We are constantly working toward greater understanding of our ecosystems but the complexity leaves even leading scientists to warn of unpredictability, especially with fast changes as we are seeing today. Needless to say, the mainstream understanding is a long way off. There are many notions about systems that we do not ordinarily think about, given our cultural tendency to define parts.
Unlike economic theories of substitutability, in many cases, removing just one key species from an ecosystem can mean the decline of the whole system.
Another component of systems are feedback loops. This is most often talked about with the notion of runaway climate change. As the climate warms, more ice melts, causing more light to be absorbed by earth, heating the earth more, again causing more ice to melt. As animals and plants die, there is less CO2 absorptive capacity and heating increases causing more death, causing more prolific Co2 and more heat. There are many feedback loops like this that relate to climate change. In an economic system we see obvious feedback loops in the stock market. Buying turns into more and more buying, as selling turns into more selling.
If a system is changing little overtime, the system is in equilibrium. Other components of systems include disturbances, such as fire or floods, and resilience, the ability to recover. Emergent properties can be likened to the notion that the sum is greater than the parts; For instance a tree is more than a mass of stored carbon. It provides structure for forest, habitat, moderates temperature, prevents erosion, cycles nutrients, etc…
Understanding these components of systems, we find key components in our current natural systems. For instance, according to Earth system and environmental scientists, led by Johan Rockstrom, nobel laureate Paul Crutzen, climate scientist James Hansen, and the German Chancellor’s chief climate adviser Hans Joachim Schellnuber, in order to maintain health on earth, the following earth systems must be held in check: climate change, biodiversity loss, biogeochemical balance, ocean acidification, land use, freshwater, ozone depletion, atmospheric aerosols, and chemical pollution contaminating the environment. At current climate change, the biogemical flow, and biodiversity loss are seen as being far past the boundary of safe operating space. The scientists who wrote this say that passing these thresholds leads to a risk of irreversible and abrupt environmental change. In order for the system to remain in equilibrium and avoid feedback loops, all of these components must be held within boundaries. Critics of the work are concerned that walking the line of these boundaries is too dangerous, and that avoiding boundaries does not justify environmental damage.