The world's cities are responsible for some three-quarters of global energy use and energy-and industry-related greenhouse gas emissions. Global climate change mitigation, and ecological sustainability in general therefore crucially depend on the sustainability practices of urban residents. Present climate change policies are not working, as annual emissions are still growing. Clearly, new approaches are needed. One possible new approach is to implement smart city policies. In this paper, the potential for smart city policies to help make significant energy (and related greenhouse gas) savings in urban transport and building construction and operation is investigated. The main findings are that although significant potential exists, it will not be realised unless supporting policies are in place. Furthermore, support for smart city innovation will be weakened unless the challenges of data privacy, security and reliability can be overcome.

© 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC-BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).