Global Climate Change: Glossary

Carbon dioxide

The chemical formula for carbon dioxide is CO2. The formula indicates that carbon dioxide is composed of one atom of carbon and two atoms of oxygen. Carbon dioxide makes up only about 33/1000 of one percent of the air but its presence and concentration is extremely important to the balance of life on earth. Carbon dioxide is a waste product of animal metabolism and is exhaled in breathing. It is also essential for the growth of plant life. The carbon dioxide link between plants and animals accounts for one of the natural cycles that establishes interdependency between plants and animals. The gas is important climatically because it absorbs heat and creates an insulating blanket for the earth thus affecting temperatures near the earth's surface.

Cumuliform clouds

Cumuliform clouds are flat-based, massive, globular clouds. They are often higher than they are wide. A cumulus cloud is an example of a cumuliform cloud. Simple fair weather cumulus clouds are snow-white and cotton like with rounded tops and flattened bases. These small cumulus clouds may grow larger and denser indicating strong rising air currents carrying moist air rapidly to higher levels. Eventually another cumuliform cloud called a cumulonimbus cloud or thunderhead may develop bring violent rain, hail, wind gusts, thunder and lightening.

Electromagnetic radiation spectrum

The spectrum is the entire range of wavelengths that make up electromagnetic radiation. The electromagnetic radiation spectrum includes X rays, ultraviolet radiation, visible light, infrared radiation, heat, microwaves and radio waves. Most of the wavelength's in the electromagnetic radiation spectrum are so small that they cannot be conveniently measured by familiar units such as inches or centimeters. Scientists use the micron to describe electromagnetic radiation. The micro is on ten-thousandths of a centimeter (0.0001 centimeter) or about four-hundred thousandths of an inch (0.0004).

X rays and gamma rays are among the shortest wave lengths in the electromagnetic spectrum. X rays and gamma rays are shorter than one hundredth (.01) of a micron. Heat rays are on the longer end of the electromagnetic spectrum. Heat wavelengths range from three to three thousand (3 - 3000) microns. Radio waves can be several feet to several miles long.

Feedback mechanism

A feedback mechanism is a process in which the factors that produce a result are modified by the result. In a positive feedback process the factors are strengthened by the result. Positive feedback mechanisms are destabilizing to a system and thus are generally undesirable. In a negative feedback process the factors are weakened by the result. Negative feedback mechanisms are stabilizing to a system and thus are generally desirable.

A positive feedback theory related to the greenhouse effect holds that increasing carbon dioxide, a greenhouse gas, will result in raising ocean temperatures. Increased ocean temperatures will increase evaporation thus placing more water vapor, also a greenhouse gas, in the atmosphere. The increased presence of greenhouse gases will enhance or strengthen the greenhouse effect thus increasing temperatures.

A negative feedback theory related to the greenhouse effect holds that the increased evaporation would create more clouds that would reflect more solar energy than they retain. In this case the greenhouse effect would be weakened and earth's temperatures would cool.

Hydrologic cycle

The hydrologic cycle is the continuing cycle of water evaporating, condensing and precipitating.

Tracing the possible movements of one droplet of water through the hydrologic cycle may demonstrate the complexity of the cycle. The geographical position of the water droplet may continually change. The droplet may evaporate from the ocean. While it is water vapor, winds may move it over the surface of the planet. When the water vapor condenses in a cloud, the droplet may continue to move over the planet carried by wind currents. During this stage of the hydrologic cycle the droplet may be carried to such heights that it freezes. The droplet may eventually return to the earth in the form of rain or frozen precipitation. The droplet may find its way to a soil or rock surface. At that point it may run off into a stream or other body of water and eventually go back to the ocean.

The path described above is only one of a number of possible circuits that the droplet may follow in the hydrologic cycle. Water may evaporate from any body of water or from the soil. Water may become part of the ground water. There are a number of permutations but the basic processes of the hydrologic cycle are evaporation, condensation and precipitation.

Ice cores

Ice cores are long cylindrical ice samples obtained by boring through ice that results from the compacting of many annual layers of snow. Over many years snow forms layers similar to rock strata. Scientists can determine annual snowfall because each year's snow forms a layer.

Infrared radiation

Electromagnetic radiation, which is longer than red visible light is, called infrared radiation. The wavelength of red visible light ranges from sixty-five hundredths to seventy (.65-.70) hundredths microns. Infrared radiation is synonymous with heat.

Mineralogical characteristics

A mineral is a natural substance that is crystalline, inorganic and has a unique chemical structure. A rock may be make up of one or more minerals. A substance may have a chemical name, a rock name and also a mineral name. Limestone is a rock. Its chemical name is calcium carbonate, which indicates that it is composed of the chemical elements of calcium., carbon, and oxygen. Its mineral name is calcite. Most rocks are made up of more than one mineral.

Mineralogical characteristics include hardness, reactivity with chemicals, color, luster, and density, crystal shape and crystal size.

160/180

O is the chemical symbol for oxygen. Oxygen is the common gas needed by animals for breathing. Oxygen makes up 21% or about one-fifth of the air by volume. The chemical reactions of oxygen are responsible for rusting iron, burning fuel, and the biological processes that produce heat and energy in animals.

The smallest particle of oxygen is an atom. However not all oxygen atoms are the same. Atoms are made up of even smaller particles. The most prominent particles in atoms are protons, neutrons and electrons. All oxygen atoms have eight (8) protons and eight (8) electrons, but the number of neutrons varies. Atoms of oxygen with different numbers of neutrons are call isotopes of oxygen. 160 is the chemical symbol for an isotope of oxygen that has eight (8) neutrons. 180 is a chemical symbol for an isotope of oxygen that has ten (10) neutrons.

