William Rees and Mathis Wackernagel

Rees and Mathis Wackernagel
Contemporary 20th Century

Canadian Professors and Sustainability Advocates, Mathis Wackernagel, under William Rees' supervision developed Ph.D. Dissertation on the Ecological Footprint, establishing human demand on the Earth's Ecosystems

Author Quotes

Imagine that nature is a bucket that is continuously replenished by the sun, photosynthesis produces plant matter, the basis of all biological capital and most other life; and climate, hydrological and other biophysical cycles are solar powered too. The water in the bucket is capital stock that can be drawn on only as rapidly as the bucket is being refilled. This balanced withdrawal rate is a form of sustainable income... Unfortunately, even today's levels of appropriation are unsustainable.

EFA certainly remains an imperfect tool. However, its major weakness may be the inherent conservatism of the method rather than the concerns expressed by economists and techno-optimists. EFA findings, already alarming enough, likely under-estimate rather than over-estimate the total human load. In this light the real sustainability problem is that the official world remains in the thrall of the perpetual growth myth.

People are intelligent beings capable of responding rationally to new knowledge particularly if it can be shown to be directly relevant to their own circumstances. For this reason, the eco-footprint concept resonates better with the public than do more abstract and impersonal sustainability indicators. In particular, people appreciate the way EFA draws them into reflecting on their personal consumption habits as illustrated by the popularity of EFA-oriented web-sites that offer simple calculators that visitors can use to estimate their personal eco-footprints. Attributes of EFA that help to communicate biophysical reality to the public include the following:
The method is conceptually simple and intuitively appealing. Even sceptics recognize that that they have a positive ecological footprint.
EFA personalizes sustainability by focusing on consumption—everyone is a consumer and must ultimately take responsibility for his/her own ‘load’ on the planet.
EFA consolidates measurable energy and material flows into a single concrete variable, the corresponding appropriated land/water (ecosystem) area.
Land itself is a powerful indicator. Everyone understands ‘land.’ (Popular understanding of the ecological crisis is prerequisite to any politically viable solutions.)
Eco-footprint estimates can be compared to finite local and global ‘supplies’ of terrestrial and aquatic ecosystems (i.e., people and populations can compare their demands to available bio-capacity).
The ‘ecological deficit’—the difference between domestic bio-capacity and a larger eco-footprint—requires little explanation and many people see it as more important than the fiscal deficits with which their governments are often preoccupied!
EFA appeals to both the ecologically and socially conscious. For example, it reflects gross material inequity but also shows that growth is not a sustainable option to relieve it.
Perhaps as important as any other factor, ‘ecological footprint’ is a powerfully evocative metaphor—would people be as quickly captivated by the concept had it been called the ‘human impact index’ instead?

Ecological footprint analysis has gained considerable momentum around the world as both heuristic device and practical method for assessing sustainability. This success derives in part from methodological strengths of EFA that are both scientifically well founded and reflect thinking people’s intuitive sense of reality. On the technical/scientific side, EFA has several qualities that reinforce its credibility as a sustainability indicator. The method:
acknowledges that humans are biophysical entities that make constant metabolic demands on their supportive ecosystems and that all our manufactured capital and related cultural artefacts impose a parallel and much larger industrial metabolism on the ecosphere;
recognizes the crucial role of natural capital and natural income (biophysical stocks and flows) in economic development and sustainability;
accepts that the economy is a fully contained, growing, dependent, sub-system of the non-growing ecosphere;
recognizes the second law of thermodynamics as the ultimate governor of material transformations and economic activity (Georgescu-Roegen 1971, Daly 1991) and that beyond a certain (optimal) scale, the growth and maintenance human enterprise must necessarily accelerate the entropic disordering and dissipation of the ecosphere;
is closely related conceptually to Odum’s the embodied energy (emergy) analyses (see Hall 1995) and the ‘environmental space’ concept of the Sustainable Europe Campaign (Carley and Spapens 1998).
accounts for both population size and resource consumption in estimating of appropriated ecosystem area. This aligns EFA closely with Catton’s (1980) concept of human ‘load’ (population times per capita consumption);
corresponds closely to and incorporates all the factors in Ehrlich’s and Holdren’s (1971) well-known definition of human impact on the environment: I = PAT, where ‘I’ is impact, ‘P’ is population, ‘A’ is affluence (i.e., level of consumption) and ‘T’ is a technology scalar.

Population eco-footprints are based on final demand for goods and services. Thus, the first step in calculating the ecological footprint of a study population is to estimate the total annualized consumption of significant categories of commodities and consumer goods consumed by that population. Data are obtained from national production and trade statistics and other sources such as various United Nations statistical publications. For accuracy, consumption data should be trade-corrected. Thus the population’s consumption of pulses (beans, peas and lentils) can be represented as follows:
consumptionpulses = production pulses + imports pulses - exports pulses

The area of a population’s theoretical eco-footprint depends on four factors: the population size, the average material standard of living, the average productivity of land/water ecosystems, and the efficiency of resource harvesting, processing, and use. Regardless of the relative importance of these factors and how they interact, every population has an ecological footprint and the productive land and water captured by EFA represents much of the ‘natural capital’ (productive natural resource base) required to meet that study population’s consumptive demands.
It is important to recognize that population eco-footprints constitute mutually exclusive appropriations of productive capacity. The biocapacity used by one population is not available for use by another. All human populations are competing for the available productive capacity of Earth.

