出典:Wikipedia
出典:『Wikipedia』 (2011/06/30 11:15 UTC 版)
A non-renewable resource is a natural resource which cannot be produced, grown, generated, or used on a scale which can sustain its consumption rate, once used there is no more remaining. These resources often exist in a fixed amount and are consumed much faster than nature can create them. Fossil fuels (such as coal, petroleum and natural gas) and nuclear power (uranium) are examples. In contrast, resources such as timber (when harvested sustainably) or metals (which can be recycled) are considered renewable resources.