Environmental Science 101


"The science that studies the relationships and processes linking each living thing to the physical and chemical environment."
     - Barry Commoner, 1971, The Closing Circle
Environmental Science:

The Closing Circle: Nature, Man & Technology

Barry Commoner, 1971
“…the confusion [regarding the causes of environmental problems]…convinced me of the urgency of a deeper public understanding of the origins of the environment…”
“Such an understanding must begin at the source of life itself: the Earth’s thin skin of air, water, and soil, and the radiant solar fire that bathes it.”
“Living things…formed a global network, becoming deftly enmeshed in the surroundings they had themselves created. This is the ecosphere…Any living thing that hopes to live on the Earth must fit into the ecosphere or perish.”

The Four Laws of Ecology

First Law: Everything is connected to everything else.

There is one ecosphere for all living organisms and what affects one, affects all.
“The reciprocal interdependence of one life process on another.”
“Every living thing is…dependent on its physical and chemical…environment”
Nitrogen Cycle
- Fixation:
- Nitrification:
- Assimilation:
- Ammonification:
- Denitrification:
Other Biogeochemical Cycles

Ecosystems exhibit cycles
Natural cycles are self stabilizing
An externally forced imbalance in one part of this cycle can lead to disruption or collapse of the entire cycle.
The amount of stress an ecosystem can absorb is controlled by the amount of interconnections within the ecosystem.
The more complex the ecosystem, the more resistant it is to stress.

Second Law: Everything must go somewhere.

“There is no ‘waste’ in nature and there is no ‘away’ to which things can be thrown.”
This is a restatement of the basic laws of physics:
Law of Conservation of Energy:
Law of Conservation of Mass:
What is produced as “waste” by one organism, is taken up by another as nutrients, or accumulates as geologic strata.
Large amounts of materials have been extracted from nature by humans; converted into new forms; used; then “thrown away”.

Third Law: Nature knows best.

Nature has taken 3.5 billion years to develop the current global ecosystem.
Evolution via natural selection means that mutations have occurred.
These changes are either beneficial, neutral or harmful to the organism.
Harmful changes means the organism will not be successful and the species will go extinct.
Beneficial changes will mean continued success in fitting in to a given ecosystem.
Most changes have been unsuccessful.
99.99% of all once living species have gone extinct.
“…any major man-made change in a natural system is likely to be detrimental to that system”

Fourth Law: There is no such thing as a free lunch.

Economics of Ecology: Every gain comes with a cost.
The cost is always energy.
Exploitation of nature will inevitably involve the conversion of resources from useful to useless forms.