Sustainability is a term that’s used a lot in the discussion of the environment and environmental awareness. Quite literally, sustainability means the capacity to endure. In the context of ecology, it refers to how the earth’s systems — the very biology of the planet — maintain diversity and remain productive.
When we talk about the science of sustainability, it is essentially an issue of supply and demand. The earth supplies the essentials required for human and animal life: clean air, water and food. Over time, as human population and consumption have increased, the ability of the earth to supply these resources has declined. This has yielded significant environmental degradations evidenced in nature: land conversion and habitat destruction, species extinction, desertification, urban sprawl, overproduction of waste and hazards, toxification of water, air and land, ozone depletion and the greenhouse effect.
Scientists agree that the earth is a closed system to matter (solid, liquid, gas), which means there is no such thing as away. Nothing new appears and nothing ever disappears from the earth’s atmosphere although it may move from one place to another or change forms. While a closed system to matter, the earth is an open system to energy. The sun, which is outside our atmosphere, sends energy into the earth’s system, powering an elegant cycle of matter. Plants contain chloroplasts which, when powered by the sun, produce oxygen as well as carbohydrates, proteins and fats out of carbon dioxide and other waste products. Animals (including humans) produce the carbon dioxide which feeds plant life and in turn are nourished by what plants produce, both food and clean air.
Sustainability, then, is the running of this cycle in perpetuity. But humans have been intervening in and disrupting this system in four key ways – often referred to as system violations – causing nature’s processes to break down.
1. Humans are digging up material too quickly, faster than it can be reintroduced into the lithosphere by the process of sedimentation, which takes hundreds of years. Heavy metals, minerals and fossil fuels are being extracted from the earth’s crust at an alarming pace, even though we are uncertain of the supply available and know that these resources are not necessarily renewable, at least not in the span of a human generation.
2. Humans are poisoning the system by creating complex molecules that nature has never seen before and does not know how to break down when they are dumped into the biosphere. Things like plastic and polystyrene or chemicals like refrigerants and flame-retardants are persistent and unnatural substances. They are made by mixing chemicals together, making them no longer bio- degradable. These are then left in landfills and leak chemicals into the biosphere that proceed to harm plant and animal life.
3. By encroaching on natural areas, modifying ecosystems and harvesting renewable resources too quickly or aggressively, humans are degrading nature’s capacity to run its sun-driven cycles and provide clean air, water and good topsoil. Urban sprawl, insatiable appetites for trees and even some farming practices decrease biodiversity, compromise the soil and change the natural balance of species.
4. Although most of us in the Western world have seemingly unlimited easy access to natural resources, there are many others who experience the devastating effects of environmental degradation. Frequently, they are forced to further exploit nature in order to meet their basic human needs. As a result, ecological issues are not a priority for someone who cannot feed their family.
Disrupting nature compromises the system principles of sustainability. To avoid further damage, organizations and individuals must reduce or stop contributing to these four violations. We can reduce the pressures that negatively affect the earth.
 This information first appeared in A Study of The Salvation Army Canada & Bermuda Territory Environmental Policies and Practice, a project commissioned by the Office of the Chief Secretary and conducted by The Salvation Army Ethics Centre, September 2007.
Desertification is the process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture. To learn more about desertification and efforts to reverse this trend, check out this TED video.
 The lithosphere is the outermost shell of the planet itself, the earth’s crust.
 The biosphere is the part of the earth where life occurs, including land, water and air.