Model Documentation - IFs
Note: The documentation of IFs is 'under review' and is not yet 'published'!| Corresponding documentation | |
|---|---|
| Previous versions | |
| Model information | |
| Model link | |
| Institution | Frederick S. Pardee Center for International Futures, University of Denver (Pardee Center), Colorado, USA, https://pardee.du.edu/. |
| Solution concept | |
| Solution method | Dynamic recursive with annual time steps through 2100. |
| Anticipation | Myopic |
International Futures (IFs) is a long-term integrated assessment system, which is a collection of multiple hard–linked, heavily interconnected models. Although sometimes referred to as modules, they are large-scale models in and of themselves. IFs represents 188 countries connected through a variety of flows, facilitates aggregation of them to global regions, and allows subdivision of them into more local socio-political units. It is dynamic recursive with annual time steps to 2100 and beyond (while myopic, many supply-demand equilibrating mechanisms with target specifications direct attention forward). The IFs system has an extensive user-friendly interface and is available for use by others both on-line and in a downloadable version, and it is open source.
The IFs system is extensively documented elsewhere. See Hughes (2019) for attention to the full system and the Frederick S. Pardee Institute for International Future’s website at https://korbel.du.edu/pardee for detailed model-by-model documentation. There is an interactive wiki at https://pardeewiki.du.edu/index.php?title=International_Futures_(IFs). Via Pardee’s website it is also possible freely to use IFs on line at https://www.ifs.du.edu/ifs/frm_MainMenu.aspx or to download IFs for use on machines with Windows operating systems from https://korbel.du.edu/pardee/content/download-ifs.
The purpose here is to provide a much shorter summary version of IFs documentation. Major models in IFs (see Figure 1 below) include
- a multistate population model, which represents 22 age sex cohorts to age 100+ and differentiates their educational attainment and cause-specific mortality patterns in the endogenous calculation of age-specific fertility and mortality.
- a multisector general equilibrium economic model, which uses inventories as buffer stocks and to provide price signals so that the model chases equilibrium over time; it provides labor, investment, and consumption information to partial equilibrium energy and agriculture models as well as GDP and GDP per capita (at market exchange rates and purchasing power parity) to all IFs models. Its structure contains a full social accounting matrix (SAM) representing financial flows among households, firms, and governments.
- an education model that tracks grade-by-grade student progression and aging of adults with variable attainment levels.
- a health model that represents age-sex specific mortality and morbidly by 15 causes of death.
- socio-political representations that include governance capacity and stability, as well as information on social values and cultural change.
- an international politics model that calculates multiple measures of national power plus patterns of interstate relationships, both positive and representing threat and conflict.
- an energy model (which portrays production of six energy types: oil, gas, coal, nuclear, hydroelectric, and other renewable). Physical values from the partial equilibrium model are converted to currency values to replace those in the general equilibrium economic model.
- an agricultural model, which is a partial equilibrium model in which food stocks buffer imbalances between production and consumption and determine price changes) the model represents crop, gazing, forest, developed and other land. As with energy, physical values converted to monetary values override selected sectoral values in the general equilibrium model..
- an infrastructure model that projects paved roads, access to safe water and sanitation, electricity access, and access to various forms of information and communications technology,
- an environmental model, which allows tracking of remaining resources of fossil fuels, area of forested land, water supply-demand, atmospheric carbon dioxide, and changes in temperature and precipitation.
- an implicit technology model with elements scattered across other models, which allows changes in assumptions about rates of technological advance in health, agriculture, energy, and the broader economy.
The variables shown as linking the models in Figure 1 are only a small subset of those that do so; the sections that explain the models will explain those and other linkage variables.
Figure 1: The basic models of the IFs system and illustrative linkages
Although other issues such as air quality, deforestation and species extinction have been very important, the very rapid development of Integrated Assessment Models (IAMs) during the 1980s, 1990s, and more recently was driven substantially by the recognition of the reality and danger of climate change. That and a call from the Intergovernmental Panel on Climate Change for a research organization focused on alternative climate futures led in 2007 to the establishment of the IAM Consortium. The Pardee Institute for International Futures is a member of the IAMC and IFs is an IAM. Its attention to energy, agriculture, and the environment reinforces its IAM character.
IFs differs, however, from most of the models developed and used by institutional members of the IAMC. Most of those models do not have elaborated demographic and economic treatment but rely instead on alternative scenarios of population and GDP futures generated by models specialized in producing those. The creation of Shared Socioeconomic Pathway scenarios (SSPs) has codified that use for most models. Similarly, attention to education and health is almost non-existent in other IAMs, and the attention in IFs to governance/socio-cultural change and international politics is unique. Across its developmental history, attention to broad sets of issues like those represented by the earlier Millenium Development Goals (MDGs) and the successor Sustainable Development Goals (SDGs) has motivated much of IFs development.
On the other hand, the treatment within IFs of environmental issues is considerably less developed than that of typical IAMs. That treatment is, however, of importance, and this document will provide summary details on it as well as on the other models in the IFs system.
A very important feature of the IFs system is that it is imbedded in an interactive user interface. The interface allows access to all the data that underlies model base-year initialization and facilitates estimation of functional forms, to a wide range of display options for examining results within and across model runs, and to a scenario-development interface for changing parameters within functional forms or more directly reshaping the behavior of model formulations via a wide range of multipliers and/or additive factors. The interface facilitates saving, retrieving, and modifying sets of scenario interventions, including direct exogenous specification of 11 or more key variables, including many that have come from quantification by other models focused on the Shared Socioeconomic Pathways (SSPs). The interface also facilitates saving, retrieving, and modifying resultant run files, as well as comparing runs files in research analyses and across model versions.
At https://ifsnetworkdiagram.du.edu is an interactive diagram that graphically shows the variables and parameters in the IFs models (modules) and allows exploration of causality and directional interconnection. More complete documentation of IFs is available on the Pardee Institute’s website at https://korbel.du.edu/pardee. A direct link to the IFs wiki is https://pardeewiki.du.edu/index.php?title=International_Futures_(IFs). Via the Pardee Institute’s website it is possible freely to use IFs on line at https://www.ifs.du.edu/ifs/frm_MainMenu.aspx or to download IFs for use on machines with Windows operating systems from https://korbel.du.edu/pardee/content/download-ifs.
The model code (but at this point not the interface code) is open source. For access to text files of the code and appropriate software to change it, contact the Pardee Institute and accept a general public use license that requires sharing code changes with the Institute. The programing language is vb.NET and the interface is built in asp.NET, which needs to run using Microsoft’s Internet Information Services (IIS).