Oxygen 16, with fewer subatomic particles, has less mass than oxygen 18 so it evaporates from ocean water more readily. During cold glacial periods the oxygen 16 is heavily concentrated in precipitation and in the glacial ice that may form from the precipitation. During those cold periods the oxygen 18 is heavily concentrated in the ocean water. During warmer interglacial periods, the glaciers are melting and the oxygen 16 atoms are returning to the ocean water. Also more oxygen 18 evaporates during warm periods than during cold periods.

160/180 indicates a mathematical ration calculated by dividing the number of oxygen 16 isotopes by the number of oxygen 18 isotopes. That number will change as the air temperature changes. Scientists can calculate that number for past ages by analyzing sample of ice that froze thousands of years ago. The ratio is also reflected in the shells of organisms that formed during a specific period.

Ozone

Ozone is one form of oxygen. The chemical formula O3 represents ozone. A molecule of ozone is formed by the chemical combination of three oxygen atoms. The most common form of oxygen is O2.

In the stratosphere ozone creates a protective layer which filters ultraviolet light to the earth. Ozone near the earth's surface, on the other hand, is a threat to human health. It is a respiratory irritant and a factor in the creation of smog.

Paleobotanical characteristics

Paleobotany is the study of early, ancient, or primitive plants. Scientists can study ancient plants by observing fossils of those plants or by examining residue left by the plant's decomposition.

Photosynthesis

Photosynthesis is a complex chemical process that is unique to green plants. Chlorophyll-containing cells in green plants convert light to chemical energy and synthesize carbohydrates from carbon dioxide and water. Plants release oxygen during photosynthesis.

Pressure gradients in ocean water

The pressure which water exerts equally in all directions increases with increasing depth. The rate of change in the water pressure is a pressure gradient. Pressure gradients in ocean water contribute to the formation of ocean currents. The less pressurized surface water is moved by winds over the more pressurized deeper water. Other factors that contribute to ocean currents are water temperature and density.

Solar radiation

The sun emits a mixture of the total spectrum of electromagnetic radiation. Heat and light are electromagnetic radiation emitted by the sun. The sun also emits particles that are released when atoms in the sun disintegrate. All of the sun's emissions are called solar radiation.

Specific heat

When the same amount of heat is supplied to equal masses of water and soil, the soil temperature will rise much more rapidly than the water. Water is said to have a high specific heat while soil has a low specific heat.

Scientist define specific heat as the number of calories needed to raise the temperature of one gram of a substance on degree Celsius.

Stratiform clouds

Stratiform clouds form blanket-like layers. These clouds could not exist with strong vertical air movements. Stratiform clouds may indicate that air is moving in layers. Air within a layer may be turbulent, but one layer of air may slide over another layer. Stratiform clouds form at all elevations. Cirrostratus is a high cloud that commonly causes a halo-like effect around the sun. Altrostraus is a middle level cloud. It is uniform, thick, gray and frequently produces precipitation. Stratocumuli are low clouds that often form during the clearing period following a storm.

Stratigraphic relationships

Stratigraphy is the arrangement of rocks in layers or strata. Scientists can find information about the past by studying rock strata.

Sediment from the sea may form a layer of rock. An erupting volcano may cover the sedimentary rock with a layer of lava. Pressure exerted on base layers by surface layers may change the characteristics of the base layers. An earthquake may cause folding of the layers. Rock strata can yield information about their origin and history.

Southern oscillation

The southern oscillation is the seesaw pattern of atmospheric pressure change that occurs between the eastern and western Pacific Ocean. These pressure changes alter the directions in which the trade winds blow. Indicators of this wind shift are warmer surface-water temperature (El Nino) or colder surface-water temperature (La Nina). The interaction of these events can cause extreme weather events in many parts of the world.

Till

Till is an unsorted mix of clay, sand, boulders, gravel and other debris deposited by a glacier as it melts.

Tree rings

Examination of a cross section of a trunk reveals concentric pattern in the wood called tree rings. A year's growth of the tree is usually represented by a light ring and a dark ring. During wet warm periods the tree grows more rapidly and the wood formed in light colored. During cold periods the tree grows very slowly. During a drought period the tree grows slowly. Comparison of annual tree tings for one tree as well as for many trees reveals information about past climates.

Ultraviolet radiation

Violet light has the shortest wavelength of any visible light in the electromagnetic radiation spectrum. Wavelengths of violet light range from forty to forty-three (.40 - .43) hundredths microns. Electromagnetic radiation that is shorter than violet light but longer than X rays is called ultraviolet radiation.

Visible spectrum

The visible spectrum is that part of the electromagnetic spectrum that includes wavelengths of violet, blue, green, yellow, orange, and red light. The wavelength of visible light ranges from four tenths to seven tenths (/4-/7) of a micron.

Wavelength

To define wavelength it is useful to visualize a rock falling into water. The impact produces a disturbance that travels through the water from the point at which the rock was dropped. The distance between the crests or high points of the disturbance is the wavelength of the wave.

A toy "slinky" or a long spring can also demonstrate wavelength. A wave or disturbance can move through the spring. The wave can be seen as contractions and extensions of the spring. In this case the wavelength is the distance between two contractions or two extensions.

Wavelength also applies to electromagnetic radiation. Electromagnetic radiation travels as a disturbance or wave-like motion through space.