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Input-Output Conference 2010

A detailed view of the Ecological Footprint

At the University of Sydney, we calculate comprehensive Ecological Footprints for organisations such as companies, government agencies and NGOs, or for cities, states and nations, and we can decompose the each footprint into a number breakdowns of high detail, which are then used for regional and corporate sustainability planning.

In the following, we present these breakdowns for the example of Sydney Water Corporation, at the macro-, meso-, and micro-level of detail.

All results are published in detail in the Journal of Environmental Planning and Management 46 (1), 113-141, 2003. You can also download a short, non-technical article about this work.

The Macro-level: Commodity / itemised breakdown:

The table below shows Sydney Water's Ecological Footprint and land / emissions components broken down for each purchased input of Sydney Water, and ranked by importance. This itemised breakdown allows Sydney Water to identify the purchased inputs that carry most of the organisation's impact, and that hence would attract attention when deciding on abatement measures.

The Meso-level: Production layer decomposition

The figure below shows a breakdown of the land disturbance component of Sydney Water's Ecological Footprint by production layer. A production layer is a level of suppliers into an organisation (for example a company). The horizontal axis of the diagram below shows these production layers. 0 is the company itself, 1 are the direct suppliers, 2 are the suppliers of the suppliers, and so on, covering the supply chain in an upstream direction. The vertical axis shows the land disturbance (in '000 hectares) associated with these production layers. The result is shown for each production layer, that is zeroth order is on-site land disturbance, 1st order is land disturbance caused by suppliers to Sydney Water, second order is the land disturbance of the suppliers of the suppliers, and so on.

The production layer breakdown shown in the graph "unravels" the commodity breakdown into the respective contributions from upstream layers.

Significant impacts and associated financial risks occur in higher orders of production a comprehensive assessment of the impact of a company is usually not complete until 7th to 10th-order impacts are enumerated. These higher orders are not looked at in conventional Ecological Footprints. A production layer diagram gives insights about how "deep" the footprint impact of an organisation reaches into the economic system.

The Micro-level: Structural Path Analysis

The list below shows a Structural Path Analysis for Sydney Waters Ecological Footprint (top 12 paths shown). This Structural Path Analysis "unravels" the production layer decomposition into single contributing supply paths. Such an analysis can be carried out for any entity, be it nation, state, region, city, council, company, household, or individual.

The Structural Path Analysis hence gives extensive detail of the impact of an organisations activities. It allows indentifying the location of impacts within the economic system, and as a result the possibility of substitution of suppliers to more sustainable suppliers.

In the example above, rank 1 represents emissions from power plants supplying Sydney Water with electricity. Rank 2 are Sydney Water's own emissions, that is methane from their water treatment plants. Rank 3 are emissions from Sydney Water's car fleet. Rank 4 is Sydney Water's own land, and the disturbance caused by pumping stations etc. Rank 5 are emissions occurring during the production in the chemical industries of chemicals that Sydney Water uses. Rank 7 are emissions from steel plants that produce structural steel elements that are used by contractors that undertake Sydney Water's construction works. Rank 8 are seam gases (mostly methane) that emerge from coal seams in mines that supply power plants that supply Sydney Water with electricity. Rank 9 is land disturbed by overhead lines or hydro reservoirs for electricity consumed by Sydney Water. Rank 12 are emissions from planes carrying Sydney Water personnel to meetings etc. Thousands of paths that are often up to 5th or 6th order can be identified using this technique.

For further information please contact

Dr Arne Geschke
ISA, School of Physics A28
The University of Sydney NSW 2006
+61 (0)2 9036-7505