The impact of climate change and urban growth on urban climate and heat stress in a subtropical city. (10th February 2019)

• Record Type: Journal Article
• Authors: Chapman, Sarah; Thatcher, Marcus; Salazar, Alvaro; Watson, James E.M.; McAlpine, Clive A.
• Is Part Of: International journal of climatology. Volume 39:Number 6(2019)
• Page Start: 3013
• Page End: 3030
• Publication Date: 2019-02-10
• Subjects: climate change -- heat stress -- subtropical -- urban heat island; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.5998
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract : Urban residents face increasing risk of heat stress due to the combined impact of climate change and intensification of the urban heat island (UHI) associated with urban growth. Considering the combined effect of urban growth and climate change is vital to understanding how temperatures in urban areas will change in the future. This study investigated the impact of urban growth and climate change on the UHI and heat stress in a subtropical city (Brisbane, Australia) in the present day (1991–2000) and medium term (2041–2050; RCP8.5) during summer. A control and urban growth scenario was used to compare the temperature increase from climate change alone with the temperature increase from climate change and urban growth. Average and minimum temperatures increased more with climate change and urban growth combined than with climate change alone, indicating that if urban growth is ignored, future urban temperatures could be underestimated. Under climate change alone, rural temperatures increased more than urban temperatures, decreasing the effect of the UHI by 0.4 °C at night and increasing the urban cool island by 0.8 °C during the day. With climate change, the number of hot days and nights doubled in urban and rural areas in 2041–2050 as compared to 1991–2000. The number of hot nights was higher in urban areas and with urban growth. Dangerous heat stress, defined as apparent temperature above 40 °C, increased with climate change and occurred on average 1–2 days every summer during 2041–2050, even in shaded conditions. There was higher temperature increases with urban growth and climate change than with climate change alone, indicating that reducing the effect of the UHI is vital to ensuring urban growth does not increase the heat stress risks that urban residents will face in the future. Abstract : Climate change increased temperatures in urban and rural areas; however, rural temperatures increased by more than urban temperatures. Urbanization primarily increased night‐time temperatures in the city; however, nearby rural areas were also affected by urbanization and were warmer and drier than when urbanization was excluded. Heat stress increased at all locations, and dangerous heat stress occurred even in shady conditions.