Glossary

CLIMATE CHANGE IN CONTEXT PREVIOUS | NEXT

 

-A-

Ablation Loss of ice in a glacier due to evaporation and melting
Abrasion Wearing away of rocks by the action of wind, water or ice carrying particles of dust and sand. A process similar to sandpapering
Abyssal Relating to the deep areas of the earth and oceans and the organisms inhabiting those environments
Accumulation The addition of ice and snow to a glacier
Advection The transfer of heat, cold, or other atmospheric properties by the horizontal movement of a mass of air
Albedo The amount of light reflected from a surface. Snow has a high albedo
Alluvial fan deltas Fan shaped mass of loose rock material deposited on a flood plain
Altitude The vertical distance above a reference point (usually sea level)
Ancillary benefits Positive side effects of policies or actions
Angiosperm Flowering plants in which the seeds are enclosed in fruit
Angstrom Unit of wavelength for electromagnetic radiation. 1 Angstrom Unit is equal to one ten-billionth of a meter. (10-10 meters)
Annex I countries Industrialized and developing countries expected to participate in the Kyoto Agreement. These countries are committed to returning their emissions outputs to 1990 levels
Anthropogenic Changes in the natural world resulting from or influenced by human activities
Anthropogenic forcing The activities of humankind which cause changes in the structure and processes of the environment
Aphelion Phase in orbit when the Earth is farthest from the sun
Aquifer A layer of porous rock between layers of non-porous (impermeable) rock. This structure allows water to move great distance through this ‘pipeline’, sometimes emerging at a shoreline (coastal aquifer) or floodplain (floodplain aquifer)
Arctic Oscillation An atmospheric circulation pattern in which the atmospheric pressure over the polar areas varies in opposition with that over the middle latitudes on time scales varying from weeks to decades
Asthenosphere The zone of hot rock, believed to be in a plastic condition, underlying the solid lithosphere (the Earth’s crust)
Atmosphere The layers of air which surrounds the Earth which consist mainly of the permanent gases such as nitrogen, oxygen, argon and helium and variable gases such as ozone, sulfur dioxide, and carbon dioxide (about 0.04%). The atmosphere decreases in density and air pressure as elevation increases, becoming almost non-existant at altitudes above 100 kilometers
Atoll Coral reef forming a circle around a central lagoon
Australasia The islands of the southern Pacific Ocean including Australia, New Zealand, New Guinea and adjacent islands

 

-B-

Bacteriocin Toxin produced by one bacteria, which kills another, usually in a related class
Basal slip Movement of an entire glacier over underlying ground surface
Batholith Large body of intrusive igneous rock, usually granite, forming deep underground
Bedrock Solid rock which lies below the soil. On the prairies it may be several feet below the surface; on hillsides, only a few inches
Beheaded stream Stream that has had its flow captured by another stream
Benthos The biographic region at the bottom of a sea, ocean, or lake, and the organisms living there
Bioaccumulation The increase in the concentration of poisons in animal tissue towards the top of the food chain
Biogeochemistry A branch of geochemical dealing with the relationship of plants and animals to the global distribution by chemical elements
Biomass The total dry mass of an animal or plant population
Biosphere Area of the Earth’s crust, ocean, and atmosphere where life is found
Braided stream A stream or river that splits into smaller channels that rejoin further downstream

 

