The coronavirus disease 2019 (COVID-19) pandemic of 2020 drastically changed urban lifestyles. Workers were forced to minimize commuting to their workplaces, older adults were banned from using meeting facilities, and children were prohibited from going to school. The consequent lack of exercise, accumulated stress, and reduced well-being are likely to have become problems, which may be improved by using urban green spaces (UGS). This study clarified the characteristics of users of UGS in Tokyo during the COVID-19 pandemic, focusing on telecommuters, older adults, and families with children. An online questionnaire survey was conducted among Tokyo residents, and 3085 responses were obtained. A binomial logistic regression analysis was conducted with the use and evaluation of UGS as the objective variables. The results showed that older adults and families with children who had been using UGS before the pandemic and telecommuters who newly started using UGS during the pandemic used UGS differently. Older adults and families with children tended to use small parks and appreciated human connections. Telecommuters often used greenways, temples, and shrines, valuing stress-reducing functions. Given that a changing lifestyle brings new UGS users new preferences, urban planners should consider that UGS require change with the time.

Designing waterfront redevelopment generally focuses on attractiveness, leisure, and beauty, resulting in various types of building and block shapes with limited considerations on environmental aspects. However, increasing climate change impacts necessitate these buildings to be sustainable, resilient, and zero CO₂ emissions. By producing five scenarios (plus existing buildings) with constant floor areas, we investigated how buildings and district forms with building integrated photovoltaics (BIPV) affect energy consumption and production, self-sufficiency, CO₂ emission, and energy costs in the context of waterfront redevelopment in Tokyo. From estimated hourly electricity demands of the buildings, techno-economic analyses were conducted for rooftop PV systems for 2018 and 2030 with declining costs of rooftop PV systems. We found that environmental building designs with rooftop PV system are increasingly economical in Tokyo with CO₂ emission reduction of 2–9% that depends on rooftop sizes. Payback periods drop from 14 years in 2018 to 6 years in 2030. Toward net-zero CO₂ emissions by 2050, immediate actions are necessary to install rooftop PVs on existing and new buildings with energy efficiency improvements by construction industry and building owners. To facilitate such actions, national and local governments need to adopt appropriate policies.