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How Big is Our Ecological Footprint?
Using the Concept of Appropriated Carrying Capacity for Measuring Sustainability
Mathias Wackernagel with The Task Force on Planning Healthy & Sustainable Communities, The University of British Columbia

People depend on nature, which provides a steady supply of the basic requirements for life. Energy is needed for heat and mobility, wood for housing and paper products, and we need quality, food and clean water for healthy living. Through a process called "photosynthesis" green plants convert sunlight, carbon dioxide, nutrients and water into plantmatter, and all the food chains which support animal life - including our own - are based on this plant 'matter. Nature also absorbs our waste products, and provides life-support services such as prove climate stability and protection from ultra-violet radiation. Further, nature is a source of joy and inspiration. Figure I shows how very tightly human life is interwoven with nature, a connection we often forget or ignore. Since most of us spend our lives in cities and consume goods from all over the world, we tend to view nature as a collection of commodities or a place for recreation, rather than the very source of our existence.

Figure 2

If we're to continue to have good living conditions, we must ensure that nature's productivity isn't used more quickly than it can be renewed, and that waste isn't discharged more quickly than nature can absorb it. We know from the increasing loss of forests, soil erosion and contamination, fishery depletion, loss of species and the accumulation o f greenhouse gases that our current overuse of nature is compromising our future well-being.

To find out whether nature provides enough "resources" to secure good living conditions for everyone in a community, the Task Force on Planning Healthy and Sustainable Communities at , the University of British, Columbia has developed an ecological accounting tool that uses land area as its measurement unit. Various categories of human consumption are translated into the areas of productive land

Our current economy has given rise to increasing demands which compete for dwindling supplies of life's basic necessities such as food, clean water, etc. A group's ecological footprint can be used to measure its current consumption against projected requirements and point out likely shortfalls. In this way society as a whole can compare the choices we need to make in the near future about our demands on nature - or else nature will make our choices for us. We'll have to look at issues like long term ecological sustainability as they relate to future economic health.

Table I shows the ecological footprint of an average Canadian, i.e. the amount of land required from nature to support each individual's present consumption. This adds up to over 4.8 hectares, or an area 220 metres long by 220 metres wide roughly comparable to three city blocks. The column on the left shows various consumption categories, and the headings across the top show land use categories.

"Energy" as used in the table means how much land would be necessary for the long term provision of a biological substitute for fossil fuels (coal, oil and natural gas). "Built Environment" means land that's no longer available for nature's production because it's been paved over or used. for building. Examples of what's included in "Resources in Services" are the fuel needed to heat, a hospital, or the paper and electricity used to produce a bank statement.

To use the table to find out how much agricultural land is required to produce the average Canadian's food for instance, you'd read, across the "Food" row to the "Agricultural Land" column, and find that 0.9 hectares of land is needed.

The ecologically productive land available to each person on Earth has decreased over the last century (figure 4). At the moment there is, on average, 1.6 hectares (about one city block), or one-third of the area which each Canadian is currently using according to table 1. In contrast, the land appropriated by richer countries has increased.

Figure 4: A historical look at the ecologically productive land available to each person and our ecological footprints

This means that if everyone on Earth lived like the average Canadian, we'd need at least three Earths to provide all the material and energy essentials we currently use (figure 5).

If the' world's population continues to grow as anticipated, by the year 2030 there will be 10 billion people, each of whom will have an average of only 0.9 hectares of productive land available, assuming there's no further soil degradation. This shows th e pressure of population size on nature's productivity.

The numbers become really interesting when you look- at the land area that people in North America actually use. Figure 6 shows the ecological footprint for the Lower Fraser Valley, the area east of Vancouver, which contains 1.7 million people or 4.25 people per hectare. The area is far smaller than that needed to supply the resources for. its population. If the average Canadian needs 4.8 hectares as shown in table 1, then the Lower Fraser Valley needs an area 20 times larger than what's actuall y available for food, forestry products and energy.

Holland has a population of 15 million people or 4.40 people per hectare, and although Dutch people consume less than Canadians on average, they still require more- than 15 times the available land for food, forest products and energy. In other words, hu man settlements don't affect only the area where they're built.

Increasing density in cities can lead to lower land use requirements, not only because of a reduction in the built environment, but -also because of lifestyles which are less energy-intensive. For example, a recent study of the San Francisco area found t hat when residential density was doubled, private transportation was reduced by 20 to 30 percent. It's also been shown that residential heating requirements can be reduced significantly if housing is grouped rather than free-standing.

Our challenge is to find a way to balance human consumption and nature's limited productivity in order to ensure that our communities are sustainable locally,, regionally and globally. We don't have a choice about whether to do this, but we can choose ho w we do it. In fact, many people concerned with these issues believe that if we choose wisely now, there's still time for us to make our communities more sustainable, and at the same time improve our quality of life.

There are three key requirements for developing a sustainable community

(a) Ecological health. Use nature's productivity without damaging it.
(b) Community health. Foster social well-being-through the promotion of fairness, equity and cooperation.
(c) Individual health. Secure food, shelter, health care, education etc. for everyone.

This means working to integrate environmental, economic and social policies so that economic success, ecological integrity and social health become compatible.

In order to make our communities more livable and sustainable we can work towards change at the personal, urban and commercial levels.

Households can start by reducing their resource consumption. At the urban level we must develop an infrastructure that leaves. options open, rather than one which dictates resource-intensive lifestyles for our own and future generations. Along. with the se lifestyle changes, there must be changes in our economies.

This approach differs from today's global economy which .favours urban industrial centres, and requires the support and involvement of people in each sector of society.

We can all make a difference. Influential groups are:

Politicians (MPs, MLAs, City Councillors, etc), who can initiate or support sustainability programs and projects, particularly at the infrastructure level. They can set up screening processes which will take ecological impact into account whe n assessing a budget or project, and they can encourage the use of the concept of. sustainability by the government. They can persuade their parties to develop sustainability strategies, involve the public, and discuss the dilemmas being faced. They can support community groups working towards sustainable societies.

Administrators and planners, who can help politicians write, appropriate legislation and ensure that existing policies are followed. They too can involve the public, present them with the dilemmas and invite input. They can encourage people to participate in shaping the future of their community, and support and assist community groups making positive contributions to society.

The general public, which is all of us - possibly the most important group! We can look at our life styles, think about what's important to us and start family and friends thinking too. Let's get involved and participate in community and mu nicipal groups. Write and talk to politicians at a local, regional or national level, and let them know we want to work with them to develop our communities sustainably.

All of us including politicians and planners are consumers of nature's productivity. We must work together to achieve a more sustainable way of living now in order to ensure that resources continue to be available not only for ourselves, but also for fut ure generations.

For further information, please contact:

Janette McIntosh, Coordinator
The Task Force on Planning Healthy and Sustainable Communities
The University of British Columbia
Department of Family Practice
5804 Fairview Avenue
Vancouver, BC Canada V6T IZ3
phone-. (604) 822-4366, fax: (604) 822-6950

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