Glossary

albedo

The proportion of incoming solar radiation reflected back into space either by the Earth's surface or by particles in the atmosphere.

atmosphere

The envelope of gases surrounding a planet, e.g., Earth's atmosphere consists of approximately 80 percent nitrogen and 20 percent oxygen.

calcium carbonate

A colorless or white crystalline compound occurring naturally as the minerals calcite or aragonite in rocks like chalk, limestone, and marble.

carbon dioxide

A molecule consisting of one carbon atom and two oxygen atoms (CO2). Its gas is denser than air.

climate

Average weather conditions of a region, including temperature, precipitation, and winds.

elevation

The height of an object above a particular reference level, usually sea level.

glacier

A permanent body of ice that shows evidence of downslope or outward movement due to the stress of its own weight.

glaciology

The study of glaciers.

global warming

An increase in Earth's average temperature.

ice sheet

A continent-sized mass of glacier ice that overwhelms the underlying topography.

interglacial

A period of warmth separating two major glacial periods.

limestone

A common sedimentary rock consisting mostly of calcium carbonate, predominantly formed from the skeletons of marine organisms, calcareous sand, microorganisms, shell fragments, and coral.

meter

A unit of length in the metric system equal to 3.28 feet.

Northern Hemisphere

The half of Earth north of the equator.

paleoclimate

Past climate.

projection

A forecast about a future situation based on the study of a current situation.