Atmosphere: At·mo·sphere ['at-m&-"sfir]. The mixture of gases surrounding the Earth. The Earth's atmosphere consists of about 79.1% nitrogen (by volume), 20.9% oxygen, 0.036% carbon dioxide and trace amounts of other gases. The atmosphere can be divided into a number of layers according to its mixing or chemical characteristics, generally determined by temperature. The layer nearest the Earth is the troposphere, which reaches up to an altitude of about 8 km (about 5 miles) in the polar regions and up to 17 km (nearly 11 miles) above the equator. The stratosphere reaches to an altitude of about 50 km (31 miles) and lies above the troposphere. The mesosphere extends up to 80-90 km and is above the stratosphere, and finally, the thermosphere, or ionosphere, gradually diminishes and forms a fuzzy border with outer space. There is very little mixing of gases between layers.
Barometric Pressure: Bar·o·me·tric Pres·sure ["bar-&-'me-trik 'pre-sh&r]. The pressure of the atmosphere (usually expressed in terms of the height of a column of mercury).
Barricade: Bar·ri·cade ['bar-&-"kAd]. An obstruction or rampart constructed to block the advance of the ocean.
Climate: Cli·mate ['klI-m&t]. The average weather (usually taken over a 30-year time period) for a particular region and time period. Climate is not the same as weather, but rather, it is the average pattern of weather for a particular region. Weather describes the short-term state of the atmosphere. Climatic elements include precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and hail storms, and other measures of the weather.
Climate System: Cli·mate Sys·tem ['klI-m&t 'sis-t&m]. The atmosphere, the oceans, the biosphere, the cryosphere, and the geosphere, together make up the climate system.
Climatologist: Cli·ma·to·lo·gist ["klI-m&-'tä-l&-jist]. A person who studies climate.
Concentration: Con·cen·tra·tion ["kän(t)-s&n-'trA-sh&n]. The amount of a component in a given area or volume. In this case, a measurement of how much of a particular gas is in the atmosphere compared to all of the gases in the atmosphere.
Deforestation: De·for·es·ta·tion [(")dE-"for-&-'stA-sh&n]. The change of forested lands to non-forest uses. This is often cited as one of the major causes of the enhanced greenhouse effect for two reasons: 1) trees that are burned or decompose release carbon dioxide; and, 2) trees that are cut no longer remove carbon dioxide from the atmosphere.
ºF: ºF means and should be read as De·grees Fahr·en·heit [di-'grEs 'far-&n-"hIt]. Units for measuring temperature. Fahrenheit units represent a thermometric scale on which under standard atmospheric pressure the boiling point of water is at 212 degrees above the zero of the scale, the freezing point is at 32 degrees above zero, and the zero point approximates the temperature produced by mixing equal quantities by weight of snow and common salt.
Drought: Drought ['draut]. A period of abnormally dry weather long enough to cause serious shortages of water for agriculture and other needs in the affected area.
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: E·co·sys·tem ["E-k&-"sis-t&m]. The complex of a community of organisms and the community's environment functioning as an ecological unit.
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.
Fossil Fuel: Fos·sil Fu·el ['fä-s&l 'fyü(-&)l]. A general term for a fuel that is formed in the Earth from plant or animal remains, including coal, oil, natural gas, oil shales, and tar sands.
Glacier: Gla·cier ['glA-sh&r]. A very large body of ice moving slowly down a slope or valley or spreading outward on a land surface.
Greenhouse Effect: Green·house Ef·fect ['grEn-"haus E-'fekt]. The effect produced as greenhouse gases allow incoming solar radiation to pass through the Earth's atmosphere, but prevent most of the outgoing infrared radiation from the surface and lower atmosphere from escaping into outer space. This process occurs naturally and has kept the Earth's temperature about 60 degrees Fahrenheit warmer than it would otherwise be. Current life on Earth could not be sustained without the natural greenhouse effect.
Greenhouse Gas: Green·house Gas ['grEn-"haus 'gas]. Any gas that absorbs infra-red radiation in the atmosphere. Greenhouse gases include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), halogenated fluorocarbons (HCFCs), ozone (O3), perfluorinated carbons (PFCs), and hydrofluorocarbons (HFCs).
Habitat: Ha·bi·tat ['ha-b&-"tat]. The place or environment where a plant or animal naturally or normally lives and grows.
Heat Stress: Heat Stress ['hEt 'stres]. A variety of problems associated with very warm temperatures and high humidity. Heat exhaustion is a condition marked by weakness, nausea, dizziness, and profuse sweating that results from physical exertion in a hot environment. Heat stroke is a condition marked especially by cessation of sweating, extremely high body temperature, and collapse that results from prolonged exposure to high temperature.
Industrial: In·dus·tri·al [in-'d&s-trE-&l]. Relating to industry; in this case, industrial practices refer how products are made and used.
Industrial Revolution: In·dus·tri·al Re·vo·lu·tion [in-'d&s-trE-&l "re-v&-'lü-sh&n]. A rapid major change in an economy marked by the general introduction of power-driven machinery or by an important change in the prevailing types and methods of use of such machines.
Methane: Me·thane ['me-"thAn]. Colorless, odorless, flammable hydrocarbon (CH4) that is a product of decomposition of organic matter and of the carbonization of coal. Methane is one of the greenhouse gas chemical compounds.
Precipitation: Pre·ci·pi·ta·tion [pri-"si-p&-'tA-sh&n]. Rain, hail, mist, sleet, snow or any other moisture that falls to the Earth.
Solar Energy: So·lar En·er·gy ['sO-l&r 'e-n&r-jE]. Also called solar radiation. Energy from the Sun. Also referred to as short-wave radiation. Of importance to the climate system, solar radiation includes ultraviolet radiation, visible radiation, and infrared radiation.
Thermal: Ther·mal ['th&r-m&l]. Thermal properties are dependent on temperature; they are related to, or caused by, heat.
Topography: To·po·gra·phy [t&-'pä-gr&-fE]. The configuration of a surface including its relief and the position of its natural and man-made features. The shape of a surface.
Weather: Wea·ther ['we-[th]&r]. Weather is the specific condition of the atmosphere at a particular place and time. It is measured in terms of such things as wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation. In most places, weather can change from hour-to-hour, day-to-day, and season-to-season. Climate is the average of weather over time and space. A simple way of remembering the difference is that 'climate' is what you expect (e.g., cold winters) and 'weather' is what you get (e.g., a blizzard).