-C-

Calving Breaking off of pieces of glaciers and ice shelves that then become icebergs
Canyon Deep, steep-sided valley created by river erosion
Carbon 14 Atmospheric carbon dioxide contains a constant proportion of radioactive 14C, formed by cosmic radiation. Living organisms absorb this unstable isotope in the same proportion. The proportion of stable 12C to the residual 14˚C indicates the period elapsed since death
Carbon sinks Structures or processes able to absorb carbon dioxide, thus removing it from the atmosphere
Cardiovascular disease Disease of the heart and blood vessels
Cargo dirigibles Large gas-filled (helium) airships proposed to transport heavy loads in wilderness areas
Catalytic Reactions Reactions that are affected by the presence of an agent (catalyst) which is itself unaffected by the reaction
Cataracts Clouding of the lens of the eye due to degeneration
Cavity A natural recess or chamber with an entrance at the surface
CFCs A hydrocarbon in which some or all of the hydrogen atoms have been replaced by chlorine or fluorine. It has a depletive effect on stratospheric ozone
Cholera An acute bacterial infection spread by infected food and water. The symptoms include severe vomiting and diarrhea, painful cramps and drying of body tissue
Circumpolar High latitude regions surrounding the poles
Climate Pattern of weather conditions of a place or region, based on daily weather records over a period of time (usually 20 years)
Confluence Point at which two or more streams join to form a larger single stream
Continental Drift Slow movement of the continents on the surface of the earth
Convection rain Precipitation caused by the warming of moist air by thermal conduction from the heated land surface. The moist warm air rises, cools, and forms clouds which drop heavy torrential rain
Convection Heat transfer from place to place within a gas or liquid
Cordilleran type Mountain system consisting of series of parallel ranges or ridges (e.g. Rockies or Andes)
Craton Large stable block of the Earth’s crust, relatively unaffected by tectonic activity, typically Precambrian in age (over 500 million years old)
Crevasse A vertical crack or fissure often deep and wide, a glacier or ice sheet
Cryosphere The region at the Earth’s surface that is frozen throughout the year
Cuesta (or escarpment) Hill or ridge with a steep slope on one side and gentler slope (or ‘dip’) on the other
Cycads Gymnosperm plants featuring broad unbranched stems with large leaves at the end
Cyclone A circular movement of winds revolving around a low pressure centre

 

-D-

Delta Triangular shaped formation of sediment deposited at the mouth of the river
Dendrochronology The analysis of tree rings to determine past climate conditions
Denuded Bedrock exposed by the erosion of overlying material
Direct relationship Is a positive relationship between two variables such that as one variable increases, so does the other
Discernible Able to be sensed
Drift Material deposited by drifting icebergs. Loose material (sand, gravel, boulder, clay, etc.) deposited by glacier or melt water of glaciers

 

-E-

Ecological thinking A sensitivity to the need to preserve the balances in nature and the relationships among the natural systems of the Earth
El Niño Intense and prolonged warming of the eastern Pacific Ocean every few years, producing unusual weather
Electromagnetic spectrum The range of wavelengths from gamma rays, through x-rays ultra-violet, visible light, infrared and radio waves
Emissivity The radiation emitted by an object compared to that of a perfect black-body radiator at the same temperature
Encephalitis A disease characterized by the progressive destruction of the nerve fibres in the brain, causing paralysis
Endemic A species or family confined to a particular region and thought to have originated there
Endothermy The absorption of heat energy
ENSO El Niño Southern Oscillation. This is the strongest natural fluctuation of climate on interannual time scales
Environment The physical, chemical, and biological surroundings of an object
Equatorial current A low latitude surface ocean current, generally flowing east to west
Equilibrium Model A representation of the relationships between various forces
Esker Long narrow ridge formed by a subglacial stream carrying sand and gravel
Estuaries An inlet of the sea at the mouth of a river
Eukaryotic Higher or more complex organisms (animals, plants, and fungi). The cells have nuclear membranes
Eutrophication Decay of organic matter in a lake, with resultant loss of oxygen in the water
Evapotranspiration The total water loss from a particular area being the sum of evaporation from the soil and transpiration from vegetation

 

-F-

Fault A fracture or break in a series of rocks along which some displacement has taken place
Fauna A collective term denoting the animals occurring in a particular region or period
Feedback loop The path by which some of the output of a system is returned to the input
Firn (or névé) Granular snow in a state halfway between snow and ice, subsequently compacted to form ice
Foraminifera Single-celled organisms which produce a protective shell of limestone or chiton
Forearc and backarc A sedimentary basin developed in the gap between a volcanic arc and its subduction zone

 

