Making our mark – ecological footprints
Glossary
biocapacity (biological capacity). The capacity of an area or ecosystem to generate an ongoing supply of resources and to absorb its wastes. Unsustainability occurs if the ecological footprint (demand on the system) exceeds biocapacity.
The biocapacity of an ecosystem is calculated by taking into account its area, land type and productivity. Biocapacity is usually expressed in units of global hectares.
biomass. Plant or animal matter (including agricultural waste) used as a fuel or energy source. Alternatively, the total mass of living matter within a given environmental area.
biosphere. The region of Earth and its atmosphere that is inhabited by living organisms.
carbon-neutral. A state whereby emissions of carbon-containing gases are balanced by the amount being stored; for example, balancing carbon dioxide emissions by growing plants which take in carbon dioxide.
carbon offset. An investment in an activity that reduces greenhouse gas emissions or removes them from the atmosphere. Carbon offsets are used to compensate for greenhouse gas emissions from your own activities.
carbon trading. The trading of greenhouse gas emission rights. Participants in carbon trading buy and sell certificates that represent specified amounts of emissions or credits for reductions in emissions. Placing a cost on carbon emissions encourages organisations to reduce them eg. through renewable energy, improved energy efficiency or carbon offsets.
ecological footprint. The amount of biologically productive land and water that is needed to supply resources and absorb wastes. Ecological footprints are usually expressed in units of global hectares.
global hectares (gha). Unit for measuring our demands on the Earth (ecological footprint) and the ability of the Earth to supply our demands (biocapacity). A global hectare is one hectare of land or water with world-average productivity. Measurements in global hectares are adjusted according to the productivity of land or water in a given year. A land type of high productivity (eg. cropland) will have more global hectares than less productive land (eg. pasture) of an equivalent size.
greenhouse gas. A gas that is transparent to incoming solar radiation and absorbs some of the longer wavelength infrared radiation (heat) that the Earth radiates back. The result is that some of the heat given off by the planet accumulates, making the surface and the lower atmosphere warmer. For more information see The greenhouse effect (CSIRO Atmospheric Research, Australia).
Life Cycle Assessment (LCA). An assessment of the impact of a product on the environment throughout its life. Measures what is needed during production and what is produced from 'cradle to grave'. This includes energy and materials used for obtaining the raw materials for the product, product manufacture and assembly, transport of the product, its use and disposal. Wastes produced during the product's life are also accounted for.
unsustainable. Use of resources at a rate that will eventually deplete the resources and/or cause major ecological damage. An activity that uses natural resources at a rate above the natural rate of their replacement.
Posted December 2008.