Why is oil classified as a non-renewable resource?

Oil is classified as a non-renewable resource because it takes millions of years to form. The process of oil formation involves the slow decomposition of organic material, primarily from ancient marine organisms, under layers of sediment and rock. This geological process occurs over an extensive time scale, typically requiring millions of years for significant reservoirs of oil to develop.

As a result, once we deplete these reserves through extraction and use, they cannot be replaced within a human timeframe. This contrasts with renewable resources, which can be replenished in a much shorter period, such as plants or solar energy. The long formation time is the key factor that categorizes oil as non-renewable.