-G-

Gabbro A coarse grained group of rocks formed within the Earth’s crust
Gamma-rays Electromagnetic radiation of high quantum energy emitted after nuclear reactions or by radioactive atoms
GDP Gross Domestic Product. The sum total of all goods and services produced in a country in one year
Geological The study of the planet earth and the physical and chemical process affecting its structures
Germination The beginning of growth in a seed, spore, or zygote following a dormant period
Glacial trough Feature formed when a glacier widens and deepens a valley that was originally V-shaped. The valley becomes much deeper and U-shaped. The upper slopes tend to be very steep, while the lower have a gentler descent
Gondwanaland Southern part of Pangaea, the great land mass prior to the drifting of the continents (which began about 200 million years ago). It consisted of Africa, Australia, India and Antarctica
Gorge Narrow steep-sided valley formed by river erosion
Graben A rift valley, formed by the subsiding of rock between two parallel faults
Gradient Slope of the land, shown on contour maps by the distance between the contour lines
Green roof projects The planting of vegetation on rooftops of buildings
Greenhouse effect Warming of the lower levels of the atmosphere as a result of the retention and radiation of solar heat
Greenhouse gas emissions Gases such as carbon dioxide and methanol that increase global temperatures by trapping solar electromagnetic radiation
Gymnosperm A plant where seeds are not enclosed within an ovule or fruit (e.g. conifers)

 

-H-

Heinrich events Episodes during the last ice age with ice- rafted debris deposited on the sea floor
Horst A elongated uplifted block bounded by faults along its length
Hurricane Massive revolving storm that produces winds over 120 km/hr and heavy rainfall
Hydrological cycle The evaporation and condensation of water on a world scale
Hydrosphere All waters (liquid and solid) on the surface of the earth oceans, lakes, rivers, aquifers, and ice

 

-I-

Ice Age Long period of colder climate when snow and ice covered large areas of the Earth
Ice field Extensive area of interconnected glaciers in a mountain region, or of pack ice at sea
Ice sheet Large expanse of snow and ice that covers a land mass, for example Antarctica
Ice shelf Sheet of floating ice
Icecap Large expanse of ice and snow, covering the summit area of a mountain, an island, or a flat land mass
Icefall Section of a glacier where an abrupt change of gradient causes the ice to go down a steep slope causing intense crevassing
Igneous Rock formed by the molten material from volcanoes. There are two types intrusive molten material within the earth’s crust forced into older rock or between layers of older rock (e.g. granite); and extrusive molten material that has been ejected onto the earth’s surface (e.g. lava, volcanic ash)
Inertia The property of a body to oppose changes in its motion
Insolation Amount of energy received from the sun
Interglaciation Long period of time (10,000+ years) characterized by climatic conditions associated with minimum glacial extent
Interstade Short period of time (less than 10,000 years) characterized by climatic conditions associated with minimum glacial extent
Intertidal zone The area of shoreline covered by seawater at high tide and exposed to the air at low tide
Ionosphere A region of the Earth’s atmosphere beginning at an altitude of about 75 km and extending to an indefinite height. This is where free electrons and ions (which affect radio waves) are produced by solar radiation
Irradiance The flow of radiant energy per unit area (expressed in watts/meter2)
Irrigation withdrawals The removal of water from rivers, lakes, and wells for the purpose of agriculture
Isostasy A state of balance of the Earth’s land masses whereby some areas are rising and others sinking as material is eroded and deposited
Isotope One of or set of chemically identical atoms which have the same atomic number but different mass numbers

 

-J-

Jet stream Strong current of air blowing through the atmosphere at a high altitude, generally from west to east and at speeds up to 300 km/hr
Joint Geological vertical or near-vertical crack in rock

 

-K-

Kyoto target A set of emissions requirements for signatory nations to meet. The requirements are generally based on the level of emissions each nation had in 1990

 

-L-

Latitude Angular distance north or south of the Equator, measured at an angle from the Earth’s center. Lines of latitude are parallel to the Equator that is 0˚ Latitude
Laurasia Northern part of the ancient super-continent of Pangaea. It consisted of North America, Europe, and Asia
Limestone Rock formed on the bed of a warm sea by accumulation of dead sea creatures
Lithosphere Outer rigid shell of the earth which forms its surface. It extends down to depths of about 40 km and ‘floats’ on the denser asthenosphere below it
Loess Wind-blown soil consisting of very fine particles of clay
Lyme Disease An acute inflammatory disorder spread by ticks found in heavily wooded areas in summer

 

