A rapid assessment method and policy framework for improving heatwave resilience in Tasmania’s major cities

Heatwaves kill more Australians than all other natural hazards. While Tasmania experiences fewer heatwave-related deaths than other Australian states, climate change projections indicate that Tasmanian cities will experience more days of extreme heat in the decades ahead. The structure of Tasmania’s population, with a higher proportion of adults over 65 years of age, and a higher proportion of the population experiencing chronic health issues and/or a disability, means that many Tasmanians will be vulnerable to heat-related disease and death in the future.

Acting now to address extreme heat in Tasmania’s settlements can save lives, reduce the burden of disease on individuals and the healthcare system, and increase the liveability of the state’s towns and cities. To inform effective policy and planning it is important to know which parts of the built environment have higher heat loading and where people live who experience comparative marginality and disadvantage, making them more vulnerable to heat. This report addresses those tasks, presenting findings of research that has developed and tested a rapid assessment tool for understanding the potential impacts of extreme heat events in Tasmanian cities.

Using a combination of remote sensing (satellite imagery analysis) and site audits, land surface temperatures were mapped for the City of Launceston, Tasmania. The composition of the population potentially vulnerable to heat was also mapped. And using machine-learning techniques, the tree canopy of Launceston was characterized and mapped for the city. Statistical analyses were undertaken to assess associations between land surface temperature, tree canopy distribution, and population characteristics. Findings show that parts of Launceston are comparatively hotter, have less tree canopy cover and have a higher proportion of residents who may experience heat vulnerability. It is likely that similar patterns occur in Hobart, Devonport, and Burnie.

There are a range of steps that can be taken to reduce heat vulnerability. These include tree planting and urban greening, adaptive retrofits of residential dwellings for thermal efficiency, energy efficiency and thermal efficiency standards for new buildings, education, and implementing a targeted warning system for households with higher levels of risk of mortality and morbidity during extreme heat events. Many of these actions will cross jurisdictions and span governance – from the local to the state scale. Effective responses will require a whole of government approach. Acting now can avoid future costs and presents a no-regrets approach to managing heatwave risks in Tasmania.