Why Your Carbon Footprint Matters

Reducing your ecological footprint is essential as nations across the globe are consuming resources at a rate far exceeding what the earth can continually produce.


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“There is no more new frontier; we have got to make it here.” —Don Henley

In the thirteenth century, the Ancestral Puebloans (formerly called by their Navajo name, Anasazi) constructed natural homes, some large enough to accommodate 150 people, into the cliff faces of the high mesas of the Southwest’s Four Corners region. The mesas reveal a continuous human presence from about 550 A.D. to the late 1200s, but the magnificent cliff dwellings were not built until about 1200. Within less than 100 years, these sandstone dwellings were abandoned. Why?

Archeologists theorize the Ancestral Puebloans left in part because they had exhausted their resource base, which would have included timber (for building and as a fuel), soil (to support their extensive farming operations), and deer and other animals that supplemented their diet. Many researchers believe that at their peak (coincident with the time of their departure), the population of the Ancestral Puebloans was about 50,000 people, and that the piñon and juniper forest was essentially gone when they left.

Why would these people make such a tremendous effort to build the cliff dwellings if they could see that in a generation or two their resources would be exhausted? And secondly, how much intact forest was required to sustain a population of 50,000 people? Or by extension, how much land does it take to sustain an individual, whether that person is a thirteenth century aboriginal or a twenty-first century American?

This last question is a timely one. Are the earth’s resources adequate to sustain 6.2 billion people? And at what standard of living can these resources continuously support 6.2 billion people?

Measuring our impact

Citizens of developed nations across the globe are consuming resources at a rate far exceeding what the earth can continually produce and generating waste much faster than it can assimilate. We need to know the impact our lives and homes have on the planet, and we can do this through Ecological Footprinting, a model developed by Bill Rees of the University of British Columbia and his former student Mathis Wackernagel. It’s founded on two premises: that the resources we consume come from Earth, specifically from biologically productive land, and that the wastes we produce are assimilated by the same land. In other words, we don’t import resources from space (with the exception of the sun’s energy), nor do we send our waste into space.

Big foot, little foot: ecological footprint of selected nations

The Ecological Footprinting concept from Redefining Progress, a think tank in Oakland, California, measures the resources being consumed and the waste generated, then calculates the amount of biologically productive land necessary to sustain that flow and absorb the waste. For example, if you knew how many pounds of potatoes you ate each year, it would be fairly simple to calculate how much land must be in continuous production to supply you with the “flow” of vegetables. This would become your “potato footprint.” Add this to your meat, wheat, rice, dairy, fruit, and sugar consumption, and you have your “food footprint.” Do the same for your shelter, transportation, life- support services, and consumer goods consumption, and you have your total ecological footprint, measuring how many acres of biologically productive land it takes to support you on a continuous basis.

What’s your fair share?

It’s useful to examine the quantity of biologically productive land in relation to the number of people on earth to see how much land each person would enjoy if it were portioned equally. The United Nations reports there are about 28 billion acres of biologically productive land and sea space on the earth. Dividing this by roughly 6.2 billion people yields a per person share of just under 4.5 acres. People who have an ecological footprint of 4.5 acres or less are living within the means of nature, in other words, sustainably. Those whose footprint is greater than this are using resources and producing waste faster than can be sustained.

Footprint analyses clearly show that Western culture is very far from sustainability, citizens of some nations have a footprint well below their share, and the average world citizen lives beyond what the earth can sustain in the long run. Add to this that our population is growing exponentially, that our economy is growing even faster (despite the current recession), and that the earth’s biologically productive land is declining, and you have a recipe for collapse.

To effectively shrink our national footprint requires a concerted effort to reduce energy consumption and switch to renewable alternatives, and to redesign higher density major metropolitan areas to utilize mixed-use spaces and public transportation wisely.

The Ancestral Puebloans had no Ecological Footprinting tools to monitor their impact on nature—but they did have an escape plan. When their resource base was exhausted, they left and resettled in Arizona, ultimately establishing the Hopi and Zuni cultures. Our globalized society has no such escape opportunity. It’s up to us to change our ways.