-M-

Magma Molten rock, including dissolved water and gases formed at a depth and remaining or moving within the crust. If it flows onto the surface it is called lava
Mangroves Low trees noted for their dense, interlacing above ground roots; found in marshes and tidal shores
Mantle The part of the earth between the lithosphere and the core, (from 40 km to 2900 km). The upper part of the mantle is the asthenosphere
MBP Millions of years before the present
Mean The average of a set of values
Meander Bend or curve in the course of a river
Meltwater Water created by the melting of snow and ice
Metamorphic rocks Sedimentary and igneous rock changed by heat or pressure to form a new type of rock. For example, limestone under heat and pressure becomes marble
Meteorologist A scientist who studies and reports on the changing conditions of the earth’s atmosphere
Micro-organism An organism of microscopic or submicroscopic size, especially a bacterium or protozoan
Milankovitch Cycles The collective effect of changes in the Earth’s movements upon its climate
Mitigation The influencing effect of a factor or force on a given situation
Monsoon A seasonal wind, usually bringing heavy rainfall to regions in southern and southeast Asia
Moraine A distinct accumulation of unsorted rock debris deposited directly from a melting glacier
MY Million years

 

-N-

NAO North Atlantic Oscillation. The opposing variations of atmospheric pressure near Iceland (low) and the Azores (high). It is the dominant mode of climate variability in the North Atlantic
Net Solar Radiation A measure of the incoming radiation incident on the earth’s surface minus the outgoing energy radiated by the earth itself
Niagara Escarpment Steep cliff (scarp) which runs north from Queenston to Tobermory in Ontario

 

-O-

Obliquity Angle of the Earth’s rotational axis from the plane of its orbit around the sun
Ocean basins Depressions on the surface of the lithosphere occupied by an ocean
Orogenesis Process of mountain formation, especially by volcanism or by folding and faulting of the earth’s crust
Orographic uplift Movement upwards of air masses encountering mountain ranges
Orography A recording of distance and elevation over land surface with the information used to create topographic maps
Outlier Mass of newer rocks surrounded by older rocks
Outwash plain An area built up by the sand and gravel brought down by streams flowing from a glacier or an ice sheet
Oxidation Chemical reaction of oxygen with other elements
Ozone layer Protective layer of ozone surrounding earth

 

-P-

Paleoclimatology Study of prehistoric climates
Paleogeology Study of ancient rocks
Paleoproxy data Information about ancient climate obtained through the examination of tree rings, corals, etc.
Pangea Name given to vast land mass (a ‘supercontinent’) which, 200 millions of years ago, was the only land on the Earth
Peneplain An extensive, nearly flat area of the earth’s surface, resulting from erosional processes over a long time
Perihelion Phase in its orbit when the Earth is closest to the sun
Permafrost Permanently frozen soil, subsoil or other ground deposit
Phenology The recording and study of periodic biologic phenomena (e.g. plant flowering times) in relation to climate, particularly seasonal changes
Photodissociated Molecules split apart by light (e.g. ozone is photodissociated by sunlight)
Photorespiration The oxidation of carbohydrates in plants with the release of carbon dioxide, energy and water during photosynthesis
Photosynthesis Process by which plants use the light energy, carbon dioxide, and water to make oxygen and glucose (a simple sugar)
Photovoltaic systems The use of photovoltaic cells to convert sunlight directly into electricity
Planktic and benthic foraminifera These are single-celled organisms that construct shells. The planktic foraminifera float freely while the benthic foraminifera live in or on sea floor sediments
Plate tectonics The interpretation of the earth’s major structures and processes in terms of the movements of the underlying plates of lithosphere acting as rigid slabs ‘floating’ on the asthenoshphere (mantle) below
Pleistocene Geological epoch that refers to the last two million years, the time of the last great ice ages
Plucking Process of glacial erosion by which blocks of rock are loosened, detached, and borne away from bedrock as water freezes in fissures
Plunge pool Pool at the base of a waterfall formed by the erosive action of the falling water and the rocks carried by that water
Polar climate Climate at latitudes greater than 66o characterized by an annual average temperature of under 10oC
Polar Jet Stream Upper air (about 12 km altitude) winds found between 40o and 60o latitude at speeds usually greater than 90km/hr (and up to 400 km/hr)
ppm Parts per million
Precession Earth’s slow wobble as it spins on axis
Precipitation Products of condensation in the atmosphere, including rain, sleet, snow, hail, dew, and hoar frost
Progradation The building of strata from sediment in a seaward direction due to rising sea levels

 

-Q-

Quadruped A four footed animal. i,e, quadrupedal

 

