We have a noisy debate going on in this country about what environmental problems we face, what causes them, how to take care of our environment, what parts of it we should take care of at all, etc.
In order not to contribute to the already toxically high decibel arguments based on political stance or economic interests, it helps to keep in mind some basic scientific facts and understand some basic scientific terms, such as “ecosystem.”
The “eco” in ecosystem is the same root as “ecology” or “economics.” It means habitat or household.
A system comprising a habitat or household is a set of components related to that habitat or household arranged in such a way that they work together to accomplish some purpose. As far as the root meaning of the word goes, an ecosystem could be a house, the people in it, their pets and houseplants, other living things (bugs, germs, whatever) along with the electricity, plumbing, and other systems built into the house.
No one uses the term that way, but the house analogy has some important concepts that directly help us understand an ecosystem in its usual meaning: It includes both living and non-living things. It comprises everything present. The proper functioning of systems in the house depends things outside the system. The weather, for example, or an accident that knocks over a power pole.
Strictly speaking, the whole earth is an ecosystem. It’s a habitat. Plants and animals (including humans) live on it. It also has numerous non-living things, including some that are indispensable to support life: air and water to name just two. Life on earth also depends on the sun, which is not part of earth.
That said, the earth is an ecosystem, not the ecosystem. Conditions for life in a jungle, a desert, a fresh-water lake, a salt-water ocean, etc. are all noticeably different. If fact, recently discovered life forms at the bottom of the ocean differ greatly from the more familiar life forms nearer the surface. So we speak of an ecosystem as some kind of definable unit distinctly different from other ecosystems.
All ecosystems rely on energy from the sun. Plants make food (specifically, sugar and starch) from sunlight by a process known as photosynthesis. They draw other nutrients from the soil, and from these sources use some of the energy immediately and store some for future use.
Some animals get food for themselves by eating parts of the plant: fruit, seeds, leaves, roots, etc. Other animals cannot eat plants, but they can eat plant-eating animals. Animals, too, use some of the energy they get from food immediately and store some.
Eventually, all living organisms die and return nutrients to the soil as microscopic beings eat the remains. Plants take up the nutrients and begin the cycle all over again. So long as the both the need for and supply of various parts of the chain maintain a proper balance, the ecosystem can sustain itself indefinitely.
If something upsets the balance, the system eventually collapses. Ecosystems arose, flourished, and ceased to exist long before the dawn of history.
The emergence of humans, however, has inserted some complexities into their operation. Well before the start of the Industrial Revolution, mankind was clever enough to over-hunt an area, use slash and burn agricultural techniques, or otherwise upset the equilibrium in an ecosystem. We can now take an organic substance, petroleum for instance, and turn it into plastics that cannot decay and return nutrients to the soil for plants to use as energy.
I will not attempt to enumerate all the ways that humans have become capable of disturbing an ecosystem. To whatever extent human activity hampers the normal functioning and balance of the natural world, it causes an unsustainable imbalance.
If we are clever enough to build technologies that cause problems, we ought to be clever enough to tweak them and make them sustainable.
We as individuals cannot afford to wait for our political leaders to agree on solutions—especially considering that Americans have enabled legislators to make safe seats for themselves that render them more beholden to outside pressure groups than to their constituents.