by Loren G. Edelstein | August 01, 2006

The green movement comes with a language all its own. Following is a glossary of terms gleaned from a listing provided by the Natural Resources Defense Council (

Alternative fuels. Transportation fuels other than gasoline or diesel. Includes natural gas, methanol and electricity.

Biodegradable. Waste material composed primarily of naturally occurring constituent parts, able to be broken down and absorbed into the ecosystem.

Carbon dioxide. A naturally occurring greenhouse gas in the atmosphere, concentrations of which have increased (from 280 parts per million in preindustrial times to more than 350 parts per million today) as a result of humans’ burning of coal, oil, natural gas and organic matter.

Carbon tax. A charge on fossil fuels (coal, oil, natural gas) based on their carbon content. When burned, the carbon in these fuels becomes carbon dioxide in the atmosphere, the chief greenhouse gas.

Clean fuel. Fuels that have lower emissions than conventional gasoline and diesel. Refers to alternative fuels as well as to reformulated gasoline and diesel.

Compost. The process whereby organic wastes, including food, paper and yard wastes, decompose naturally, resulting in a product rich in minerals and ideal for gardening and farming.

Emissions cap. A limit on the amount of greenhouse gases that a company or country can legally emit.

Fossil fuel. A fuel, such as coal, oil and natural gas, produced by the decomposition of ancient (fossilized) plants and animals.

Gas. Natural gas, used as fuel.

Gasoline. Petroleum fuel, used to power cars, trucks, lawn mowers, etc.

Global warming. An increase in the average temperature of the earth’s surface.

Green design. A design, usually architectural, conforming to environmentally sound principles of building, material and energy use. A green building, for example, might make use of solar panels, skylights and recycled building materials.

Greenhouse effect. The process that raises the temperature of air in the lower atmosphere due to heat trapped by greenhouse gases, such as carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and ozone.

Ozone. A naturally occurring, highly reactive gas comprising triatomic oxygen formed by recombination of oxygen in the presence of ultraviolet radiation. This gas builds up in the lower atmosphere as smog, while in the upper atmosphere it forms a protective layer that shields the earth from excessive exposure to damaging ultraviolet radiation.

Ozone depletion. The reduction of the protective layer of ozone in the upper atmosphere by chemical pollution.

Renewable energy. Energy resources such as wind power or solar energy that can keep producing indefinitely without being depleted.

Sustainable communities. Communities capable of maintaining their present levels of growth without damaging effects.

Toxic waste. Garbage or waste that can injure, poison or harm living things and is sometimes life-threatening.

Zero-emission vehicles. Vehicles (usually powered by electricity) with no direct emissions from tailpipes or fuel evaporation.

The Natural Resources Defense Council( is an environmental action organization based in Washington, D.C.