Evaluation of long-term urban transitions in a megacity’s building sector based on alternative socioeconomic pathways

A Future Outlook of Narratives for the Built Environment in Japan

“…This allows for local and sectoral interpretations and to enable developing nested storylines and quantifications [24]. Hence, while the SSPs were originally developed and applied at the global level [16], they have been extended to the regions, countries [17], cities [18,20], and sectors [19] including the buildings sector [8,10,25].…”

“…In a second step, we have mapped evolutions across all SSPs to these aspects defined above. We grounded our inputs on previous works [10,18], statistics for Japan, existing literature on urban and building theory, scenario and trends that have been referred in this paper and the previous works, and expert knowledge. A third step consolidated these individual elements into consistent narratives to describe a coherent story for each scenario.…”

“…These SSPs specifically target the narratives of the built environment, therefore, the approach of scale-based investigation (National, City, Neighborhood, and Buildings) is used to downscale the macro observations to the human scale. For analyzing the built environment, urban form factors and human settlements (urban-rural migration and buildings) are the key elements that were previously analyzed for Japan in the city scale Tokyo SSPs [10,18]. Urban-rural migration and lifestyle factors are also key factors to achieve the balanced sustainable society in Japan.…”

“…In the actual situation, some tendencies can be seen, such as the shift from an SSP1 Growth-dependent, centralized service society to a more nature-based, decentralized SSP1 Beyond-growth society. This might occur earlier than it is assumed because Japanese infrastructures are close to the period in which they need to be reconstructed or renovated [10]. Therefore, although these crises are a huge threat to society, people could create innovative recovery strategies with the increase of urgent necessity and growing political will.…”

“…However, modern developments, specifically after the industrial revolutions, significantly changed the built environment and lifestyles. Recent overall construction decision making and lifecycles are hugely influenced by the economic growth trend [10]. Large cities increased the populations and work forces that expanded the inequalities between cities as well as urban and rural.…”