A Model of Environmental Stress: Tracing Causes & Effects

Many environmental stresses appear to have simple causes and effects; for example:

proximate cause	environmental stress	proximate effects
"consume" lots of material goods	solid wastes pile up (optional photo)	land-filling incineration recycling

Most environmental stresses have complex causes & consequences; for instance:

In the above diagram only the effects of plastic bottles accumulating are noted, that is, downstream from or after the stress of accumulation.

Processes that precede and lead to the piling up of plastic bottles may also have significant environmental effects. These may be called upstream effects.

In the above example, what upstream effects might we identify, in addition to the downstream effects which are diagrammed in the model? To answer the question, first try to list the major processes that must occur in order for plasic bottles to accumulate. Then attempt to determine the environmental consequences of each of these necessary upstream acts. For instance:

Some processes necessary for plastic bottles to pile up	Some environmental effects of such action-- upstream effects
Extract petroleum from which to make plastics	Oil spills
Make petrochemicals	Air pollution, water pollution
Make plastic bottles	Air pollution, electricity use
Ship containers to bottler	Transportation impacts
Produce beverages (contents)	Resource use for contents
Bottle beverages	Impacts of making and operating bottling equipment
Truck beverages to retailer	Transportation impacts, including energy use
Store beverages at retailer	Energy used for lights, refrigeration, store operation
Purchase and consume contents	Possible health effects
Dispose of plastic bottle (after one use!)	Energy and other costs of handling waste bottles

A written description, but analogous to our model in terms of sifting out important effects of a common practice-- eating commercial french fries-- is online for you to read ["French Fries" section only-- it's about 1/3 the way down the online page; 800 words]. This brief analysis is condensed from a chapter in Stuff; The Secret Lives of Everyday Things, by John C. Ryan and A.T. Durning, 1997, Northwest Environmental Watch, Seattle. The book also analyzes the environmental costs of coffee, newspaper, T-shirt, shoes, bike and car, computer, hamburger, and cola.

Despite our "broader and deeper" view of causes and effects of environmental stress, reality is usually much more complex than such models suggest. Webs of cause-and-effect linkages are more realistic than an isolated, linear chain of links.

A major fault with our linear model is that it largely fails to recognize feedback loops, whereby one factor influences other processes, which in turn interact and circle back to change the initial factor. This dynamic interaction is inherent in nearly all environmental issues, but it is virtually impossible to comprehend in detail.

Using computers, extremely complex models with thousands of interacting variables are sometimes employed in an attempt to simulate and understand real-world problems. Such models are beyond our consideration in this course.

Thomas Detwyler maintains this page (tdetwyle@uwsp.edu)
Last updated 29 January 2001

basic causes	general causes	proximate causes	*enviro stress*	proximate effects	general effects	extended effects
corporate capitalism	producer’s profits	consume lots of beverages in plastic bottles	plastic bottles pile up		dioxins emitted toxic ash
ignorance	no perceived harm			(land-filling)		human illnesses + + +
attitude	consumer convenience			incineration		ecosystem damage + + +
population growth	more production/use			(recycling)		hazardous waste polln
technology	new materials