Leave Nothing But Footprints?
Ecological thoughts about human economies
- David Galbraith
Every now and then, an idea comes along that makes just about everybody
smack their forehead and think "Hey, why didn't I think of
that?" Such was Thomas Huxley's response to reading Charles Darwin's
theory of natural selection for the first time - it was so simple - why
didn't I think of it? Just about everyone who is interested in ecology and
the marvelous and frightening interactions between people and the natural
environment have the same reaction when they first read a description of
the concept of the ecological footprint.
We live in a society in which physical distance from resource to
consumer has been largely obscured by an efficient global transportation
network. It's perfectly commonplace to walk into a store on any street
corner and buy fresh bananas or fresh oranges, staples of our daily diet
that a century ago were relative luxuries. As individuals we think nothing
of flying to Florida or Europe or even Australia for business or for
pleasure. We drive immense distances in complex cars, burning fossil fuels
and also making use of an immense network of paved and gravel roads.
Those of us who own property, mostly as our individual residential
lots, tend to have a very good idea of how big the property is, who our
neighbors are, and how we use the space within that property. Very few of
us however, earn our subsistence from the land that we own. By purchasing
goods and services that are dependent on land that is somewhere else, we
fulfill our daily needs without an awareness of how much land must be
dedicated to fulfilling those needs.
How much land do you need? How much space does it really take to
satisfy the consumers in all of us? After all, useable land it is a very
finite commodity. Over the centuries, some societies have successfully
increased their useable land through reclamation from wetlands, lakes or
the sea, or by extending agriculture and settlement into areas that would
be considered less than hospitable. For the most part however, useable
land is finite. Coming to an understanding of the demands we place on that
finite resource is an important component in understanding how we really
interact with the rest of the world.
An ecological footprint is an estimate of how much
ecologically-productive terrestrial space an activity uses or displaces.
The idea of an ecological footprint arose in the late 1980s through the
research of Matheis Wackernagel and William Rees in British Columbia.
Their insight was that it is possible to estimate the amount of land that
is needed to support an individual, or a community, in any society. By
estimating the area of the land, or the "footprint" of the
activities, and comparing that area among societies it is possible to
understand the relative impact of consumption and lifestyle.
If the footprint is not an actual area of land, then how is it
estimated? Wackernagel and Rees recognized that that there are two ways in
which the ecological footprint of a city, for example, could be
calculated. One could either add up all of the physical area of the city,
and then add in the amount of land required to support agriculture, waste
removal, construction, and all of the other services and materials that
the city would use, or one could tally up all of the activities and
consumption of an average individual and multiply that by the population
of the city.
These two approaches are clearly related to each other. If one knows
that the city has a population of a million, estimating the ecological
footprint for the entire city and then dividing the footprint by 1,000,000
provides an estimate of the ecological footprint of an average individual
in the city.
Wackernagel and Rees devised a detailed procedure for calculating
ecological footprints in the early 1990s. The calculations themselves are
complex because they must include many separate factors. In addition to
the obvious use of land for dwellings, transportation, provision of forest
products and other building materials, and arable land in agricultural
production, several other types of land use must be included. Land that is
dedicated to the production of fossil fuels for energy, land that is
consumed by the disposal of waste, and even land that is necessary for the
support of ecological services must be included in the calculation.
Ecological services are worth a special mention. These are all of the
many factors upon which our society depends that actually come from
natural ecological systems outside of the recognized human economy. Things
like the recycling of carbon dioxide and oxygen by natural forests, and
the provision of pollination by free-living insects, critical to our
agricultural production, are all ecological services. Estimates of the
value of ecological services to the whole human economy suggest that if we
had to replace these services through some kind of technological means,
the cost would exceed the total gross global value of the human economy by
a factor of about three.
So, how big did Wackernagel and Rees estimates our ecological footprint
to be? In 1995, the average Canadian was thought to have an ecological
footprint of approximately 4.3 hectares. In part, that figure was based on
annual carbon dioxide emissions of about 15.2 tonnes per year per person,
an annual purchasing power in US dollars of $19,320.00, an average of 46
vehicles per 100 persons, paper consumption of 247 kg of paper per year
per person, and the consumption of 250 gigajules of fossil energy use, and
consumption of 1,688 m³ of fresh water per year.
In contrast, the world average ecological footprint in 1995 was
estimated to be 1.8 hectares. Average global carbon dioxide emission was
less than 30% of the Canadian emission, and average world purchasing power
was $3,800.00 US dollars in 1995. Globally, there are about ten vehicles
for every 100 persons, average paper consumption is only 44 kilograms per
year per person, and average energy use is approximately 20% or 50
gigajules per year per person. Consumption of fresh water per person
averaged 644 m3 of water per year, approximately 1/3 of the
Canadian average.
