(i) Classification of natural resources based on Renewability:
Renewable resources (Flow resources): The resources which can be renewed along with their exploitation and can be always available for use are known as renewable resources. These resources have natural regeneration and these are inexhaustible. Some examples of renewable resources are forests, air, solar energy etc.
Non-renewable resources (Stock resource): The resources which are present in finite quantities and cannot be renewed along with their exploitation are known as non-renewable resources. If these resources are used in large scale, these will exhausted soon. So these are also known as exhaustible resources. Some examples of such type of resources are coal, minerals, fossil fuels etc.
Cyclic resources: The resources which can be used again and again passing through some processes are known as cyclic resources. An example of cyclic resource may be water.
(ii) Based on Development: Considering their stage of development, natural resources may be classified as:
Potential resources: Potential resources are those that exist in a region and may
be used in the future. For example, petroleum occurs with sedimentary rocks in various regions, but until the time it is actually drilled out and put into use, it remains a potential resource.
Actual resources: Actual resources are those that have been surveyed, and
whose quantity and quality are determined and are being used in present times. The development of an actual resource, such as wood processing, depends upon the technology available and the cost involved.
Reserve resources: The part of an actual resource which can be developed profitably in the future is called a reserve resource.
Stock resources: Stock resources are those that have been surveyed but cannot be used by organisms due to lack of technology. For example: hydrogen.
(iii) Based on Distribution:
Biotic resources: When a resource is living organism or originated from living organisms, it is known as biotic resource i.e., it is obtained from the biosphere. Some examples of such type of resources are coal, mineral oil, forest, etc.
Abiotic resources: When a resource is not derived from living organism, it is termed as abiotic resource i.e., such resources are composed of non living inorganic matter. Some examples of such type of resources are air, land, water. minerals etc.
