Glossary of Environmental Science - E

E

• eco- - a prefix now added to many words indicating a general consideration for the environment e.g. ecohousing, ecolabel, ecomaterial.
• eco-asset – a biological asset that provides financial value to private land owners when they are maintained in or restored to their natural state.
• ecolabel - seal or logo indicating a product has met a certain environmental or social standards.
• ecological deficit - of a country or region measures the amount by which its Ecological Footprint exceeds the ecological capacity of that region.
• Ecological Footprint (Eco-footprint, Footprint)– a measure of the area of biologically productive land and water needed to produce the resources and absorb the wastes of a population using the prevailing technology and resource management schemes; a measure of the consumption of renewable natural resources by a human population, be it that of a country, a region or the whole world given as the total area of productive land or sea required to produce all the crops, meat, seafood, wood and fibre it consumes, to sustain its energy consumption and to give space for its infrastructure.
• ecological niche - the habitat of a species or population within its ecosystem.
• ecological succession - the more-or-less predictable and orderly changes in the composition or structure of an ecological community with time.
• ecological sustainability - the capacity of ecosystems to maintain their essential processes and function and to retain their biological diversity without impoverishment.
• ecologically sustainable development - using, conserving and enhancing the human community's resources so that ecological processes, on which all life depends, can be maintained and enriched into the future.
• ecology - the scientific study of living organisms and their relationships to one another and their environment; the scientific study of the processes regulating the distribution and abundance of organisms; the study of the design of ecosystem structure and function.
• externality – a cost or benefit that are not borne by the producer or supplier of a good or service. In many environmental situations environmental deterioration may be caused by a few while the cost is borne by the community; examples would include overfishing, pollution (e.g. production of greenhouse emissions that are not compensated for in any way by taxes etc.), the environmental cost of land-clearing etc.
• ecoregion - (bioregion) the next smallest ecologically and geographically defined area beneath "realm" or "ecozone".
• ecosystem boundary – the spatial delimitation of an ecosystem usually based on discontinuities of organisms and the physical environment.
• ecosystem services - the role played by organisms, without charge, in creating a healthy environment for human beings, from production of oxygen to soil formation, maintenance of water quality and much more. These services are now generally divided into four groups, supporting, provisioning, regulating and cultural.
• ecosystem - a dynamic complex of plant, animal and microorganism communities and their non-living environment all interacting as a functional unit.
• e-cycling – recycling electronic waste.
• effective rainfall – the volume of rainfall passing into the soil; that part of rainfall available for plant use after runoff, leaching, evaporation and foliage interception.
• energy efficiency - using less energy to provide the same level of energy service.
• effluent - a discharge or emission of liquid, gas or other waste product.
• El Niño - a warm water current which periodically flows southwards along the coast of Ecuador and Peru in South America, replacing the usually cold northwards flowing current; occurs once every five to seven years, usually during the Christmas season (the name refers to the Christ child); the opposite phase of an El Niño is called a La Niña.
• embodied energy - the energy expended over the entire life cycle of a good or service cf. emergy.
• emergent property – a property that is not evident in the individual components of an object or system.
• emergy – “energy memory” all the available energy that was used in the work of making a product directly and indirectly, expressed in units of one type of available energy (work previously done to provide a product or service); the energy of one type required to make energy of another.
• emission standard - a level of emissions that, under law, may not be exceeded.
• emissions intensity – emissions expressed as quantity per monetary unit.
• emissions trading – see carbon trading.
• emissions - substances such as gases or particles discharged into the atmosphere as a result of natural processes of human activities, including those from chimneys, elevated point sources, and tailpipes of motor vehicles.
• endangered species – a species which is at risk of becoming extinct because it is either few in number, or threatened by changing environmental or predation parameters.
• energetics – the study of how energy flows within an ecosystem: the routes it takes, rates of flow, where it is stored and how it is used.
• energy - a property of all systems which can be turned into heat and measured in heat units.

* available energy – energy with the potential to do work (exergy);

* delivered energy – energy delivered to and used by a household, usually gas and electricity;

* direct energy - the energy being currently used, used mostly at home (delivered energy) and for fuels used mainly for transport;

* embodied energy - t the energy expended over the entire life cycle of a good or service OR the energy involved in the extraction of basic materials, processing/manufacture, transport and disposal of a product OR the energy required to provide a good or service;

* geothermal energy – heat emitted from within the Earth’s crust as hot water or steam and used to generate electricity after transformation;

* hydro energy – potential and kinetic energy of water used to generate electricity;

* indirect energy – the energy generated in, and accounted for, by the wider economy as a consequence of an agent’s actions or demands;

* kinetic energy - the energy possessed by a body because of its motion;

* nuclear energy - energy released by reactions within atomic nuclei, as in nuclear fission or fusion (also called atomic energy);

* operational energy – the energy used in carrying out a particular operation;

