Let us imagine a simple ecosystem. A seed germinates in the presence of sunlight and water. It becomes a tall tree while taking up nutrients from the soil with the help of other microorganisms. When the tree dies, its degradation releases the nutrients back to the soil, which are taken up by other growing trees and other micro-organisms, until they die and release the nutrients again … You will find many such closed loops in the nature.
Now imagine that our society is also an ecosystem. We take up our resources – fuel, water, etc. – from the ground and process them. After using them, we release them back in the system. The difference with the tree is that many of our resources leave us in a form that is difficult and expensive to re-use. Waste and pollution are results of an open loop system.
Industrial ecology is a concept that aims to close the open loops within socio-economic systems that lead to wasted resources and pollution of climate, air and waterways. For instance, in a place with water scarcity, could we use household waste water (the used resource of a system) to water agricultural fields (the primary resource of another system)? In principle yes! But under some conditions of course, such as the primary treatment of the water in order to avoid pathogen contamination.
I am looking forward to her talk on Sociometabolic regimes, revolutions and transitions on September 21st at the World Resource Forum to get more insight on those concepts.