Mortality Burden of Heatwaves in Sydney, Australia Is Exacerbated by the Urban Heat Island and Climate Change: Can Tree Cover Help Mitigate the Health Impacts?
Timothy B. Chaston,
Richard A. Broome,
Nathan Cooper,
Gerard Duck,
Christy Geromboux,
Yuming Guo,
Fei Ji,
Sarah Perkins-Kirkpatrick,
Ying Zhang,
Gnanadarsha S. Dissanayake,
Geoffrey G. Morgan,
Ivan C. Hanigan
Affiliations
Timothy B. Chaston
University Centre for Rural Health, The University of Sydney, Lismore, NSW 2480, Australia
Richard A. Broome
Centre for Air Pollution, Energy and Health Research (CAR), Sydney, NSW 2037, Australia
Nathan Cooper
Centre for Air Pollution, Energy and Health Research (CAR), Sydney, NSW 2037, Australia
Gerard Duck
Strategic Analysis and Investment Unit, Strategic Reform and Planning Branch, NSW Ministry of Health, Sydney, NSW 2037, Australia
Christy Geromboux
University Centre for Rural Health, The University of Sydney, Lismore, NSW 2480, Australia
Yuming Guo
Centre for Air Pollution, Energy and Health Research (CAR), Sydney, NSW 2037, Australia
Fei Ji
Science, Economics and Insights Division, Department of Planning and Environment, Sydney, NSW 2150, Australia
Sarah Perkins-Kirkpatrick
School of Science, University of New South Wales, Canberra, ACT 2890, Australia
Ying Zhang
Sydney School of Public Health, The University of Sydney, Sydney, NSW 2050, Australia
Gnanadarsha S. Dissanayake
Strategic Analysis and Investment Unit, Strategic Reform and Planning Branch, NSW Ministry of Health, Sydney, NSW 2037, Australia
Geoffrey G. Morgan
University Centre for Rural Health, The University of Sydney, Lismore, NSW 2480, Australia
Ivan C. Hanigan
University Centre for Rural Health, The University of Sydney, Lismore, NSW 2480, Australia
Heatwaves are associated with increased mortality and are exacerbated by the urban heat island (UHI) effect. Thus, to inform climate change mitigation and adaptation, we quantified the mortality burden of historical heatwave days in Sydney, Australia, assessed the contribution of the UHI effect and used climate change projection data to estimate future health impacts. We also assessed the potential for tree cover to mitigate against the UHI effect. Mortality (2006–2018) records were linked with census population data, weather observations (1997–2016) and climate change projections to 2100. Heatwave-attributable excess deaths were calculated based on risk estimates from a published heatwave study of Sydney. High resolution satellite observations of UHI air temperature excesses and green cover were used to determine associated effects on heat-related mortality. These data show that >90% of heatwave days would not breach heatwave thresholds in Sydney if there were no UHI effect and that numbers of heatwave days could increase fourfold under the most extreme climate change scenario. We found that tree canopy reduces urban heat, and that widespread tree planting could offset the increases in heat-attributable deaths as climate warming progresses.
