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Sea-level rise is caused by adding mass (water) and heat to the ocean. The Antarctic ice sheet represents a potentially large source of water. Knowing the speed and direction (velocity) at which the Antarctic ice sheet is flowing to the ocean is…

A gaseous layer that envelops the Earth and most other planets in the solar system. Earth, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan (Saturn's largest satellite) are all known to possess substantial atmospheres that are held by the…

A scientific discipline concerned with the chemical composition of the Earth's atmosphere. Topics falling within the field include the emission, transport, and deposition of atmospheric chemical species; the rates and mechanisms of chemical…

It has been a long-held belief that, as a result of hunting habits, early humans were partly or even primarily responsible for the decline and eventual extinction of most of the largest mammalian species that inhabited ancient Africa. These large…

The scientific study of climate. Climate is the expected mean and variability of the weather conditions for a particular location, season, and time of day. The climate is often described in terms of the mean values of meteorological variables such…

A brown to black combustible carbonaceous sedimentary rock that is mined and used primarily as a fuel. Coal originated by accumulation and subsequent physical and chemical alteration of plant material over about 300 million years, and contains at…

The concept that the world's continents once formed part of a single mass and have since drifted into their present positions.The fundamental concept is that not only have the continents drifted, but the continents are merely parts of thicker…

The response of corals to environmental stress in which they eject the single-cell algae that live within the transparent coral tissue, making the white coral skeleton visible. Corals (Fig. 1) are animals that live in a partnership (symbiosis) with…

Trees provide substantial benefits to the environment. In addition to improving air quality, reducing stormwater runoff, serving as a wildlife habitat, and sequestering carbon by absorbing carbon dioxide, trees also cool the atmosphere through shade…