This project involves a strategic programme of activity in a timely new research direction - the 'unintended consequences of decarbonising the built environment'. We aim to transform understanding of this urgent issue that will have enormous impact internationally. In order to predict the possible future states of such a complex socio-technical system, conventional scientific approaches that may have been appropriate for systems capable of being analysed into simple components are no longer applicable. Instead, we need to bring radically new approaches and ways of thinking to bear. We need to develop and extend our multi- and inter- disciplinary ways of working and be informed by modern complexity science.