Ecological Footprints

Oct0ber-November 1995

This is an article from WaveLength Magazine, available in print in North America and globally on the web.

Survival means we must step lightly on the Earth

by David Suzuki

The steep rise in human numbers andtechnology is having serious ecological repercussions that can't be stopped by merely tinkering with the social, economic, and political structures. We need to shift our priorities to find ways of living more lightly on the planet while ensuring that important human economic and social needs are not compromised. Popular articles by Bill Rees, a professor of urban planning at the University of British Columbia, and his associates confront us with stark faces that demand response.

In "Down to Earth: The Ecological Footprint", they define our real needs: "Human life depends on nature's resource production, waste sinks, and life-support services. Securing ecological stability is therefore a non-negotiable bottom line."

Rees uses a concept called the "ecological footprint" that measures "a community's demand on the global carrying capacity and compares this with nature's available long-term carrying capacity."

In "How Big is Our Ecological Footprint?", Rees' student, Mathis Wackernagel, examines human essentials provided by nature: "Energy is needed for heat and mobility, wood for housing and paper products, and we need quality food and clean water for healthy living... Green plants convert sunlight, carbon dioxide, nutrients, and water into plant matter, and all the food chains which support animal life -- including our own -- is based on this plant matter. Nature also absorbs our waste products, and provides life-support services such as climate stability and protection from ultraviolet radiation."

A task force on planning healthy and sustainable communities developed methods to measure human consumption in terms of units of land needed to supply those services. It defines ecological footprints as the "land that would be required on the planet to support our current lifestyle forever."

Wackernagel says: "The ecological footprint of an average Canadian adds up to over 4.8 hectares or an area comparable to three city blocks." That includes 1.3 hectares for food, 1.0 for housing, 1.1 for transport, and 1.1 for consumer goods. Looked at another way, land use involves 2.9 hectares for energy, 1.1 for farmland, 0.6 for forest, 0.2 under pavement and buildings.

Wackernagel calculates the ecological footprints of different kinds of households: a single parent with child has annual home expenditures of $16,000 and requires 3.1 hectares; a student living alone, $10,000 and 3.9 hectares; an average Canadian family (2.72 people), $37,000 and 4.8 hectares; a professional couple with no children, $79,000 and 13.5 hectares.

The ecologically productive land available to each person on Earth has decreased from five hectares in 1900 to 3.6 in 1950 and to 1.7 (0.3 arable) in 1990. Assuming no further soil degradation and current population growth, by 2030 it will decline to 0.9 hectares. Land appropriated by richer countries has increased from one hectare in 1900 to two in 1950 to between four and six in 1990. The shocking conclusion: If everyone on Earth lived like the average Canadian we'd need at least three Earth's to provide all the material and energy essentials we currently use.

"The Lower Fraser Valley, the area east of Vancouver, contains 1.7 million people or 4.25 people per hectare. If the average Canadian needs 4.8 hectares, then the Lower Fraser Valley needs an area 20 times what's actually available for food, forestry products, and energy... In other words, human settlements don't affect only the area where they're built."

Increasing concentrations of people in cities can be a benefit in terms of energy consumption for transportation and housing. The 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 how we do it. All of us 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 future generations."