Non-renewable energy resources, such as fossil fuels and nuclear energy, are finite power sources that currently underpin global industrial society. Nature cannot replace these resources at a rate comparable to human consumption. Finitude is defined by three factors: the immense time required for their creation, the exponential speed of modern human use, and the economic barriers to accessing the full supply.
The Requirement of Geological Time
Fossil fuels like oil, coal, and natural gas are considered finite because their formation is the result of slow, rare geological processes spanning millions of years. Petroleum and natural gas originated primarily from the buried remains of microscopic marine organisms, such as plankton, that died and settled on the seafloor in anoxic conditions. Over time, these organic materials mixed with sediment and were buried under heavy layers of rock, subjecting them to intense heat and pressure.
This process transforms the organic matter into a waxy substance called kerogen, which is then chemically altered into liquid and gaseous hydrocarbons within a specific temperature range known as the “oil window.” Much of the oil currently being extracted was formed during the Mesozoic era, between 252 and 66 million years ago. Similarly, coal deposits were formed from ancient swamp vegetation during the Carboniferous period, roughly 300 million years ago. The time scale for this natural replenishment is so vast that the rate of new formation is effectively zero when measured against a human lifespan.
The Speed of Human Consumption
The second reason for finitude is the massive mismatch between the pace of geological creation and the rate of modern industrial consumption. The fuels that took hundreds of millions of years to accumulate are now being extracted and burned within a span of just a few centuries. The Industrial Revolution marked the beginning of a rapid, widespread reliance on these dense energy sources, accelerating the consumption rate far beyond any natural replenishment cycle.
Global fossil fuel consumption has increased dramatically, growing eightfold since 1950 alone. This exponential rise in demand, driven by population growth and technological advancement, means that a geological process requiring eons is being depleted in mere decades. Humans are currently consuming fossil fuels at a rate millions of times faster than nature can create them.
Economic and Accessible Reserves
The practical limit of non-renewable resources is not the total physical amount in the Earth, but the portion that is economically and technologically accessible. Scientists distinguish between the total resource base (all material physically present) and proven reserves. Proven reserves are quantities that can be recovered profitably with existing technology and under current economic conditions. The total resource base includes deposits that are too difficult, too deep, or too costly to extract.
As the most easily accessible reservoirs are depleted, the remaining deposits become progressively more expensive to retrieve, requiring advanced and costly techniques. This increasing difficulty and cost effectively define the finitude for society, as the energy required to extract the fuel eventually approaches the energy gained from the fuel itself. Therefore, the usable supply runs out long before the last molecule of the resource is physically gone from the Earth.