- Heat produced deep in the Earth from the natural decay of radioactive elements.
- Biological diversity that encompasses the genetic variety among individuals within a single species.
- Warming of the earth’ surface and the lower layers of atmosphere that tends to increase with greater atmospheric carbon dioxide concentration. Solar radiation is converted into heat in a process involving selective transmission of short wave solar radiation by the atmosphere, its absorption by the earth’ surface, and reradiation as infrared that is absorbed and partly reradiated back to the surface by carbon dioxide and water vapor in the air.
- Gases, including water vapor, carbon dioxide, methane, nitrous oxide, chlorophluorocarbons, and ozone, that insulate the earth, letting sunlight through the earth’s surface while trapping outgoing radiation.
- The supply of fresh water under the Earth’s surface. Groundwater is stored in porous layers of underground rock called auifers. Compare surface water.
Ground water “mining”
- Withdrawal of ground water at a rate in excess of its natural or artificial recharge.
- The erosion process whereby water accumulates in narrow channels and overshort period removes the soil from this narrow area to considerable depths, ranging from 1 to 90 m.