Global Systems Simulator (GSS)
GSS is a sophisticated integrated assessment model designed to explore avenues toward achieving sustainability by manipulating a wide range of factors, from population and production to agriculture and pollution. Relatively simple models such as these, flawed though they obviously are, can provoke useful thinking and discussion about how social and natural systems interact.
The Global Systems Simulator (GSS) is a simulation model, developed as a pedagogical tool with the intent of illustrating some of the concepts of sustainable development as applied to socioeconomic systems at the global scale. Conceptual clarity is achieved through the abstraction of the major elements of a given system. Accordingly, in this model, the global socioeconomic system has been abstracted down to the following processes that are required to illustrate the links between the environment and the economy:
- population growth;
- food and durable consumption;
- food and durable production;
- recycling;
- pollution treatment;
- renewable energy production;
- nonrenewable energy production;
- resource production;
- research into primary sector and secondary processes.
A unique feature of the design approach taken with this model is that the system of feedbacks among all the processes represented is incomplete. The resulting discord, disequilibrium, or tension that arises from this structuring allows questions to be asked about why these tensions are appearing. Therefore, instead of the model providing a solution, the student is provided with an opportunity to prototype creative responses to complex systemic challenges. This makes the student an extension of and an integral part of the modeling process. When this approach is applied to a group of students, opportunities for discussion around differing worldviews and problem-solving strategies arise, highlighting that effective action depends on actors having a common understanding of the system in view, or a shared systems model.
This process of prototyping solutions allows students to ask questions of the system and then to analyze the response. Some of the system’s responses may be what the student was expecting, while others may be counterintuitive or even unexpected. Unexpected results can vary as well. Some actions result in unexpected changes in other tensions while some actions result in a magnitude change that was either larger or smaller than expected. Overall, each iteration builds the student’s understanding of the dynamics inherent in the system being modeled.
Possible Tasks
- Each team is to work together to generate two different balanced and “livable” scenarios (i.e. socially equitable and environmentally sustainable). You will be asked to create vision statements regarding the nature of your scenarios, i.e. to develop the two scenarios along two different basic policy goals.
- Test your two scenarios for robustness to unexpected events, such as a global epidemic, a war, or a serious environmental disaster.
- Explore what the desirable features of each scenario are—do either of them favor particular groups or sectors? Are there implicit social, economic, or environmental issues left unresolved in these scenarios?
- Explore which scenario has the more desirable transient response (“the path of getting there”) and which has the more desirable long-term results, indicating in what sense you mean “desirable,” in which dimensions, for whom, and according to what criteria.
- Consider which scenario would be easier to implement. Support from whom, or what system, would be needed to implement either of your scenarios? What kind of adaptive strategy would need to be included in the implementation of your plan? How could one create conditions now so that an adaptive implementation strategy is more likely to be followed over time?
Translating a Narrative into a Model
Stories are woven into all cultures and societies and are an important medium for passing on information and, more importantly, knowledge. Models are also a medium in which stories are contained and relayed. In short, models start from stories and tell stories. The story starts like this. Sustainability is a property that is found within our socioeconomic system and is bound by the limits of the physical systems of the Earth. It is a dynamic property in that it applies to the trajectory of the system. Therefore, in order to determine whether our current socioeconomic system has the property of sustainability, we need to be able to examine the system’s future evolutionary paths.
Sustainability is a concept that implicitly includes a time dynamic—namely, it applies to the trajectory of a system. In order to determine whether a socioeconomic system has the property of sustainability, it is necessary to examine its future evolution path. However, the future evolution path, in part, will result from human activities that are subject to choices which will be made in the future. Therefore, it is necessary to examine possible evolution paths that are contingent upon societal choices.
Selected Participants’ Feedback
GSS has a built-in model of the world’s “stocks and fluxes”: population, food, durables, natural resources, forests, agricultural land, etc. The stocks and fluxes were calculated based on historical data that were collected by many institutions. The data is also present in the model, so that, for each quantity, you can plot a chronological graph. You cannot change this past, but you have a series of “control panels” to visualize the “future” of this model. The default future is called “business as usual” (BAU), and it includes four main “tensions.” A tension is an incompatibility between the required and the available stocks of something: crops, wood, energy, and labor are the quantities that undergo enormous tensions in the BAU future. You can modify this future and create alternative scenarios by visualizing and modifying the curves and by seeing what happens. [. . .] Something I discovered is a dramatic fall of wood availability in the near future. I didn’t expect that. I always saw forests as an “engine” for photosynthesis, and therefore as a major factor influencing the composition of the atmosphere (by the way, atmosphere composition is not explicitly modeled in GSS). Instead, wood is required by humans for energy production and for constructions of all kinds. So much so that we cannot save the modeled trees without dramatically dropping the modeled society’s demand for wood. It is not even enough to start planting and replanting forests everywhere because of the time lag implied for the trees to grow.
- Sustainability can indeed be achieved (most of the so-called “tensions” can be resolved in the context of the model). However, doing so requires a massive (and arguably impractical) reduction in per capita consumption and population.
- It was a (quantitative) revelation that even if we could effect immediate and significant changes in our societal values and transit to a low-consumption society, we would still not necessarily be able to nullify ecological overshoot for a significant amount of time.
