What we know and do not know about New Zealand's urban microclimate: A critical review

Despite the remarkable contribution of urbanisation to socio-economic development, it has complicated negative impacts on the environment. The growth of urbanisation has noticeable adverse impacts on urban microclimate and parameters generating the urban heat island (UHI) effect. These impacts, exacerbated by the gradual influences of global warming over time, make urban microclimate changes more complex. The future urban development and climate change adaptation plans in New Zealand (NZ) show almost no evidence of considering the status of future urban microclimate, UHI and outdoor thermal comfort. An initial literature review showed a relatively small number of papers and grey literature on urban microclimate in NZ. This motivated the authors to explore the status of studies on the urban microclimate and the following impacts on UHI and outdoor thermal comfort in NZ. The results showed a relatively small body of knowledge on urban microclimate studies in research articles published and governmental reports in the context of NZ. Likewise, the inconsistency of research parameters and methods studied and the lack of validation in the available studies, plus the neglection of future urban development and urban morphology, limit the clarity of the scientific understanding of changes to the urban microclimate in NZ. The results of this study address the missing links and provide new insight for future studies. This study suggests providing models that consider the continuous changes to the urban microclimate considering the uncertainty of climate change impacts on weather factors such as temperature and airflow. Assessment of the impact of current and future urban morphology on UHI is necessary to develop optimised urban design guidance.