The climate-based definitions are from the Oak Ridge National Laboratory's (1990) glossary entitled "Carbon Dioxide and Climate." The economic-based definitions are from Sharp, Register, and Leftwich (1988), "Economics of Social Issues," Business Publications, Inc., Plano, Texas.
AdaptationThe adjustment of an organism or population to a new or altered environment through genetic changes brought about by natural selection.
AerosolParticulate material, other than water or ice, in the atmosphere ranging in size from approximately 10-3 to larger than 102 µm in radius. Aerosols are important in the atmosphere as nuclei for the condensation of water droplets and ice crystals, as participants in various chemical cycles, and as absorbers and scatterers of solar radiation, thereby influencing the radiation budget of the earth-atmosphere system, which in turn influences the climate on the surface of the earth.
Airborne fractionThe portion of CO2 released from all energy consumption and land use activities that remains in the atmosphere as opposed to the amounts absorbed by plants and oceans. How the world's total carbon is partitioned among the oceanic, terrestrial, and atmospheric pools is determined by complex biogeochemical and climatological interactions.
AlbedoThe fraction of the total solar radiation incident on a body that is reflected by it.
AtmosphereThe envelope of air surrounding the earth and bound to it by the earth's gravitational attraction. Studies of the chemical properties, dynamic motions, and physical processes of this system constitute the field of meteorology.
Biological productivityThe amount of organic matter, carbon, or energy content that is accumulated during a given time period.
BiomassThe total dry organic matter or stored energy content of living organisms that is present at a specific time in a defined unit (community, ecosystem, crop, etc.) of the earth's surface.
BiosphereThe portion of earth and its atmosphere that can support life. The part (reservoir) of the global carbon cycle that includes living organisms (plants and animals) and life-derived organic matter (litter, detritus). The terrestrial biosphere includes the living biota (plants and animals) and the litter and soil organic matter on land, and the marine biosphere includes the biota and detritus in the oceans.
BiotaThe animal and plant (fauna and flora) life of a given area.
Carbon-based resourcesThe recoverable fossil fuel (coal, gas, crude oils, oil shale, and tar sands) and biomass that can be used in fuel production and consumption.
Carbon budgetThe balance of the exchanges (incomes and losses) of carbon between the carbon reservoirs or between one specific loop (e.g., atmosphere-biosphere) of the carbon cycle. An examination of the carbon budget of a pool or reservoir can provide information about whether the pool or reservoir is functioning as a source or sink for CO2.
Carbon cycleAll parts (reservoirs) and fluxes of carbon; usually thought of as a series of the four main reservoirs of carbon interconnected by pathways of exchange. The four reservoirs, regions of the earth in which carbon behaves in a systematic manner, are the atmosphere, terrestrial biosphere (usually includes freshwater systems), oceans, and sediments (includes fossil fuels). Each of these global reservoirs may be subdivided into smaller pools ranging in size from individual communities or ecosystems to the total of all living organisms (biota). Carbon exchanges from reservoir to reservoir by various chemical, physical, geological, and biological processes.
Carbon densityThe amount of carbon per unit area for a given ecosystem or vegetation type, based on climatic conditions, topography, vegetative-cover type and amount, soils, and maturity of the vegetative stands.
Carbon dioxide fertilizationEnhancement of plant growth or of the net primary production by CO2 enrichment that could occur in natural or agricultural systems as a result of an increase in the atmospheric concentration of CO2.
Carbon sinkA pool (reservoir) that absorbs or takes up released carbon from another part of the carbon cycle. For example, if the net exchange
between the biosphere and the atmosphere is toward the atmosphere, the biosphere is the source, and the atmosphere is the sink.
Carbon sourceA pool (reservoir) that releases carbon to another part of the carbon cycle.
ChlorofluorocarbonsA family of inert nontoxic and easily liquified chemicals used in refrigeration, air conditioning, packaging, and insulation or as solvents or aerosol propellants. Because they are not destroyed in the lower atmosphere, they drift into the upper atmosphere, where their chlorine components destroy ozone.
ClimateThe statistical collection and representation of the weather conditions for a specified area during a specified time interval, usually decades, together with a description of the state of the external system or boundary conditions. The properties that characterize the climate are thermal (temperatures of the surface air, water, land, and ice), kinetic (wind and ocean currents, together with associated vertical motions and the motions of air masses, aqueous humidity, cloudiness and cloud water content, groundwater, lake lands, and water content of snow on land and sea ice), and static (pressure and density of the atmosphere and ocean, composition of the dry air, salinity of the oceans, and the geometric boundaries and physical constants of the system). These properties are interconnected by the various physical processes such as precipitation, evaporation, infrared radiation, convection, advection, and turbulence.
