Exhaustible resources, or nonrenewable resources, include fossil fuels, mineral ores and uranium. Use of these natural resources leads to their depletion. Inexhaustible resources include solar, wind and hydroelectric power, which naturally replenish, or timber and corn, which can be replenished through proper management.
While humans depend heavily on exhaustible resources, good management can extend the amount of time that they last. Conservation, recycling and phasing in inexhaustible resources to take the place of exhaustible ones are all important. Conservation involves both using less of the dwindling supply of exhaustible resources and finding ways to reduce waste. For example, a home that is well-insulated uses less exhaustible energy to heat and cool rooms.
Recycling is another way to extend the use of exhaustible resources. To be efficient, the recycling process should take into account the amount of nonrenewable energy expended on producing and recycling items in addition to the material itself. For example, while timber is a renewable resource, the energy expended to recycle wood may be less than that expended to cut and transport trees.
Ultimately, all exhaustible resources run out. The solution to humanity's energy problem involves developing and using techniques for efficiently harnessing and making use of inexhaustible resources.