How does human population affect society’s energetic metabolism

The energetic metabolism of societies and the degrowth paradigm: analyzing biophysical constraints and realities

Sorman and Giampietro analyze the implications, the feasibility and the desirability of possible trajectories of economic downscaling from an energetic perspective. The authors use the approach of societal metabolism to account for the profile of energy flows required and consumed by societies.

In this analysis, the authors explore the possible implications of demographic changes on societal metabolism. The model considers how “Demographic variables affect both: (i) the supply of working hours; and (ii) the requirement of working hours; within the metabolic pattern.” (p84). Based on the modeled implications of demographic changes, Sorman and Gioampietro find that, “population is and will remain a relevant variable to be considered,” even in the context of developed countries. The authors therefore urge degrowth proponents to more consistently consider the driver of human population.

ABSTRACT: The belief that it is possible to have a perpetual “economic growth” based on fossil energy has been challenged since the 1970s. However, only in the last decade is this issue re-emerging once again because of the predicaments of climate change and peak oil. Many, finally start to perceive that an “economic degrowth” entailing a downscaling of the current size and pattern of socio-economic systems seem unavoidable. In this paper we analyze the implications, the feasibility and the desirability of possible trajectories of downscaling from an energetic perspective. The quantitative analysis is based on the methodological approach of societal metabolism, and it provides a dynamic accounting of the profile of energy flows required and consumed by societies in relation the expression of a given set of societal functions. This analysis makes it possible to check two types of constraints: external constraints (supply and sink side limits for the whole) and internal constraints (the feasibility of energy budget of the various parts of the society expressing the required functions). The analysis of the metabolic pattern of a sample of developed countries is used to discuss possible implications of: (i) demographic changes; (ii) the declining supply of net energy sources, and (iii) the effects of the Jevons’ Paradox. Within such an analysis, a few assumptions and recipes of the degrowth movement seem problematic: (i) population is and will remain as a relevant variable to be considered; (ii) the proposed reduction in working hours seem to be impractical unless a major catastrophe will reset current civilization to pre-industrial standards; and (iii) voluntary reduction of personal energy consumption, even if a welcome adjustment, alone will not solve the existing problems. In the final part of the paper, future energetic road maps are questioned within the realm of post-normal science. Can we “plan” degrowth? If we are serious about the need of doing “something completely different”, societies will have to learn how to deliberate under uncertainty within the realms of flexible management and stop planning for either growth or degrowth. Moreover, before suggesting policies, it would be wise first to try to understand the option space.