Climate changeThe long-term fluctuations in temperature, precipitation, wind, and all other aspects of the earth's climate. External processes, such as solar-irradiance variations, variations of the earth's orbital parameters (eccentricity, precession, and inclination), lithosphere motions, and volcanic activity, are factors in climatic variation. Internal variations of the climate system also produce fluctuations of sufficient magnitude and variability to explain observed climate change through the feedback processes interrelating the components of the climate system.
CloudA visible mass of condensed water vapor particles or ice suspended above the earth's surface. Clouds may be classified on their visual appearance, height, or form.
Cloud albedoReflectivity that varies from less than 10 to more than 90 percent of the insolation and depends on drop sizes, liquid water content, water vapor content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the greater the liquid water content, the greater the cloud albedo, if all other factors are the same.
Cloud feedbackThe coupling between cloudiness and surface air temperature in which a change in surface temperature could lead to a change
in clouds, which could then amplify or diminish the initial temperature perturbation. For example, an increase in surface air temperature could increase the evaporation; this in turn might increase the extent of cloud cover. Increased cloud cover would reduce the solar radiation reaching the earth's surface, thereby lowering the surface temperature. This is an example of negative feedback and does not include the effects of longwave radiation or the advection in the oceans and the atmosphere, which must also be considered in the overall relationship of the climate system.
Cost-benefit analysisDetermination of and comparison of the costs and the benefits of an activity to evaluate its economic worth and the extent, if any, to which it should be carried on.
DeforestationThe removal of forest stands by cutting and burning to provide land for agricultural purposes, residential or industrial building sites, roads, etc., or by harvesting the trees for building materials or fuel. Oxidation of organic matter releases CO2 to the atmosphere, and regional and global impacts may result.
DemandThe set of quantities of a good or service per unit of time that buyers would be willing to purchase at various alternative prices of the item, other things being equal.
Developed countriesCountries with relatively higher labor quality, relatively large accumulations of capital, and relatively higher levels of technology, all leading to relatively high living standards.
Discount rateThe rate of interest the Federal Reserve banks, charge commercial banks when commercial banks borrow from the Fed.
EcosystemThe interacting system of a biological community and its non-living environmental surroundings.
EfficiencyThe extraction of the greatest possible value of product output from given inputs of resources.
Elasticity of demand, priceThe responsiveness of the quantity demanded of a product to changes in its price. Measured by the percentage change in quantity divided by the percentage change in price.
Elasticity of supply, priceThe responsiveness of the quantity offered of a product to changes in its price. measured by the percentage change in quantity divided by the percentage change in price.
EmissionsMaterials (gases, particles, vapors, chemical compounds, etc.) that come out of smokestacks, chimneys, and tailpipes.
EmissivityThe ratio of the radiation emitted by a surface to that emitted by a black body at the same temperature.
ExternalitiesBenefits or costs incurred in the production or consumption of goods and services that do not accrue to the producing or consuming unit, but rather accrue to the remainder of the society.
Feedback mechanismsA sequence of interactions in which the final interaction influences the original one.
Fossil fuelAny hydrocarbon deposit that can be burned for heat or power, such as petroleum, coal, and natural gas.
Free ridersThose who receive social spillover benefits without paying the costs of producing the goods or services that yield them.
Full cost pricingA situation in which the price of a product is equal to its average costs of production.
GeosphereThe solid mass (lithosphere) of the earth as distinct from the atmosphere and hydrosphere or all three of these layers combined.
Greenhouse gasesThose gases, such as water vapor, carbon dioxide, tropospheric ozone, nitrous oxide, and methane, that are transparent to solar radiation but opaque to longwave radiation. Their action is similar to that of glass in a greenhouse.
Gross national product, currentThe value of an economy's annual output of goods and services in final form at current prices.
Heat island effectA ''dome" of elevated temperatures over an urban area caused by the heat absorbed by structures and pavement.
Implicit costsCosts of production incurred by producing a unit for the use of self-owned, self-employed resources.
