A natural resource is a renewable resource if it is replaced by natural processes and if replenished with the passage of time. Renewable resources are part of our natural environment and form our eco-system.
In 1962, within a report to the committee on natural resources which was forwarded to the President of the United States, Paul Weiss defined Renewable Resources as: "The total range of living organisms providing man with food, fibers, drugs, etc...".
Renewable resources are endangered by industrial developments and growth. They must be carefully managed to avoid exceeding the natural world's capacity to replenish them. A life cycle assessment provides a systematic means of evaluating renewability. This is a matter of sustainability in the natural environment.
Solar radiation, tides, winds, geothermal, biomass and other natural elements are renewable resources of energy now called renewable energies.