Integrated model for food-energy-water (FEW) nexus to study global sustainability: The main generalized global sustainability model (GGSM)

Abstract

Over the years, several global models have been proposed to forecast global sustainability, provide a framework for sustainable policy-making, or to study sustainability across the FEW nexus. An integrated model is presented here with components like food-web ecosystem dynamics, microeconomics components, including energy producers and industries, and various socio-techno-economic policy dimensions. The model consists of 15 compartments representing a simplified ecological food-web set in a macroeconomic framework along with a rudimentary legal system. The food-web is modeled by Lotka–Volterra type expressions, whereas the economy is represented by a price-setting model wherein firms and human households attempt to maximize their economic well-being. The model development is done using global-scale data for stocks and flows of food, energy, and water, which were used to parameterize this model. Appropriate proportions for some of the ecological compartments like herbivores and carnivores are used to model those compartments. The modeling of the human compartment was carried out using historical data for the global mortality rate. Historical data were used to parameterize the model. Data for key variables like the human population, GDP growth, greenhouse gases like CO2 and NOX emissions were used to validate the model. The model was then used to make long-term forecasts and to study global sustainability over an extended time. The purpose of this study was to create a global model which can provide techno-socio-economic policy solutions for global sustainability. Further, scenario analysis was conducted for cases where the human population or human consumption increases rapidly to observe the impact on the sustainability of the planet over the next century. The results indicated that the planet can support increased population if the per capita consumption levels do not rise. However, increased consumption resulted in exhaustion of natural resources and increased the CO2 emissions by a multiple of 100.

Evaluation of global techno-socio-economic policies for the FEW nexus with an optimal control based approach

“…In this study, we utilize an integrated assessment model known as the generalized global sustainability model (GGSM) (Hanumante et al, 2022;Nisal et al, 2022) and optimal control methods to derive policy options elemental toward achieving sustainability. The model is available here.…”

“…Further details of this model can be found in Hanumante et al (2022) and Nisal et al (2022). This model was reparameterized recently to present a more realistic system.…”

“…The model starts in the year 1950 and the per capita consumption increase scenario starts in the year 2020 (Hanumante et al, 2022;Nisal et al, 2022). Hence, the optimal control strategy starts from the year 2020 and goes till 2150 for a total of 130 years.…”

“…The optimal values of the policy parameters are then utilized to evaluate the nature of all the model compartments and performance on the objectives. These results are compared to the scenario analysis results for the uncontrolled per capita consumption increase scenario (Scenario 3) (Nisal et al, 2022).…”

Integrated model for Food-Energy-Water (FEW) nexus to study global sustainability: The water compartments and water stress analysis

“…Some of the other notable examples of global models are GUMBO [12], Earth3 [13], and HANDY [14]. More recently, Nisal et al [15] developed the Generalized Global Sustainability Model (GGSM). As compared to other global models, GGSM's ecological dimension is represented with features such as multiple trophic levels and intra-trophic level diversity.…”