban structures (He, 2018). (e.g. Barangaroo, Waterloo/ Therefore, the challenge for the Redfern, Broadway, etc.). The future redevelopment of the City of City of Sydney has also identified Sydney will be to provide increased potential development sites to density through mid and high-rise meet housing demands (e.g. buildings without reducing the Green Square , Harold Park, etc.) city’s ability to mitigate and adapt Below: Barangaroo and together these sites represent to urban heat. redevelopment 8 Cooling Sydney Strategy Surface Temperature Distribution in the City of Sydney Across the City of Sydney LGA, differences in urban fabric (the physical urban environment – built form, scale, density, materials, etc.) and land cover (paved, vegetated, water, etc.) contribute to significant variations in localised temperatures. Figure 4 shows the surface temperature distribution across the City of Sydney LGA at the end of Sydney’s 2018/19 summer and highlights overall surface temperatures can Above: Unshaded concrete and asphalt various hot spots under different be seen in relatively lower-density surfaces in Green urban development conditions urban contexts such as Ultimo Square (see appendix for land surface (2), Green Square (3), Rosebery temperature map of Greater (6) and Alexandria (7) (Figure 4). Sydney). Factors contributing to these higher surface temperatures are Within Sydney’s CBD areas (1), the decreased benefit of cooling