Environmental Associates
Know Your Environment
Tracks on the Land: Measuring "Ecological Footprints"
Let Us See How We Leave Our Mark On the Earth
by Roland Wall
Introduction
How would you like to own a piece of land that's a mile long and a half-city-block wide? Its very expensive and—better yet—it constantly generates new revenue. An ad for it would read: "Twenty-one exclusive acres devoted to maintaining your lifestyle."
Who wouldn't want to have some real estate like that?
If you're an American, you might be surprised to learn that you already do. Don't expect, however, to walk the boundaries of your estate any time soon. It's not all in one place.
Are you a coffee drinker? Then a square inch of "your" land may be in Columbia. Wearing wool socks? You own a few blades of grass in a pasture in Scotland. Read a newspaper? That's your sliver of a pulp wood farm in Arkansas.
If this sounds fanciful or abstract, it is neither. Rather, this kind of calculation represents one of the newest ways of assessing the impact that humans have on the global environment. Your twenty football-fields of land are what it takes to maintain a single, average American lifestyle. The concept is called an "ecological footprint."
Twenty Football Fields
The originators of the term describe an ecological footprint as being, for any given population, ".the biologically productive land and water area occupied exclusively to produce the resources consumed and to assimilate the wastes generated by that population, using prevailing technology." [1]
The use of ecological footprinting works from two hypotheses. First, that there are reliable methods for approximating the average amount of resources each person of a population uses and the waste that they generate. Second, as a corollary, this quantity can be related to a hypothetical area of land needed to perform those functions.
Calculating ecological footprints can become very complicated and there will almost certainly be refinements in the future. Investigators thus far however, have tended to err on the side of caution, suggesting that footprints could be larger than stated.
The final results are easily understood. Because ecological impact is always expressed in terms of the amount of productive land used per person, comparisons can be made across many scales and contexts. Populations can be any number of people, from a family to all of humanity.
A study entitled "Ecological Footprints of Nations," commissioned in 1997 by the Earth Council, compared the ecological footprints of the populations of 52 countries with the amount of productive land available per person in each nation (or per capita ecological capacity.)
It was this study that showed that each person in the U.S. required 21`acres of productive land to support their level of consumption and waste production. Per capita, however, the U.S., only has about 16 acres of such land available, making an "ecological deficit" of 5 acres per person. This means that citizens of the U.S. are depending on a quarter of their ecological needs being met outside of the country.
Other industrial nations, such as Germany and Russia, had similar deficits. A few, like Japan, had deficits that were even higher. On the other hand, some developing nations, like India and China, had footprints of only a few acres, and no national ecological deficit. [2]
While there is no means of tracing where each piece of a nation's footprint originates, these figures do indicate the global flow of resource distribution. Ultimately, everything we use has to come from somewhere.
The footprints also highlight that the impact of a citizen of an industrialized nation can be disproportionate compared to citizens in the developing world. In terms of resource consumption, each European might be said to "occupy" as much space as five people in China.
One defining feature of the ecological footprint is that it is based on available levels of productive land per person. This is more meaningful than simply looking at population densities. While optimists sometimes downplay resource issues by noting the vast land areas worldwide compared to the total global population, the proportion becomes considerably smaller when looking at the amount of land that is actually available to provide ecological services (eg. to grow food, recycle oxygen).
According to the "Nations" study, there are essentially six categories of land that can meet these needs: cropland, pasture, forest, shallow seas, built-up regions and fossil energy land. When the estimated areas of these productive categories of land are totaled and averaged over the population of the world, it comes out to just five and one half acres per person. Unfortunately, this is over an acre less than the size of the average per capita ecological footprint of the world's population.
Put another way, the entire Earth runs an on-going ecological deficit. This is possible for the present because humans are able to make use of ecological services in a non-renewable manner - clearing forests, increasing the levels of carbon dioxide in the atmosphere, "strip mining" fisheries faster than they can reproduce. This has been described as "spending nature's capital" rather than living off the "interest."
These calculations make clear, however, that the natural systems cannot continue to supply these ecological services at the current rate of use. They demonstrate that if the size of each person's ecological footprint continues to grow, the level of demand for these resources and services will rise at a much faster rate.
Growth in the global footprint could come from two related sources - increased population and expanded consumption. An increase in global population seems inevitable at this point, and—if current economic growth continues to be tied to consumption—expansion of resource use seems likely as well. Even at current rates of consumption, the area of productive land would drop to just 3 acres per capita if the world population crosses 10 billion, as it is expected to do in 2050.
And while it is certainly hoped that the global standard of living will continue to rise, if an improved quality of life requires that developing countries adopt higher levels of consumption, the results will drastically increase the size of the global ecological footprint. If everyone consumed resources and generated waste at the rate of many of the industrialized nations, productive land would quickly be overwhelmed. In fact, these analyses estimate that if all of the 6 billion people now on the planet had ecological footprints the size of Western nations, it would require two more Earths to meet their ecological needs.
Moreover, these figures do not include productive land for any of the other 5 to 30 million species with whom humans must share space. The study notes that the UN's World Commission on Development and the Environment has recommended that a minimum of 12% of the planet should be maintained for the protection of biodiversity. If that is factored in, the current level of per capita productive land drops to less than 5 acres. In fact, the rising rate of species extinction can be thought of as an indicator that human actions are dipping into natural capital.
The point of these calculations and estimates is not, however, to engender a sense of doom, nor to elicit guilt from the wealthier nations over their consumption habits. While it is important for all populations, from individuals to nations, to understand the impact of their actions, the use of footprinting also gives important insight into correcting ecological problems.
First, it provides an easily understood set of reference points for examining the sources of environmental problems. On a global level, ecological threats can be traced to four factors - too many people consuming resources, too many resources being consumed, inefficient and wasteful uses of resources by consumers, and insufficient bio-physical productivity per unit of land.
Decreasing the first two factors—population growth and rates of consumption—will probably require long term changes in social and behavioral habits. The second two, however (improving efficiency of productivity and consumption), lend themselves to simpler, technologically based solutions. Innovations like efficient lighting, industrial waste recycling and hybrid automobiles may seem like "gimmicks," but can have significant effects when translated into a population's ecological footprint size. They particularly offer stop-gap solutions to buy time as societies decide how best to manage their ecological needs.
Most importantly, the ecological footprint provides a measurable standard for evaluating the current state of human impacts on the global ecosystem and for assessing progress towards mitigating those impacts. Though there have long been indexes such as the Unemployment Rate or the Gross Domestic Product for measuring economic health and progress, human ecology has lacked such clear and accessible standards.
As nations and groups have become aware of threats to the global ecosystem, there has been a growing call for protecting the "sustainability" of human and natural systems. While the ecological footprint will certainly not be the last word in measuring sustainability, it does provide an initial tool for assessing this elusive quantity. For those concerned about the environment, measuring footprints may soon become as automatic as re-cycling or picking up litter.
References
- Wackernagel, M. 1999. What We Use and What We Have: Ecological Footprint and Ecological
Capacity.
www.rprogress.org/progsum/nip/ef/ef_projsum.html [go back] - Wackernagel, M, L. Onisto, A. Linares, I. Falfán, J. García, A. Guerrero, Ma. G. Guerrero. 1997. Ecological Footprints of Nations: How Much Nature Do They Use? How Much Nature Do They Have? Commissioned by the Earth Council for the Rio+5 Forum. Toronto: International Council for Local Environmental Initiatives [go back]
Further Reading
- Wackernagel, Mathis, and William E. Rees. 1996. Our Ecological Footprint: Reducing Human Impact on the Earth. Gabriola Island, BC: New Society Publishers.