Linear and Circular Economies

The economic model prevailing since the industrial revolution has been one that is described as a linear model, based on “extract-make-consume-discard.” The alternative circular model aims to decouple economic growth from the use of natural resources and ecosystems by using them more efficiently.

Sustainability

Sustainable development is defined (by the United Nations initially and now adopted by most nations) as “development which meets the needs of current generations, without compromising the ability of future generations to meet their own needs.” It is linked with renewability which is defined later.

Renewability

Renewability is defined as “any material or energy that can be replenished in full without loss or degradation in quality.” Biological as opposed to mineral and fossil raw material sources are preferred in the circular model, as they are seen as renewable

Table 1 The main levels of recycling that are generally recognized

and thus not finite. This simple definition is, however, coming under criticism. Plant sources are themselves finite and have many alternative uses, particularly for food production. Even where they do not directly compete, plants used for materials production occupy land which could often have been used for food crops. Finally there is a loss of biodiversity and habitat when land is cleared for their growth.