EFA [Ecological Footprint Analysis] starts from a series of simple premises:
Human beings are integral components of the ecosystems that sustain us. We can therefore best assess ecological sustainability using biophysical data.
Most human impacts on ecosystems are associated with energy and material extraction and consumption.
These energy and material flows can be converted to corresponding productive or assimilative ecosystems areas.
There is a measurable, finite area of productive land and water ecosystems on Earth.
Every human population imposes an ‘ecological footprint’ on Earth equivalent to the amount of the planet’s productive capacity required to supply that population with resources and waste assimilation services. We therefore formally define the ecological footprint of a specified population as the area of land and water ecosystems required on a continuous basis to produce the resources that the population consumes, and to assimilate (some of) the wastes that the population produces, wherever on Earth the relevant land/water may be located.

Ecological footprint analysis (EFA) was introduced explicitly to reopen the debate on human carrying capacity (Rees 1992, 1996; Rees and Wackernagel 1994, Wackernagel and Rees 1996). Indeed, the method gains much of its analytic strength by inverting the standard carrying capacity ratio. If carrying capacity asks ‘how large a population can a particular area support’ (a question that can be rendered seemingly irrelevant by trade) EFA asks ‘how large an area is required to support a particular population’ (a question that includes those areas that are effectively ‘imported’ through trade). Answering this second question enables any population to compare its total biophysical demand on Earth to the biocapacity of its domestic land-base, thus revealing the extent to which that population is living beyond its local ecological means. EFA also allows the population to assess the proposition that its consumption patterns are ‘decoupling’ from nature—i.e., a sequential time series of EFAs will reveal whether the population’s lifestyles are really becoming less material-intensive and more ecological benign.

Despite the cascade of empirical evidence that even the present scale human economic activity threatens to undermine the integrity of the ecosphere, there is little evidence in the international policy arena that mainstream institutions are seriously willing to consider abandoning perpetual growth machine. Indeed, policy makers generally believe that the Malthusian dilemma and concerns about ‘limits to growth’ have long been put to rest.

It is no small irony that in the age of ‘technological man’ people actually play a greater role in ecosystems than ever. For example, H. sapiens has long been the most successful terrestrial carnivore ever to have walked the earth and, during the 20th Century, humans became the most voracious predator in the world’s oceans. Remarkably, considering our unchallenged status as top carnivore, we are also the dominant herbivore in grasslands and forests all over the planet, particularly if we consider the demands of ‘industrial metabolism’ (Rees 2003a, Fowler and Hobbs 2003). And human impacts transcend biology, earth scientists assert that economic activity has become the most significant geological force altering the face of the planet and climatologists agree that we are now actually beginning to affect global climate.

The Earth's biophysical systems are large, complex, self-organizing entities. This means there is typically a long lag time between economic cause and ecological effect. (For example, whatever global warming we may already have experienced is not the result of today's levels of greenhouse gases but rather the levels reached perhaps 40 years ago; even though CFC production may be winding down, ozone depletion may worsen for a decade and it may be a half century or more before stratospheric ozone returns to normal.) Thus, the temptation to wait until we are certain that a particular trend is fatal, dangerous or simply uneconomic before deciding on corrective action leads us into an ecological trap. At best, the delay simply further entrenches our unsustainable lifestyles, making change the more difficult; at worst, it will be too late to do anything to reverse the trend.

The fact is that consumption is limited by nature's reproductive capacity--over-consumption today means less natural capital and lower natural income tomorrow. This, in turn, may force future generations to accelerate the downward spiral as they erode remaining stocks of natural capital to meet their own consumption needs. In other words, life on Earth (including human life) can be sustained only within the limits of the dividends nature pays on our remaining stocks and future investments in natural capital. ...sustainability requires that the human enterprise remain within global carrying capacity.

Pain is not an evolutionary error.

The two-word definition of sustainability is 'one planet.

Growth is a pressing moral imperative for those whose needs are not being met, and industrialized countries have not yet found ways to maintain their standard of living, without continued economic growth. One hopeful strategy to deal with this dilemma involves massive improvements in the efficiency of economic activity so that growth in consumption of goods and services is "decoupled" from growth in the use of energy and material. In theory, this should permit an increase in consumption to be accompanied by a decrease in resource use. In fact, this "dematerialization" of economic goods and services must proceed faster than economic growth to produce the necessary reduction in humanity's total load on the ecosphere. The political attractiveness of this approach is self-evident - it enables the rich to maintain their high material standards while freeing up the ecological space needed for the poor to increase theirs.

The present Ecological Footprint of a typical North American (4-5 ha) represents three times his/her fair share of the Earth's bounty. Indeed, if everyone on Earth lived like the average Canadian or American, we would need at least three such planets to live sustainably.

Ecological Footprint is the land (and water) area that would be required to support a defined human population and material standard indefinitely.

By the time a baby born today in the U.S. reaches age 75, (s)he will have used on average: 4,000 barrels of oil, 54,000 pounds of plant matter, 64,000 pounds of animal products, and 43 million gallons of water – and will have produced over 3 million pounds of liquid wastes and 1,500 tons of solid wastes.

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Rees and Mathis Wackernagel
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Contemporary 20th Century

Canadian Professors and Sustainability Advocates, Mathis Wackernagel, under William Rees' supervision developed Ph.D. Dissertation on the Ecological Footprint, establishing human demand on the Earth's Ecosystems