Climate Change Glossary
Word Definitions Related to
Climate Change and Global Warming
Eccentricity
The extent to which the Earth's orbit around the Sun departs from a perfect circle.
Ecological Disturbance
E·co·lo·gi·cal Di·stur·bance ["E-k&-'lä-ji-k&l di-'st&r-b&n(t)s]. Ecological means related to the ecology, which is the totality or pattern of relations between organisms and their environment. An ecological disturbance is an event or circumstance that interrupts the relationship between organism and environment.
Ecosystem
Any natural unit or entity including living and non-living parts that interact to produce a stable system through cyclic exchange of materials.6
El Niño
translates from Spanish as 'the boy-child'. Peruvian fisherman originally used the term referring to the Christ as a child. This was used to describe the appearance, around Christmas, of a warm ocean current off the South American coast. Today, the term El Niño refers to the extensive warming of the central and eastern Pacific that leads to a major shift in weather patterns across the Pacific. In Australia, and more so for eastern Australia, El Niño events are associated with an increased probability of drier conditions.
El Niño - Southern Oscillation (ENSO)
El Niño, in its original sense, is a warm water current that periodically flows along the coast of Ecuador and Peru, disrupting the local fishery. This oceanic event is associated with a fluctuation of the intertropical surface pressure pattern and circulation in the Indian and Pacific Oceans, called the Southern Oscillation. This coupled atmosphere-ocean phenomenon is collectively known as El Niño-Southern Oscillation. During an El Niño event, the prevailing trade winds weaken and the equatorial countercurrent strengthens, causing warm surface waters in the Indonesian area to flow eastward to overlie the cold waters of the Peru current. This event has great impact on the wind, sea surface temperature, and precipitation patterns in the tropical Pacific. It has climatic effects throughout the Pacific region and in many other parts of the world. The opposite of an El Niño event is called La Niña.
Emission permit
Tradable allocation of entitlements by a government to an individual firm to emit a specific amount of a substance.
Emission scenario
A plausible representation of the future development of emissions of substances that are potentially radiatively active (e.g. greenhouse gases, aerosols), based on a coherent and internally consistent set of assumptions about driving forces (such as demographic and socio-economic development, technological change) and their key relationships.
Concentration scenarios, derived from emission scenarios, are used as input into a climate model to compute climate projections.
In IPCC (1992) a set of emission scenarios was presented which were used as a basis for the climate projections in IPCC (1996). These emission scenarios are referred to as the IS92 scenarios. In the IPCC Special Report on Emission Scenarios (Nakic´enovic´ et al., 2000) new emission scenarios, the so called SRES scenarios, were published some of which were used, among others, as a basis for the climate projections presented in Chapter 9 of this Report. For the meaning of some terms related to these scenarios, see SRES scenarios.
Emission standard
An amount of emission that may not be exceeded legally.
Emissions
The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere.
Emissions Factor
A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g., grams of carbon dioxide emitted per barrel of fossil fuel consumed).
Emissions scenario
See Emission scenario
Emissions trading
a scheme that allows companies either reduce emissions or pay for the right to pollute (with the money paid being used to reduce emissions elsewhere – often in developing countries).
Energy balance
Averaged over the globe and over longer time periods, the energy budget of the climate system must be in balance. Because the climate system derives all its energy from the Sun, this balance implies that, globally, the amount of incoming solar radiation must on average be equal to the sum of the outgoing reflected solar radiation and the outgoing infrared radiation emitted by the climate system. A perturbation of this global radiation balance, be it human induced or natural, is called radiative forcing.
Energy efficiency
is using less energy to provide the same amount of heating, cooling or other energy service. Usually refers to cutting energy wastage (like turning off unused lights, plant and equipment).
Energy Intensity
The ratio of energy consumption to a measure of the demand for services (e.g., number of buildings, total floorspace, floorspace-hours, number of employees, or constant dollar value of Gross Domestic Product for services).
Enhanced Greenhouse Effect
The concept that the natural greenhouse effect has been enhanced by anthropogenic emissions of greenhouse gases. Increased concentrations of carbon dioxide, methane, and nitrous oxide, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3), and other photochemically important gases caused by human activities such as fossil fuel consumption, trap more infra-red radiation, thereby exerting a warming influence on the climate. See greenhouse gas, anthropogenic, greenhouse effect, climate, global warming.7
Environment
En·vi·ron·ment [in-'vI-r&(n)-m&nt]. The complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism (a living thing) or an ecological community (a collection of living things) and ultimately determine its form and survival. The circumstances, objects, and conditions that surround each of us.
Equilibrium and transient climate experiment
An equilibrium climate experiment is an experiment in which a climate model is allowed to fully adjust to a change in radiative forcing. Such experiments provide information on the difference between the initial and final states of the model, but not on the time-dependent response. If the forcing is allowed to evolve gradually according to a prescribed emission scenario, the time dependent response of a climate model may be analysed. Such experiment is called a transient climate experiment. See: Climate projection.
Equivalent CO2 (carbon dioxide)
The concentration of CO2 that would cause the same amount of radiative forcing as a given mixture of CO2 and other greenhouse gases.
Eustatic sea-level change
A change in global average sea level brought about by an alteration to the volume of the world ocean. This may be caused by changes in water density or in the total mass of water. In discussions of changes on geological time-scales, this term sometimes also includes changes in global average sea level caused by an alteration to the shape of the ocean basins. In this Report the term is not used with that sense.
Evaporation
is the process by which a liquid becomes a gas.
Evapotranspiration
The combined process of evaporation from the Earth's surface and transpiration from vegetation.
External forcing
See: Climate system.
Externalities
By-products of activities that affect the well-being of people or damage the environment, where those impacts are not reflected in market prices.
Extratropical cyclones
sometimes called mid-latitude cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics.
Extreme weather event
An extreme weather event is an event that is rare within its statistical reference distribution at a particular place. Definitions of “rare” vary, but an extreme weather event would normally be as rare as or rarer than the 10th or 90th percentile. By definition, the characteristics of what is called extreme weather may vary from place to place.
An extreme climate event is an average of a number of weather events over a certain period of time, an average which is itself extreme (e.g. rainfall over a season).
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Endemic
Describes a species (or other unit of classification) that occurs in one particular region in all months of the year, and in all years. For example, the platypus is endemic to southeast Australia, and malaria is endemic to parts of Africa.
