Eco Investor March 2014


Urban Design and Heat Waves

Insulation, passive solar building design, heat reducing urban planning, and air conditioners for high-risk groups are likely to reduce deaths during heatwaves. In Australia heatwaves have a greater negative impact on population health than any other natural hazard, says a report by Monash University and the National Climate Change Adaption Research Facility.

Heat-related illness and death will increase as climate change progresses, with the most vulnerable groups being older people, young children, people with chronic disease and those living in built-up areas in cities. There will also be greater demand for emergency services such as ambulances during hot weather, and emergency service heatwave planning.

The report, A Spatial Vulnerability Analysis of Urban Populations During Extreme Heat Events in Australian Capital Cities, says communities can act to reduce heat exposures during periods of extreme summer temperatures.

This can be done by changing their behavior and living environments, understanding the nature and location of high-risk areas, and through heatwave adaptation planning.

The study developed a tool to map population vulnerability to extreme heat events in large urban areas. This identified the daily temperatures at which excess heat-related illnesses and deaths occurred and mapped areas in the cities where these events occurred. The local environment, the health status of a population and the demographic structure of a population all contribute to vulnerability. All three aspects were included in the index of vulnerability.

The index was used to create a vulnerability map for each capital city through a visual representation of risk during extreme heat events.

The report says "Areas of high urban density require careful planning to offset the urban heat island effect which intensifies heat exposures during hot weather in built-up areas." High risk groups such as the elderly may also need some modification to their local environment such as shading from vegetation or access to cool places.

Of interest to investors is that the report says green space, urban design and housing can assist to reduce heat-related health issues.

Scientific studies have shown that urban green space reduces the risk of heat-related mortality and illness. For example, a study of heat stroke during the 1980 heatwave in St Louis and Kansas City found an inverse relationship between the risk of non-fatal heat stroke and the extent of tree and shrubbery growth around residences. An increased area of urban green spaces in Shanghai was said to be an important factor in reducing the health impact of heatwaves from 1998 to 2003.

Urban vegetation can reduce temperatures in urban areas by providing shade, evaporative cooling through evapotranspiration, and reduced heat storage capacity compared to bricks and other building materials.

Older residential buildings can make it harder to manage indoor thermal conditions and energy demand, since they are more likely to be poorly insulated.

The location of buildings can influence the intensity and duration of exposure to increased temperature, with city dwellers at higher risk than those living in non-urban areas.








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