Ecological Footprints Laboratory Exercise
Like all species, humans need certain resources to survive. However, humans consume resourcesnot only for survival, but also for comfort, luxury and prestige. Whereas non-human species generally must obtain their resources from within their ecosystem, in contrast, humans have derived ways (transportation) to remove resources from other ecosystems to satisfy their wants and desires. However, societies are not equal in their ability to extract, transport, process, manufacture, and use resources. And, societies have different philosophies and cultural perspectives regarding their desire to utilize resources beyond basic needs. Thus, there is a question of equitable distribution of resources among human societies and between humans and other species.
In addition to resource extraction, an additional crucial ecosystem function is the assimilation of wastes (e.g. air, water and soil pollution; hazardous, solid and radioactive waste; and waste heat). Again humans have devised ways to discharge wastes into other ecosystems by building tall smoke stacks, dumping waste in flowing rivers and oceans, and shipping wastes around the world.
The area of productive land required to provide resources and assimilate waste to meet consumption needs is referred to as the ecological footprint (Wackernagel and Rees, 1996(). This is different from the carrying capacity, which is the maximum abundance of a population that can be sustained by a habitat or ecosystem without degrading the habitat or ecosystem. Because non-humans cannot extract resources from outside their ecosystem, their population cannot exceed the carrying capacity, which is based on the availability and amount of an ecosystem’s resources. Thus, a non-human’s ecological footprint is limited by the size of the ecosystem. In contrast humans have a carrying capacity for their “ecosystem” (for example, a country). However, because humans can transfer resources from another country, their ecological footprint can exceed the carrying capacity. Thus, the United States’ ecological footprint can exceed the carrying capacity of the United States (i.e. the U. S. can maintain more people than available resources) because resources are extracted from Mexico, Africa, Saudi Arabia, and so forth. Clearly this means that for some countries, their ecological footprint must be smaller than the carrying capacity because the Earth has a finite amount of resources. Or, some populations must live near the subsistence level, whereas others can live in high comfort.
The ecological footprint is one measure of the sustainability of a society’s current lifestyle. However, this is an anthropocentric view. If humans consume all the resources or take over all the biologically productive land, what about non-humans? And what about humans in less developed countries? This is an issue of environmental equity. In developing nations such as India, about one hectare is needed to meet the resources requirements of an average person. In the United States, the average individual ecological foot print is 9 hectares (23 acres). If everyone in the world consumed resources equal to the average American, we could need ~5 Earths.
Name: ______Due in lecture one week from today
- Go to the following website to calculate your ecological footprint:
- Fill in your results below.
Footprint Global Acres: ______
Number of planets needed: ______
- In what areas (energy, crop, grazing, etc.) do you consume the most land? Do the results about what types of “land” you consume most surprise you? Why or why not?
- How does your footprint compare to the average American footprint of 23 acres? Why do you think you are higher or lower than the average American?
- How can reduce your ecological footprint most effectively? (Hint: Explore other scenarios and/or change some of the answers in the quiz to see how this changes your footprint). What constraints may keep you from reducing your consumption any further?
- How do you feel about your consumption pattern and how it affects other humans on Earth? Do you think that you have an moral obligation to reduce your footprint?
- Does this exercise make you want to change your lifestyle slightly? What might you work on changing right away?
References cited:
Wackernagel, M. and W. Rees. 1996. Our ecological footprint: Reducing human impact on the Earth. New Society Publishers, British Columbia, Canada.
Adapted from Wagner, T. and R. Sanford. 2005. Environmental Science: Active learning laboratories and applied problem sets. John Wiley & Sons, Hoboken, NJ.