Our winter special issue features contributions on circular cities, highlighting the importance of urban centers in promoting cross-sector coordination and regenerative innovation in food, energy, construction, and waste
This article illuminates the drivers of exponential improvements in performance and cost and explains why some technologies experience more rapid improvements than others. It shows how exponential improvements in performance and cost are largely driven by two mechanisms: creating materials to better exploit their physical phenomena; and geometric scaling. Improvements in some technologies are directly experienced through these two mechanisms, while improvements in higher-level "systems" are indirectly experienced through improvements in specific "components." Understanding these drivers can help us better recognize when new technologies might become economically feasible and thus create appropriate policies for promoting improvements.