Environment Environment Society Economy Economy Society
Figure 2: Conceptual overview of T21-World
The environment, society and the economy represent the highest level of aggregation in the model (see left). Although our environment encompasses society and the economy, for simplicity we represent them separately in this report, to highlight the interconnections existing across them (see right).
By generating systemic, broad and cross-sectoral scenarios over time that address environmental, economic, and social issues in a single coherent framework, the global model simulates the main short-, medium- and longer-term impacts of investing in a green economy. As a global model without regional or national disaggregation, changes in geographical patterns of economic activity, social characteristics or environmental impacts are not explicitly represented (as explained in Annex 1). Furthermore the global model does not address explicitly the responsibilities or reactions of different actors, particularly governmental authorities.
The most important
contribution of this model is its systemic structure that includes endogenous links within and across
4. Feedback is a process whereby an initial cause ripples through a chain of causation ultimately to re-affect itself (Roberts et al. 1983).
the economic, social, and environmental
sectors (all defined at a global aggregate level) through a variety of feedback loops.4
models focus on one or two sectors, but make exogenous assumptions about other sectors that affect and are affected by the sector under consideration. Using endogenous formulations
consistency over time and across sectors, because changes in the main drivers of the system analysed are reflected throughout the model and analysis through feedback loops.