In this paper, we employ a unified framework of sustainability assessment by capital stocks to review Professor Kazuhiro Ueta’s work and relevant fields. Socio-metallic study, proposed around 1980, focused on the disconnect between the use and disuse of metal stocks, and was aimed at their reconnection. This concept spawned three relevant fields in modern environmental economics: industrial ecology, economics of waste and recycling, and theory of sustainable development. Also, attempts were made to integrate socio-metallic study and economics, by accounting for material flow and material balance in economic models. More recently, an aggregate index of various capital assets―inclusive wealth―is increasingly used as an indicator of sustainable development; we also review its promises and pitfalls.

This paper reviews the argument over the concept of "critical natural capital" (hereafter, CNC), which was proposed to focus on the non-substitutability of natural capital. It attempts to clarify the issues and challenges of putting the CNC concept into operation. Specifically, I examined the framework that was developed in Ekins et al. (2003) to specify CNC by physical conditions such as non-substitutability, irreversibility, immoderate loss, etc. These conditions have been thought of as appropriate by other authors, however, I argue that one can specify CNC at will using the framework of Ekins et al. (2003) since those conditions are not strictly defined. Incorporating other relevant issues such as technological development or discount factor into the framework of CNC, we need to refine the CNC conditions further.

Environmental management systems (EMS) have been applied by various kinds of organizations and have spread worldwide. This paper focuses on the EMS as a tool for realizing sustainable 'machizukuri' (community development) based on the theory of sustainability. Observing that ISO14001:2015 revisions include the theory of sustainability, EMS implementations by local governments, enterprises and residents are discussed in terms of the principle of local autonomy. From the above, we indicate a future research direction for sustainable community development.