* potential energy – the energy possessed by a body as a result of its position or condition e.g. coiled springs and charged batteries have potential energy;

* primary energy – forms of energy obtained directly from nature, the energy in raw fuels(electricity from the grid is not primary energy), used mostly in energy statistics when compiling energy balances;

* solar energy – solar radiation used for hot water production and electricity generation (does not include passive solar energy to heat and cool buildings etc.);

* secondary energy – primary energies are transformed in energy conversion processes to more convenient secondary forms such as electrical energy and cleaner fuels;

* stationary energy – that energy that is other than transport fuels and fugitive emissions, used mostly for production of electricity but also for manufacturing and processing and in agriculture, fisheries etc.;

* tidal/ocean/wave energy– mechanical energy from water movement used to generate electricity;

* useful energy – available energy used to increase system production and efficiency;

* wind energy – kinetic energy of wind used for electricity generation using turbines

• energy accounting – measuring value by the energy input required for a good or service. A form of accounting that builds in a measure of our impact on nature (rather than being restricted to human-based items).
• energy audit - a systematic gathering and analysis of energy use information that can be used to determine energy efficiency improvements. The Australian and New Zealand Standard AS/NZS 3598:2000 Energy Audits defines three levels of audit.
• Energy Footprint - the area required to provide or absorb the waste from coal, oil, gas, fuelwood, nuclear energy and hydropower: the Fossil Fuel Footprint is the area required to sequester the emitted CO₂ taking into account CO₂ absorption by the sea etc.
• energy management - A program of well-planned actions aimed at reducing energy use, recurrent energy costs, and detrimental greenhouse gas emissions.
• energy recovery – the productive extraction of energy, usually electricity or heat, from waste or materials that would otherwise have gone to landfill.
• energy-for-land ratio - the amount of energy that can be produced per hectare of ecologically productive land. The units used are gigajoules per hectare and year, or GJ/ha/yr. For fossil fuel (calculated as CO₂ assimilation) the ratio is 100 GJ/ha/yr.
• enhanced greenhouse effect - the increase in the natural greenhouse effect resulting from increases in atmospheric concentrations of greenhouse gases due to emissions from human activities.
• ENSO (El Niño–Southern Oscillation) a suite of events that occur at the time of an El Niño; at one extreme of the cycle, when the central Pacific Ocean is warm and the atmospheric pressure over Australia is relatively high, the ENSO causes drought conditions over eastern Australia cf. El Niño, Southern Oscillation.
• environment - the external conditions, resources, stimuli etc. with which an organism interacts.
• environmental flows - river or creek water flows that are allocated for the maintenance of the waterway ecosystems.
• environmental indicator - physical, chemical, biological or socio-economic measure that can be used to assess natural resources and environmental quality.
• environmental movement (environmentalism) - both the conservation and green movements; a diverse scientific, social, and political movement. In general terms, environmentalists advocate the sustainable management of resources and stewardship of the natural environment through changes in public policy and individual behavior. In its recognition of humanity as a participant in ecosystems, the movement is centered around ecology, health, and human rights.
• environmental science - the study of interactions among physical, chemical, and biological components of the environment.
• epidemiology - the study of factors affecting the health and illness of populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.
• erosion - displacement of solids (sediment, soil, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms.
• Escherichia coli (E. coli) – a bacterium used as an indicator of faecal contamination and potential disease organisms in water.
• estuary - a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea.
• ethical consumerism - buying things that are made ethically i.e. without harm to or exploitation of humans, animals or the natural environment. This generally entails favoring products and businesses that take account of the greater good in their operations.
• ethical living – adopting lifestyles, consumption and shopping habits that minimise our negative impact, and maximise our positive impact on people, the environment and the economy cf. consumer democracy, sustainable living.
• eutrophication - the enrichment of waterbodies with nutrients, primarily nitrogen and phosphorus, which stimulates the growth of aquatic organisms.
• eutrophication - an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem.
• euxenic - with extremely low oxygen cf. anoxic.
• evaporation – water converted to water vapour.
• evapotranspiration (ET) – the water evaporating from the soil and transpired by plants.
• e-waste - electronic waste, especially mobile phones, televisions and personal computers.
• extended producer responsibility (EPR) (product take-back) - a requirement (often in law) that producers take back and accept responsibility for the responsible disposal of their products; this encourages the design of products that can be easily repaired, recycled, reused or upgraded.
• external water footprint – the embodied water of imported goods cf. internal water footprint.
• externality – (environmental economics) by-products of activities that affect the well-being of people or damage the environment, where those impacts are not reflected in market prices. The costs (or benefits) associated with externalities do not enter standard cost accounting schemes. The environment is often cited as a negatively affected externality of the economy (see economic externality).
• extinction event - (mass extinction, extinction-level event, ELE) - a sharp decrease in the number of species in a relatively short period of time.
• extinction - the cessation of existence of a species or group of taxa, reducing biodiversity.