This paper reviews the ideas of measuring physical and economic sustainability of human civilisation proposed by different schools of thought, namely earth sciences, ecological economics, neoclassical economics and engineering, in order to fill the cognitive gaps between the different disciplines. The paper focuses on physical material and energy flows that enable human economic activities and introduces the distinction between flow and stock, as well as that between material and energy.
It proposes a revised operational principle of sustainability, or transition towards new state of civilisation: The overall vision of a civilisation based on natural flow and man-made stock, using natural energy stock during the transition phase, supplemented by the following amended operational principle: (a) Ecological services that are needed to maintain life shall be conserved, and waste and pollution levels shall be within the natural assimilative capacity; (b) consumption shall be within the capacity of renewable resources; and (c) consumption of non-renewable resources shall be associated with investment in renewable substitutes.
The paper also provides selected indicators, following the revised operational principle: (a) Degree of dependence on natural hydrocarbon stock regarding fuel consumption for heating, transportation and other motive power as well as electricity generation; (b) Energy profit ratio (EPR) for natural hydrocarbon stock relative to natural energy stock; (c) non-energy ecological footprint for biocapacity; and (d) water stress. These could usefully indicate the past and present state and trend of sustainability, thereby suggesting future limits to human activities.
Keywords: sustainability, operational principle, indicators, earth science, economics, geo-engineering
The sustainability of human civilisation has been framed in different ways within different disciplines. There remains considerable debate on how to best measure sustainability, even when limited to the physical and economic aspects of sustainability (Pezzey & Toman, 2005). Neoclassical economists and experts from other disciplines have proposed different measures to assess sustainability and resource scarcity. However, the major arguments presented in environmental or economic sustainability have not fully incorporated the findings of studies within the earth sciences-perhaps because the epistemic communities of each discipline do not closely overlap and because longer-term assessments such as 100 years or more, are not well addressed. Therefore, there is a need to reframe and re-examine the ideas from different schools in order to guide and assess policies, activities, investment and research and development towards sustainable development.
In Japan, the discourse and policy of environmental sustainability is framed as the three pillars of climate change mitigation and adaptation, sound material-cycle society and biological diversity conservation (Ministry of the Environment [MOE], 2011). However, this topical description of sustainability does not provide clear ideas and measures to determine the sense in which human society is environmentally sustainable or not, nor the critical thresholds that a sustainable society would need to respect. Moreover, current frameworks do not directly address the issue of securing the resources and energy inputs to economic activities. As such, the issue of climate change mitigation is not explicitly contextualised within efforts to transition to a society where only renewable energy is produced and consumed.
Global-level assessment of environmental sustainability also tends to be topical and is not physically integrated in ways that can be interpreted as a holistic system. Rockstrom et al. (2009) proposed the concept of planetary boundaries defined by nine issues, including climate change, biogeochemical flow and biodiversity loss. They provided tentative thresholds for these nine boundaries, three of which were already exceeded, according to their assessment. …