Natural resources are those elements of the environment that are considered valuable to humans. These can be raw materials, such as trees for lumber and ore for manufacturing, or things that are directly consumed, such as groundwater to drink and animals to eat. The word "natural" means that there has been no modification by humans. A "resource" is something that is necessary for growth and reproduction. Natural resources can be divided into three categories: perpetual resources, like the Sun; potentially renewable resources, like forests; and nonrenewable resources, like fossil fuels.

While a resource can be something that is necessary for an animal as well as a human, the term "natural resource" is always used in the human context. The use of this term has increased with the growing awareness of the need to manage the use of these resources to ensure their existence in the future...