Integrated Modeling Analysis for Sustainability Assessment and Policy Decision Making

Successful implementation of sustainability ideas in systems management requires a basic understanding of the often nonlinear and non-intuitive relationships amongst different dimensions of sustainability, particularly the system-wide implications of human actions. This basic understanding further includes a sense of the time scale of possible future events and the limits of what is and is not likely to be possible. With this understanding, systematic approaches can then be used to develop policy guidelines for the system. This work presents an illustration of these ideas by analyzing an integrated ecological-economic-social model, which comprises various ecological (natural) and domesticated compartments representing species along with a macro-economic price setting model. The stable and qualitatively realistic model is used to analyze different relevant scenarios, which include gradual changes as well as sudden catastrophes. Apart from highlighting complex relationships within the system, it identifies potentially unsustainable future developments such as increased human per capita consumption rates. Fisher information, a measure based on information theory, is used to quantify the system-wide sustainability, and economic parameters in the system are shown to be strong predictors of future instability. Dynamic optimization is then used to develop time-dependent policy guidelines for the unsustainable scenarios using objective functions that aim to minimize fluctuations in the system's Fisher information. The results can help to identify effective policy parameters and highlight the trade-off between natural and domesticated compartments while managing such integrated systems. The results should also qualitatively guide further investigations in the area of system level studies and policy development.