What is an ecological footprint?

The ecological footprint is a sustainability indicator expressing the relationship between society's consumption of natural resources and the natural environment. Using area equivalence, it aims to express how much of nature's 'interest' we are currently appropriating. If more bioproductive land and sea is required than what is available, then it is possible to assume that the rate of consumption is not sustainable (Chambers et al., 2000). Alternatively, if everyone lived within their earthshare, we would consume only as much as the planet is able to provide.

As the ecological footprint analysis uses a common currency (global hectare), a broad range of impacts can be aggregated to derive ecological footprints for products, individuals, processes, organisation, regions and countries. It is a 'snapshot' measure and is based on a year-specific data set - 2001 for this study.

Figure 1
Area and sea types used to calculate an ecological footprint

fig 1

Comparing the resource flow and ecological footprint analysis

It is important to point out how the boundaries used for the Resource Flow Analysis (RFA) differ from the boundaries used for the Ecological Footprint Analysis (EFA). The RFA uses the geographic principle, i.e. it takes into account the flows of resources throughout the region. The EFA uses the responsibility principle, i.e. takes into account the resources consumed by residents of the South West. For example, the RFA would include consumption impacts of an airport, irrespective of where the airport users lived. The EFA only takes into account the share of the airport's impacts attributable to South West residents.

It is therefore important not to assume a direct correlation between data in the RFA and the results of the EFA.

Sustainable resource consumption and production

Ecological footprinting as the link between resource efficiency and sustainable consumption

'Sustainable' production

The ecological footprint is proving to be a compelling indicator of sustainable consumption. It has two key features that make it so powerful:

  • It aggregates consumption of a wide range of resources (both energy and materials).
  • It can be used to compare resource consumption (the ecological footprint) with globally available resources (the earthshare) to illustrate what level of consumption is sustainable.

Can ecological footprinting also be an indicator of 'sustainable' production?

The ecological footprint can effectively be used to aggregate the impact of resources consumed in the production process to provide a resource efficiencymetric per unit of production. It is possible to compare the ecological footprint of 'product A' with 'product B' or with the per person average earthshare. It is also possible to show how much of the ecological footprint per person is attributable to the consumption of 'product A'. But, while a company or product may be increasingly eco-efficient, no single product or company can, in itself, be sustainable.

Sustainability is a function of

  • Impacts from all activities of all populations
  • Impacts throughout the lifecycle
  • Comparison of all those impacts with available resources.

All of these factors must be taken into account when analysing sustainability. So, the ecological footprint can be a useful resource efficiency metric, but sustainability does not apply to production, only to consumption.

Resource efficiency

Can ecological footprinting be used to indicate the most resource efficient way of manufacturing a product?

By including a wide range of energy and material resources, ecological footprinting can be used to compare the aggregate resource efficiency of producing similar products. Perhaps two comparable nappies use differing amounts of wood fibre and plastics. Ecological footprinting can indicate which one, overall, is the most resource efficient. This can be useful in identifying and encouraging best practice in resource efficiency, or in responsible procurement processes. This should be of interest to policy makers and business support programmes at the regional, national and global levels.

Can ecological footprinting be used to indicate the most resource efficient way of providing a service?

By accounting impacts throughout the lifecycle (in production and use) and normalising them to 'service units', ecological footprinting can indicate the most resource efficient way of providing a service, for example, travel by car. Ecological footprinting can be applied to the manufacture of the car providing the travel services.

The direct energy used to build a Honda, in Swindon in 2001, had an ecological footprint of 0.17 gha*, but the footprint of the energy consumed in manufacture was about 6% of that throughout the lifecycle of the car, assuming average South West use. The ecological footprint per vehicle-kilometre is dependent on both manufacture and use efficiency.

Can ecological footprinting be used to indicate the most resource efficient way of creating economic wealth?

Ecological footprinting can be used alongside economic indicators such as GDP or GVA, to estimate the most resource efficient way of generating economic wealth. For example, the tourism industry in the South West has an annual ecological footprint of 2,036,375 gha and generates £2,439 million of GVA. (£1,198/gha). The motor manufacturing plant run by Honda in the South West has an estimated ecological footprint of 296,101 gha, and generated an estimated £160 million of GVA (about £542/gha).

This is of interest to economic development agencies charged with encouraging industries with low resource intensities within their economic base. However, it should be noted that if society consumes products and services with higher resource intensities, these must be manufactured somewhere. There is always the possibility that although a population sources low intensity products from the domestic economy, it will source high intensity products from elsewhere – the impacts are still incurred, but have been exported – a process sometimes referred to as 'burden shifting'. As sustainability is a global property, this approach will not improve the sustainability of the population.

Can ecological footprinting be used to assess whether a product or service, business or sector is 'sustainable'?

A product or service cannot be defined as 'sustainable' in itself, but the ecological footprint can be used to indicate whether the resource efficiency of a product or company is improving or declining. Ecological footprinting can also determine the contribution of a product or service to sustainable resource consumption. For example, services provided by the NHS in England and Wales consumed 2% of the total ecological footprint per person in 2001, and 5% of the average earthshare. Clearly it is necessary to apply ecological footprinting across all activities to enable this comparison.

* Calculated based on data from Honda's Safety & Environment Report (Honda, 2001).