Glossary

Glossary item

Definition

atom

the smallest amount of a chemical element that still retains the properties of that element.

biodiversity

a contraction of 'biological diversity', in general it describes the variety of life on Earth and specifically the total sum of the genes, species, habitats and ecosystems in a given environment.

Brundtland report

a report for the United Nations on sustainable development, published in 1987.

carbon dioxide

a chemical compound consisting of carbon and oxygen. A molecule of carbon dioxide consists of one atom of carbon and two atoms of oxygen ('di' means 'two'). CO₂ is produced in respiration and combustion reactions and is consumed in photosynthesis. Carbon dioxide is the most important greenhouse gas released as a result of human activity.

chlorofluorocarbons (CFCs)

a family of compounds containing carbon, fluorine and chlorine atoms. CFCs are chemically inert and stable and were formerly used as refrigerants, aerosol propellants and in foams. Following the discovery that they are responsible for ozone layer depletion their production and use were banned in many countries.

concentrate and contain

to deal with pollutants by containing them in a comparatively small space and attempting to isolate them from the wider environment (the opposite of dilute and disperse).

DDT

dichloro-diphenyl-trichloroethane. A pesticide developed during the Second World War. It is highly effective, but it persists in the environment and can be fatal to fish and bird life. Due to this problem the production and use of DDT is banned in most countries. DDT is an organochlorine compound.

deforestation

the destruction of forests in order to use the wood or to clear the land for other use such as agriculture.

dilute and disperse

a method of dealing with pollution by discharging the pollutants into an environment where they disperse rapidly, reducing the potential for causing damage. This strategy can only be adopted after a thorough analysis of its impact on all aspects of the environment (see also concentrate and contain).

economic and technical potential

the savings that could be made by the widespread use of existing environmentally efficient appliances.

end-of-pipe

control of pollution by removing potential pollutants from an effluent stream (for example removing the NOx from vehicle exhausts or the sulphur dioxide from coal-fired power station emissions).

energy labelling

a compulsory EU labelling scheme for consumer products, such as refrigerators, that meet given levels of energy efficiency and, sometimes, other environmental or performance criteria.

energy standards

regulations specifying the minimum efficiency of electrical appliances (see also environmental standards).

flora and fauna

the plants (flora) and animals (fauna) in a given area.

food chain

a series of organisms beginning with plants where each stage feeds on the stage below it. In general, the series consists of plants–herbivores– carnivores

foul and flee

a way of dealing with pollution by carrying out a polluting activity until local pollutant levels become too high and then moving to another area and repeating the process. This was common in pre-industrial days, but began to be phased out during the Industrial Revolution.

Freons

a proprietary name (or trade name) for a particular brand of CFCs (chlorofluorocarbons).

global climate change

a warming of the global climate believed to be due to the accumulation of greenhouse gases in the atmosphere and caused by the releases of these gases through human activity.

greenhouse effect

mechanism whereby incoming solar radiation is trapped by carbon dioxide and other greenhouse gases in the Earth's atmosphere in the same way as heat is trapped by glass in a greenhouse.

greenhouse gases

gases which have the effect of warming the global climate. Without them the Earth's temperature would be some tens of degrees Celsius colder than it is now (and life would not have evolved in its current form), but current concern is about global climate change caused by their increase in the atmosphere since the Industrial Revolution. The principal greenhouse gas is carbon dioxide, others are methane, nitrous oxide and CFCs.

habitat

place with a particular kind of environment where a given organism lives, e.g. coniferous forest for the red squirrel.

HCFCs

or hydrochlorofluorocarbons. Designed to be a replacement for CFCs, they have a lower potential for destroying the ozone layer (typically less than a tenth), but most are strong greenhouse gases. HCFC use is to be phased out over the period 2020–2040 (see also HFCs).

heat

energy due to the temperature of a substance, and the kinetic energy of the molecules composing it. Also called thermal energy.

HFCs

or hydrofluorocarbons. Designed as a replacement for CFCs. As they contain no chlorine, they do not deplete the ozone layer and are not covered by the Montreal Protocol, but they are strong greenhouse gases (see also HCFCs).

hydrocarbons

compounds of hydrogen and carbon only. One of the main uses of hydrocarbons is in fuels. Methane, the simplest hydrocarbon, is the main constituent in natural gas.

