ModEco - Model Economies

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For an overview of ModEco, read on.  Or, use the menu below to jump directly to one of the ModEco sub pages:

ModEco was conceived as a desk-top laboratory in which I and my students could explore the necessary and sufficient conditions for sustainable economies.  This was a major concern for the young people who could clearly see that (a) they needed to follow the standard plan for success, but at the same time (b) could see that the economies of the world are not doing very well.  In particular, they are worried about the accumulating ecological impacts of continued economic activity.   ModEco is a computer application that runs on Windows based computers.  


A ModEco-based economy consists of two dynamic subsystems functioning in tandem.  In the biophysical subsystem, economic agents harvest food (grain) from the field, eat it, then recycle the waste onto the fields again.  Mass and energy are conserved.  Agents reproduce (via fission), live, eat, and die of old age or starvation.  In the economic subsystem, economic agents use cash to facilitate all transfers of mass and energy.  Every exchange of goods or services is reciprocated with an exchange of cash.

When ModEco is started, there are a variety of out-of-the-box scenarios which can be modified prior to start.  In this scenario, I started with the Crowded scenario of the Cyclic economic engine, turned off the PMM switch, and hit the "Go" toolbar button.  The average economic profile of Frmrs and Wrkrs is shown at the bottom, displaying age, relative net worth, and asset class profiles.  At the right is a real-time display of the average bid-ask spread for those transactions being performed, each tick.

A ModEco-based economy has the following characteristics:

 - It is agent-based, having some characteristics of cellular automata, but economic agents can move from cell-to-cell under limited circumstances.  It therefore has some spatially constrained behaviour.

 - It is COMPLETE in two out of three ways:

     - End-to-end - mass and energy flow from farm to mouth and back to the farm in an endless cycle.  A new "linear" engine is in development, but the only sustainable model economy found so far is in the cyclic economic engine.

     - Top-to-bottom - both biophysical and economic subsystems must function together.

     - Front-to-back - humankind shares this world with many species, on most of whom we depend for our continued well-being.  ModEco-based economies do not exhibit completeness in this direction.  A truly sustainable economy must demonstrate the ability to preserve wild places and share the world with uneconomic species.  This is a critical need, at which our modern economies fail utterly, and these kinds of deep externalities are not modelled in ModEco.  I did not forget them.  I haven't gotten there yet.

 - It is "most simple", involving only a single commodity.  All features found in ModEco economies were added with the sole purpose of achieving a sustainable economy.  The goal is to identify necessary and sufficient features, to achieve sustainability, while, at the same time, having some metaphorical connection to real-world systems.

 - It is conservative, in that mass and energy are conserved, as is cash, in all transactions, and in the system as a whole.  The linear economic engine that is in development will demonstrate an open system, in which conservation at the level of the system is not maintained.  No sustainable economy has been demonstrated, to date, using such a linear economic engine.


A variety of reports, notes and papers describing ModEco, and analysing its output, can be found on the various pages in this section, or in the 'Interests' pages.

Last updated: September 2014.