Basic Causal Linkages

Abstract

Figure 5.1 provides a first clue to the causal interactions between the M^aa- and M^a-levels. The M^aa-level, designated by area A, shows the ratios between population P and the eco-variables land N, nonrenewable resources R, and carrying capacity of the environment C. The impact on the ecosystem S _c by population P is expressed by the aggregate ratio P/S _c . The link to the M^a-level, embracing area B, is given by Ā and k. Ā stands for average consumption and production activities, and k is a coefficient which expresses the degree to which Ā and P affect S _c (see section on Social Choice in a Finite World, pp. 99–107). Ā and k depend on the M^a-systems S _e , S _s , and S _t . The overall eco-ratio ĀkP/S _c exerts feedbacks on the population system— for instance, the Malthusian food-population feedback. The overall eco-ratio exerts, furthermore, feedbacks on the M^a-system—for instance, responses to counter the Malthusian threat or adapting production and consumption activities to changed environmental and natural-resource conditions. To some extent, the eco-variables N, R, and C may be altered by policies (as denoted by the broken lines from the systems S _e , S _s , and S _t )—for instance, intensification of new resource recoveries, etc.