-R-

Radiation The emission of energy in the form of waves or rays
Radiative forcing A change in the radiation balance due to changes in solar radiation or in the environment. A positive forcing tends to warm the atmosphere. It may be expressed in C˚/wm2
Rapids Small waterfalls and turbulent water along a stretch of river
Refreezing The melting and subsequent refreezing that takes place between two blocks of ice as pressure is applied then released
Relief (Orographic) Precipitation Precipitation caused when warm, moist air follows the higher contours of a landform. Air cools as it rises and water vapour condenses and drops
Riparian A term used in describing the natural banks of a water course
Rodinia Name given to the first super continent in the Late Proterozoic era. It broke into four major areas Gondwana, Laurentia, Siberia (just south of the equator) and Baltica

 

-S-

Salinization The accumulation of natural salts in a soil, often the result of irrigation in the water table
Scenario A hypothetical or predicted sequence of events
Sea-ice dynamics Forces affecting the motion of pack ice, mainly wind and water motion
Sedimentary rock Rock made of layers of eroded sediment put under tremendous pressure at the bottom of seas and oceans
Semi-permeable membranes (selectively permeable membrane) A membrane which will allow only certain molecules or ions to pass through it
Silviculture The care and cultivation of forests
Solar radiation Energy from the sun traveling in light rays
SST Sea surface temperature
Stade Short period of time (less than 10,000 years) characterized by climatic conditions associated with maximum glacial extent
Stratified drift Sediments deposited by glacial meltwater that are sorted and layered. A major subdivision of glacial drift that includes rivers, lakes, and marine deposits
Stratosphere The zone of the atmosphere which lies above the troposphere (from 10-15 km to about 50 km up)
Stream capacity The maximum amount of sediment a stream can carry with a given discharge
Striation The process in which scratches and grooves are made by glacial ice scraping over rocks. It is the rock particles carried by the ice that cause the scratches. The direction of the scratches (striae) indicated the direction of the glacier’s advance
Subduction The process of one lithospheric plate descending under an adjacent plate
Sublimation The direct change of a material from a solid state to a gas state without turning to liquid in between
Sustainable A practice capable of being continued indefinitely

 

-T-

Tectonic displacements The vertical or horizontal shifting of land masses due to forces beneath the Earth’s crust
Temperate climate Climate typical of the mid-latitudes, with neither exceptionally high (tropical) nor low (polar) temperatures and precipitation.  May be either wet (maritime) or dry (continental)
Terrestrial radiation The emission of heat energy from the Earth’s surface and atmosphere into space
Thermohaline The term used in relating to the density of sea water which is determined by temperature and salt content
Thermohaline circulation The movement of ocean water due to differences in density
Tidewater glacier Glacier which terminates in ocean water. The changing sea levels due to tides may accelerate the calving of glaciers
Till (or glacial till) Rock, sand, and fine-grained clay deposited by glaciers
Tillage The cultivation of land for crops
Tillite Sedimentary rock composed of till. Generally considered evidence of pre-Pleistocene glaciations, but identification (compared to landslide debris, for example) is difficult
Tornado Violent, localized storm with powerful funnel clouds that create much damage
Tropical Low latitude (less than 20o latitude) areas characterized by high temperatures and high precipitation. At high elevations, however, tropical mountains may be both cold and relatively dry
Tropopause The boundary between the troposphere and stratosphere varying in altitude from approximately 8 km at the poles to 18 km at the poles
Troposphere Lowest part of the atmosphere, from the ground or ocean surface to about 10-15 km
Trough (or “U-shaped valley”) Steep-walled, (though rarely vertical), and broad-floored. Its presence indicates former mountain glaciation
Typhoon A tropical storm occurring in the western Pacific or Indian Ocean. It is the same as a hurricane

 

-U-

Ultraviolet Short wavelength beyond the visible spectrum at the violet end of the spectrum
UV radiation (A, B, and C) Radiation with wavelengths between those of visible light and those with x-rays. UVA (380-315 nm) are long wave; UVB (315-280 nm) are medium wave; and UVC (280-10 nm) are short wave

 

-V-

Variables A measurable factor, characteristic, or attribute of a system

 

-W-

Weather Meteorological conditions experienced over a short period of time
Weathering Disintegration of rocks caused by physical and chemical forces and processes
Westerlies Prevailing planetary winds in temperate latitudes

 

-Y-

YBP Years before present

 

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