To realize a sustainable decarbonized society by 2050 amidst the adverse consequences of a declining and aging population, visions and policies must be designed to consider the perspectives of future generations. This study presents a framework that envisions a sustainable decarbonized society in 2050 by introducing a back casting approach to policy formulation. This study analyzes the “Future Chart 2050,” a framework that simulates and numerically visualizes the future status of society across various sectors, including economic, social, environmental, and physical infrastructure. In this framework, policy changes in the current trend can change the future status indicated in the future chart. Based on the “Future Chart 2050,” future workshops involving junior and senior high school students and young local government officials were conducted in various cities. Using the back casting policy approach, participants were given questionnaires to measure the effectiveness of their perspectives. This study reports on the policy measures proposed by the participants in future workshops. The findings revealed that the participants showed a strong interest in local issues, expressing a desire to contribute to the community, and feeling that they could collaborate with various individuals. They also showed enthusiasm for assuming future leadership roles and implementing activities aimed at improving local governance and addressing the problems of the host city. The recommendations realized from the workshop can be used for policies that anticipate the future of local governments, considering factors such as population, aging, industry, medical care, nursing care, and childcare, and can therefore support local governments in acting to achieve a sustainable decarbonized society by 2050.