Each connecting line in the IFF World Model implies:
- The factors on each end of the line reciprocally influence each other. A change in one is likely to induce a change in the other and the influence may work either way (for example, climate change will affect biosphere which in turn affects climate);
- Not all these mutual influences will be of the same strength or the same type. Only some of them will affect the world system beyond its resilience to return to an average state (for example, trade and wealth may oscillate together but more or less keep in step);
- Changes can propagate themselves across the network (for example, water shortage can affect food production can affect wellbeing can provoke governance issues around providing aid);
- Changes can occur in a factor that are discontinuous and may shake the whole system (for example the implications and impact of peak oil in energy);
- Discontinuous changes could occur in more than one factor at a time. This is known as synchronous failure (for example climate events at the same time as economic collapse).
These influences can be grouped into two main kinds:
1st Order Effects are those that occur within a given factor. Especially of interest in the modelling are discontinuities or tipping points. An example in energy would be peak oil. An example in climate change would be carbon dioxide emissions triggering rapid release of methane.
2nd Order Effects are interactions between any two or more of the factors. These effects create a more complex aspect in the overall problematique. An example might be that the invention of abundant cheap energy (desirable for a number of good reasons) also carries the knock-on danger of over-pumping of aquifers, grid-locked mobility, appropriation by despotic military or terrorists and so on.