In the saga of Harry Potter, the Marauder’s Map allows the magician to reveal the whereabouts of any person in space, covering all the levels (floors) of the castle, its secret passages, as well as the surrounding grounds. The term marauder (i.e., a plunderer1) neatly reflects the roving nature of the scientist involved in multi-scale transdisciplinary assessment. The resource nexus requires the scientist to identify relevant descriptive domains and reconcile top-down and bottom-up assessments, thereby providing meaning and coherence to the various sets of non-equivalent data required for informing policy across scales and dimensions. In this sense, the Nexus Structuring Space, developed in MAGIC, can be considered a sort of Marauder’s Map guiding the use of the MuSIASEM2 tool-kit for the analysis of the nexus. It allows the analyst to move quantitative assessments across levels and dimensions to check the feasibility, viability, desirability and openness of the metabolic pattern of a social-ecological system.
Figure 1 shows an overview of the functioning of the Nexus Structuring Space and its ability to identify, as in the Marauder’s Map, the sources of information that are relevant for different research questions. Starting from the left, we see the information available when looking through the macroscope. On the top left, we see the entanglement over the activity of the constituent components of the system (agriculture, energy and mining, manufacturing and construction, service and government, and the household sector). They are producing and consuming the inputs for/from each other. In MAGIC, we define a socio-economic system as “a metabolic network in which constituent components stabilize each other in an impredicative (self-referential) set of relations in presence of favorable boundary conditions” [1, 2]. A quantitative representation of the forced metabolic relations across the elements of the constituent components is obtained by characterizing these forced relations in an end-use matrix. Using the macroscope, the end-use matrix allows us to see: (i) who is using either energy, food, water; (ii) why; (iii) how much; and (iv) how. The end-use matrix thus allows the establishment of a bridge with demographic variables (i.e. the demographic structure) and characterizes the profile of distribution of the secondary inputs among the different constituent compartments. The resulting concept of Bio-Economic Pressure (Figure 1) indicates that economic development requires a significant fraction of internal resources to be allocated to final consumption and to the service sector.
Looking through the mesoscope, we can identify other sources of information that permit an analysis of the level of openness of the system determined by trade (see Figure 1). Here, we have to change the categories of accounting and use another metric (metric #2) to assess the flow of commodities. Through the lens of the mesoscope we study how much of the production of internal inputs in the various constituent components of the system is due to local processes or to imports. After having clarified this point, we look at the system through the virtualscope to characterize what exactly is required in terms of end-uses and environmental pressures to produce the local secondary inputs inside the system and what is required in terms of end-uses and environmental pressures to produce the imported commodities (right hand side of Figure 1).
To identify the sources of useful information for this assessment we have to move to yet another set of descriptive domains, which are illustrated in Figure 2. Starting from the left of Figure 2, and using as inputs the overall required supply of commodities observed through the mesoscope and measured in metric #2, we can associate the set of commodities locally consumed to a set of production processes required for their production. At this point, we need to look through the microscope to visualize, at the local scale, the profile of inputs and outputs associated with each of the local processes. These inputs and outputs can go: (i) inside and outside the technosphere (secondary flows that are relevant for the socio-economic process); and (ii) inside and outside of the biosphere (primary flows that are relevant for the compatibility with ecological processes). When observing local processes with the microscope we can geo-localize these processes and check whether the environmental pressures associated with the primary flows exchanged with the biosphere – both on the supply and sink side – are compatible with local ecological funds and therefore assess the resulting environmental impacts.
In conclusion, when dealing with the analysis of the nexus, depending on the research question, we can use a logical map —the Nexus Structuring Space — to guide our search for and use of data from among the available sources of information. The Nexus Structuring Space shows the role of the various available grammars in MuSIASEM (specified sets of expected relations over metabolic processes) and helps the analyst to identify the type of data that is relevant to generate the desired types of result.
More information on the toolkit and its applications is available in MAGIC Deliverable 4.4.
1 One who roams from place to place making attacks and raids in search of plunder (https://www.merriam-webster.com/dictionary/marauder)
2 MuSIASEM: Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism
 Giampietro, M., Renner, A., 2020. The Generation of Meaning and Preservation of Identity in Complex Adaptive Systems: The LIPHE4 Criteria, in: Braha, D., et al (Eds.), Unifying Themes in Complex Systems X: Proceedings of the Tenth International Conference on Complex Systems. Springer (Series: Springer Proceedings in Complexity), Cham, Switzerland
 Renner, A., Giampietro, M., Louie, A.H., 2020. Cyborgization of modern social-economic systems: Accounting for changes in metabolic identity, in: Braha, D., et al (Eds.), Unifying Themes in Complex Systems X: Proceedings of the Tenth International Conference on Complex Systems. Springer (Series: Springer Proceedings in Complexity), Cham, Switzerland