Summary
In this paper, an “emergy” (spelled with “m”) perspective is presented as suitable to address the green chemistry didactics toward a systemic conceptual framework. This emergy-based approach encompasses the three traditional dimensions of sustainability (environmental, social, and economic), including the upstream support of the geo-biosphere to human production processes.
The term “emergy” derives from “EMbodied enERGY”. The emergy analysis was applied to quite an extended range of systems in various disciplines, like ecology, economy, hard sciences, sociology, and many others. Emergy, defined as “the available energy of one kind that is used up in transformations directly and indirectly to make a product or service”. The concept of “emergy” is presented as well as the protocol used for emergy analysis of a system. This is organized in three steps: (1) Preparation of an emergy system diagram; (2) Preparation of an inventory table for the flows, each with the corresponding emergy values; (3) Evaluation and interpretation of suitable systemic indicators for the analysis purpose(s). Details and examples are provided in order to be clear the way that these steps can be organized.
Moreover, following the emergetic procedure, the emergy determination of a chemical compound will depend on the energy investment necessary to produce it, and this may vary significantly depending on the production procedures. The authors provide examples from the literature i.e. one utilized the emergy synthesis for evaluating the overall sustainability of chromium-based processes in tanneries, and the possible strategies toward a cleaner production, the production of artistic glass in Murano, etc.
Emergy analysis can be used in top-down educational approaches, for example, in teaching the environmental, toxicological, health, and sustainability issues that are at the basis of the green chemistry approach. On the other hand, emergy analysis is also well-suited for bottom-up paths, where one considers first the emergy of chemicals, and then the conceptual value and the use and outcomes of this determination. The authors propose two educational pathways, top-down and bottom-up, that can be implemented in specific curricula and adapted to the educational level that may range from secondary school to postgraduate teaching of chemistry. The paths for these approaches are outlined.
Emergy attracted criticism for the apparent lack of standardizations and for the difficulty in giving reliable uncertainty analyses, but most of all it is difficult to be conceptually fully understood at an undergraduate level. According to the authors this is related to the lack of systems thinking education at almost any level, whereas the intrinsically interdisciplinary nature of systems thinking should make it mandatory to develop the understanding of complexity.
Relevance for Complex Systems Knowledge
This paper deals with system thinking, interdisciplinarity and sustainability and proposes two “emergy” educational approaches that can be implemented in chemistry curricula. As suggested by the authors in both paths the following concepts should be included as part of an innovative chemistry course, aimed at linking chemistry to transdisciplinary issues concerning global socioenvironmental problems: One-world chemistry, Systems thinking, Multiple-scale, Circular economy and Green chemistry.