At the other extreme, the ecological footprint of an average person in
India was approximately 0.4 hectares per person in 1995. That figure is
based on carbon dioxide emissions of 0.81 tonnes per year per person, an
average purchasing power $1,150 US dollars, an average of 0.2 vehicles per
100 persons, the consumption of two kilograms of paper per year, and five
gigajules of fossil fuel energy use. The average person in India consumes
612 m3 of fresh water per year.
The kinds of calculations that go into estimating ecological footprints
can be quite detailed. For example, researchers have estimated that on
average we continuously need 0.16 hectares of land to grow the trees to
produce the cellulose fiber that is necessary to support each Canadian's
consumption of newsprint alone.
It should be noted that a hectare is a measure of the area of land
within a square 100 m on each side. Thus, a hectare is 10,000 m², or
1/100 of a square kilometer. Each hectare is also about 2.7 acres. The
typical quarter-acre house lot is about a thousand square metres, or a
tenth of a hectare. This means that the consumption of newsprint by an
average household in Canada requires the dedication of more than 1 1/2
times the land area of most people's property just to the production of
the trees needed.
Of course, Canada is a big country. With a relatively small population,
the consumption of a proportionately large ecological footprint is less
worrying than if our population were much larger. The ecological footprint
of individuals in the United States is similar, on a per person basis, to
the ecological footprint of Canadians. In 1995, it was estimated that the
ecological footprint of an average American was 5.1 hectares. If we assume
an average ecological footprint of five hectares per person for people in
Canada and the USA combined, we can rapidly come up with an estimate of
total ecological footprint for the population of northern North America.
If the consuming population of Canada is 25,000,000 people, then the
ecological footprint of all Canadians is approximately 1.25 million square
kilometres. Using the same basic figure for consumption, the population of
the United States as an ecological footprint of approximately 12.5 million
square kilometres.
These numbers have two important implications. First, the consumption
of resources and the use of space by the affluent population of northern
North America represents an ecological footprint of close to 14 million
km². As the actual area of Canada is 9.9 million km2 and that
of the USA is 9.1 million km2, the combined ecological
footprint of our societies is close to 75% of the total available domestic
territory. In reality, of course, much of the territory of North America
is not available to the uses implied in the ecological footprint, and some
of the categories of consumption are based on the use of land elsewhere in
the world. Our affluent societies are clearly having a strong impact on
the land upon which they are based.
The second implication arises when the ecological footprint of our
society is compared to that of other consumers around the world. If
everyone on earth could have the same economic and material advantages
that we enjoy in Canada, the ecological footprint of that consumption
would require at least two entire extra planet earths to support. Clearly,
there are physical limits to the capacity of our planet to support an
affluent lifestyle.
Another thoughtful analogy arose out of the description of the
ecological footprint idea. If the available land on earth is finite, it is
possible to estimate the share of the surface of the planet that each
individual person would receive if all of the land were divided up person
by person. The 6,000,000,000 people on earth each would have their share
of the planet equal to a little less than 1.5 hectares, or a square a
little less than 120 m on a side. Of that 1.5 hectares, only about 0.25
hectares would be arable land. This theoretical portion of the surface of
the earth per person is called an individual's earthshare.
As our global population continues to rise, we are faced with important
challenges about our use of space and the effects of our activities on
such finite quantities as arable land. The valuable perspective that is
afforded by considering ecological footprints is essentially the
perspective of a society that is already providing for the material wants
of its citizens at a level that is unprecedented in human history. In
developing countries around the world, the aspirations of billions for a
better life for themselves and their children depend upon increasing their
consumption of resources and engaging in economic activity that
accumulates wealth. Does the comfortable perspective of Canadians,
repeatedly identified by the United Nations as the beneficiaries of the
most comfortable lifestyle on earth, have any positive message for
ourselves or for others?
Having spent a great deal of the last 20 years wrestling with this
issue, I am sure of only one thing: there are no simple answers. On the
one hand, it is a certainty that if the billions of people around the
world who aspire to a more comfortable life were suddenly granted access
to resources that we as Canadians take for granted, we would face
ecological ruin, followed shortly thereafter by economic ruin as the
natural systems upon which our economy depends grind to a halt. On the
other hand, it is perfectly possible to craft a lifestyle for oneself that
does not depend on 5 or more hectares of ecological footprint, but which
treads much more lightly on the earth. The experience of highly developed
societies in Europe, and available technologies for energy efficiency and
recycling, all indicate that it is possible to have a relatively small
ecological footprint and a relatively high standard of living.
For further reading&ldots;
The figures presented originally in this article in printed form are
from: Wackernagel, M. and Rees, W. 1996. Our Ecological Footprint;
Reducing Human Impact on the Earth,. New Society Publishers, Gabriola
Island, BC. 176 pages Illustrated. Canada Paperback ISBN 1-55092-251-3.
Several Internet Web sites allow visitors to calculate their own
individual ecological footprints. Here are just a few:
|