Infrared radiationElectromagnetic radiation lying in the wavelength interval from 0.7 µm to 1000 µm. Its lower limit is bounded by visible radiation, and its upper limit by microwave radiation. Most of the energy emitted by the earth and its atmosphere is at infrared wavelength. Infrared radiation is generated almost entirely by large-scale intramolecular processes. The tri-atomic gases, such as water vapor, carbon dioxide, and ozone, absorb infrared radiation and play important roles in the propagation of infrared radiation in the atmosphere.
InvestmentThe purchase by economic units of such real assets as land, building, equipment, machinery, and raw and semifinished materials.
Lesser developed countriesCountries with relatively low living standards, usually the result of relatively low labor quality, relatively scarce capital, and relatively low levels of technology.
Marginal benefitsThe increase or decrease in the total benefits yielded by an activity from a one-unit change in the amount of the activity carried on.
Marginal costsThe change in total costs resulting from a one-unit change in the output of a good or service.
MarketThe area within which buyers and sellers of a good or service can interact and engage in exchange.
ModelingAn investigative technique that uses a mathematical or physical representation of a system or theory that accounts for all or some of its known properties. Models are often used to test the effects of changes of system components on the overall performance of the system.
Negative feedbackAn interaction that reduces or dampens the response of the system in which it is incorporated.
NutrientAny substance assimilated by living things that promotes growth.
Ocean mixingProcesses that involve rates of advection, upwelling/downwelling, and eddy diffusion and that determine how rapidly excess atmospheric carbon dioxide can be taken up by the oceans.
OzoneA molecule made up of three atoms of oxygen. In the stratosphere, it occurs naturally and it provides a protective layer shielding the earth from ultraviolet radiation and subsequent harmful health effects on humans and the environment. In the troposphere, it is a chemical oxidant and major component of photochemical smog.
PhotosynthesisThe manufacture by plants of carbohydrates and oxygen from carbon dioxide and water in the presence of chlorophyll with sunlight as the energy source. Oxygen and water vapor are released in the process. Photosynthesis is dependent on favorable temperature and moisture conditions as well as on the atmospheric carbon dioxide concentration. Increased levels of carbon dioxide can increase net photosynthesis in many plants.
PhytoplanktonThat portion of the plankton community made up of tiny plants (e.g., algae and diatoms).
Planetary albedoThe fraction (approximately 30 percent) of incident solar radiation that is reflected by the earth-atmosphere system and returned to space, mostly by backscatter from clouds in the atmosphere.
Public goodsGoods and services of a collectively consumed nature, usually provided by governmental units.
Soil CarbonA major component of the terrestrial biosphere pool in the
carbon cycle. Organic soil carbon estimates, rather than total soil carbon, are generally quoted. The amount of carbon in the soil is a function of historical vegetative cover and productivity, which in turn is dependent upon climatic variables.
Spillover benefits, socialBenefits from consumption or production activities that accrue to persons other than those doing the consuming or producing. Examples include the benefits of education services to those other than the students receiving them. See also, Externalities.
Spillover costs, socialCosts of consumption and production imposed on persons or economic units other than those doing the consuming or producing. See also, Externalities.
SupplyThe set of quantities of a good or service per unit of time that sellers would be willing to place on the market at various alternative prices of the item, other things being equal.
Supply curve of a firmA curve showing the quantities per unit of time a firm will place on the market at alternative price levels, other things being equal. The concept is valid for a competitive firm only, and coincides with its marginal cost curve.
TechnologyThe know-how and the means and methods available for combining resources to produce goods and services.
Trace gasA minor constituent of the atmosphere. The most important trace gases contributing to the greenhouse effect are water vapor, carbon dioxide, ozone, methane, ammonia, nitric acid, nitrous oxide, ethylene, sulfur dioxide, nitric oxide, dichlorofluoromethane or Freon 12, trichlorofluoromethane or Freon 11, methyl chloride, carbon monoxide, and carbon tetrachloride.
UpwellingThe vertical motion of water in the ocean by which subsurface water of lower temperature and greater density moves toward the surface of the ocean. Upwelling occurs most commonly among the western coastlines of continents, but may occur anywhere in the ocean. Upwelling results when winds blowing nearly parallel to a continental coastline transport the light surface water away from the coast. Subsurface water of greater density and lower temperature replaces the surface water, and exerts a considerable influence on the weather of coastal regions. Carbon dioxide is transferred to the atmosphere in regions of upwelling. This is especially important in the Pacific equatorial regions, where 1 to 2 Gt C/yr may be released to the atmosphere. Upwelling also results in increased ocean productivity by transporting nutrient-rich waters to the surface layer of the ocean.