Industrial Revolution

the transformation of the British economy from a rural to an urban one during the 18th and 19th centuries. This period was characterised by the development of industrial processes, the development of factories and the growth of cities.

infrared (IR) rediation

all bodies, including the Sun and the Earth, give out and absorb energy in the form of IR radiation. The infrared can be thought of as radiant heat and refers to radiation with a wavelength longer than that of light. The range of IR wavelengths given out by a body depends on its temperature and the IR from the Earth is quite different in quality to that coming from the Sun.

kilowatt-hour (kWh)

1 kWh is equivalent to the 'Unit' used in metering domestic electricity. It is a quantity of energy equal to 3600 kJ. (The energy consumed by an electrical appliance in kWh can be calculated by multiplying the power consumption (in kW) by the length of time (in hours) the appliance is operated for.)

Kyoto climate change protocol

an international agreement stemming from the 1997 climate change conference held in the Japanese city of Kyoto. Under this protocol, most industrialised countries agreed a legally binding obligation to reduce the emission of gases (particularly carbon dioxide) contributing to climate change.

laissez faire

in environmental tds, taking no action to control pollution but letting the natural environment absorb (and in some cases treat) the pollutant. In economic tds it means a belief that the workings of a free economic market will always produce the best result (as opposed to regulation by any agency).

Maslow's hierarchy of human needs

a way of looking at needs which stretches from basic needs of food, shelter and water at the base up to the higher needs of love and truth at the top.

molecule

the smallest part of a substance (chemical element or compound) which can exist independently.

Montreal Protocol

an international agreement signed in 1987 to phase out the use of CFCs and other substances that damage the ozone layer. This protocol has been signed by around 60 countries (but not by China or India).

organochlorine compounds

a class of chemicals that are products or unwanted by-products of the organic chemicals industry. Many of them are highly toxic and accumulate in the environment or in living things and degrade at a very slow rate.

organophosphates

a group of chemicals developed from nerve gases. They are used as pesticides and degrade much more rapidly than organochlorine compounds. However, the long-td environmental effects of organophosphates are not known.

ozone

a reactive form of oxygen whose molecules contain three oxygen atoms. Ozone is a pollutant in the lower atmosphere (troposphere), but its presence in the upper atmosphere (stratosphere) provides the protection from ultra-violet radiation necessary for life to have evolved on Earth.

ozone depletion (ozone hole)

a reduction in the level of ozone in the upper atmosphere (or stratosphere) (see also chlorofluorocarbons).

ozone layer

the zone of the upper atmosphere of about 15–30 km above the Earth (i.e. the lower stratosphere) where a comparatively high concentration of ozone is present. The ozone absorbs ultraviolet radiation from the Sun, so preventing excessive amounts from reaching the Earth.

polymers

large molecules consisting of repeated structural units; plastics.

precautionary principle

the assumption that any action which might cause environmental change, for example the release of a substance into the environment, is environmentally damaging until proved otherwise.

species

in the classification of living organisms, it is the smallest unit of classification commonly used; for the majority of plants and animals it is a group of individuals able to breed among themselves but not able to breed with organisms of other groups.

stratosphere

the layer of the atmosphere above the lower atmosphere, or troposphere, where our weather occurs. Its height varies with season and latitude, but usually lies between 10–15 km and 60–80 km above the Earth's surface.

sulphur dioxide

sometimes referred to as SO₂ or SO_x, an acid gas formed by the combustion of fuels containing sulphur (such as coal). Sulphur dioxide is responsible for acid rain which damages buildings and ecosystems and can cause localised respiratory problems.

sustainability

a concept that combines environmental impacts of human activities with social and economic concerns and relates to the capacity of the Earth to accommodate them (see also sustainable development).

sustainable development

a system of development that allows current generations to develop economically and socially without passing on insoluble problems to future generations. Often defined as 'development that meets the needs of the present without compromising the ability of future generations to meet their own needs' (see also sustainability).

toxicity

a measure of the potential damage to life posed by a particular substance or toxin. It is related to both concentration and time of exposure.

ultraviolet (UV) radiation

the energy radiating from the Sun with a wavelength shorter than visible light but longer than that of X-rays. The more energetic part of the UV radiation from the Sun is damaging to human and ecosystem health, but most of this is removed by the ozone layer before it reaches the Earth's surface.

value

a personal view of an issue or of the importance of taking or preventing a particular action. Values are subjective and cannot be described in tds of 'right and wrong'.