Across Australia, extreme heat events are on the rise. In regions with rapid population increase, like Western Sydney and Western Melbourne, this poses a real threat to public health and ecosystem services. In this study, we analysed historic air temperature data from the Australian Bureau of Meteorology, recorded along an east-west gradient across Greater Sydney.

Results showed a significant increase in the number of hot (at or above 35°C) and extreme heat days (at or above 40°C) in the past two decades. We used these records and estimated how many hot and extreme heat days could be expected in coming decades. The results of this analysis are nothing less but alarming: in just 40 years, Western Sydney could experience 160 hot days and 55 extreme heat days. A second analysis that compared air temperature measurements from hundreds of locations in parks, streets, commercial centres and industrial estates in Western Sydney with measurements from nearby BoM data. Here the results revealed that extreme heat is generally underreported, as it occurs more frequently yet is not captured by BoM stations.

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The findings of the study indicate that new heat warning systems are needed to inform local populations about apparent heat risks in their neighbourhoods. However, they also underline the importance of designing and managing urban green spaces to provide maximum cooling while at the same time they need to be capable of enduring more intense and more frequent extreme heat events. Challenges arise in selecting the right plant species when creating new green spaces, and keeping those plants growing in existing green spaces alive. Resilientparks.org is taking up these challenges.

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Watch this space for practical solutions.