The ecological footprint is calculated by national and regional governments, private environmental organizations, and the media. To calculate the ecological footprint, each country or region is required to calculate the demand side (consumption of goods) and the supply side (land use). The demand side (comprising production, investments, and other non-renewable resource use) is determined using data on population, income per person, and food consumption.
How the Footprint Works
The ecological footprint is calculated by measuring the amount of biologically productive land and water required to produce the resources a population uses and absorb its waste using prevailing technology. It does not measure the amount of land needed to produce goods for export. It also does not consider carbon sequestration, so even if a forest, for example, is planted, it will still show as an ecological footprint unless that system has been accounted for in all previous calculations.
While the ecological footprint is often presented as an absolute measure, it should not be confused with an absolute definition of sustainability. The footprint is a relative concept. According to the ecological footprint website: A negative value indicates that a region has more ecological resources than it needs and thus that its consumption is lower than its ability to renew. A positive value indicates that a region uses more ecological resources than are available in its environment.
A Measure of Sustainability
The footprint is not a measure of absolute sustainability. It measures the resources needed to sustain our current consumption levels. This can be interpreted in two ways:
First, it means that any nation whose footprint is at or near zero (e.g., Haiti, Bolivia) has passed the point of sustainability. Its consumption patterns are already over-consuming Earth’s renewably-generated resources.
Second, it means that any nation with a positive Footprint (e.g., the USA, Japan) still has the same or more resources than is required to sustain its current consumption levels. Since these nations have a positive Footprint, we can infer that the use of resources is sustainable at the current level of consumption.
Because it is a relative measure, an increasing ecological footprint does not necessarily mean that a country is becoming less sustainable. For example, a country whose ecological footprint increases from 0 to 1 would be relatively more resource-rich but could still be sustainable from an absolute perspective. The broader impact of the ecological footprint is to provide a new metric for evaluating the sustainability of human activities. In theory, a larger Footprint is better than a smaller one. For example, it may indicate that a country has more resources available to support its population than it is using. In practice, however, the ecological footprint may not be useful as a measure of absolute sustainability because there are some unaccounted factors.
To date, there have been several criticisms of the ecological footprint. For example, the global ecological footprint may be a better metric of world sustainability than national Footprints, but it is still not an absolute measure. For one thing, the current consumption level is generally based on a threshold of basic human needs and wastes. This means that so-called “waste” is already being absorbed by renewable resources such as forests and oceans.
The other limitation of the ecological footprint is that it is theoretically impossible to address all factors. In practice, this means that some factors, such as carbon emissions, non-renewable resource extraction, and human health, may not be included in the Footprint calculation. These unaccounted factors can affect the accuracy of the measurement and, therefore, the results of an analysis.
The ecological footprint is not intended to compare the sustainability of human activities or nations. The calculation does not take into account the following:
Which uses of land and water are more worthy than others. For example, tourism may provide jobs for local people, but it could also damage traditional ways of life. How “good” a resource is depends on who consumes it and how they might use it differently if they had more opportunities or incentives. For example, a tourist could choose to eat locally grown food or eat some of that food and use the rest as landfill feedstock to dispose of.
Whether a resource is renewable or non-renewable. For example, the ecological footprint does not consider the carbon-sequestration potential of forests. Whether a resource is essential for human health and well-being (think about water) versus optional (think about fossil fuels). The environmental, social, and economic impact of resource extraction. For example, farm fish are counted as renewable resources, even though the fish farming industry has been shown to use more energy than it creates and is a cause of pollution and disease in the areas where it operates.
The ecological footprint is not a guide to choosing between resource-efficient technologies or activities. It simply measures their total impact on the planet.