This chapter analyzes the impact of disasters in Tokyo by evaluating the changes in energy structure and carbon emissions in 2011, 2015, and 2020 through deep analysis of direct and indirect consumption and emissions through input–output tables. Unexpected events can have profound impacts on urban energy supply and consumption systems. It is crucial to assess the impact of such disasters on urban energy use and carbon emissions. The most typical disasters during the past decades are the Great East Japan Earthquake and the COVID-19. Both has significantly influenced urban energy supply and consumption. This research, using Tokyo as an example, quantifies the disaster’s impact on energy use and carbon emissions. The direct energy consumption and the nexus effects with carbon emissions are quantified into 19 categories. Additionally, disaster’s impacts on urban systems are evaluated through comparative analysis. Finally, nexus strategies for energy conservation and emissions reduction are identified. The research will clarify the common and different impacts on energy structures and carbon emissions caused by the Great East Japan Earthquake and COVID-19. The findings will provide scientific evidence for governments making implemental policies for decarbonization and preparing for unprecedented events in future.