When Will We Run Out of Oil, and What Happens Then?

Naturally, we can't tap and drain an entire planet's worth of oil from a single well. Countless oil wells pox Earth's surface: some active, some long-drained. Each oil well follows a production bell curve, with output rising, stabilizing and then declining to nothing over a period of years.

This is called the Hubbert Curve, proposed in 1956 by Shell geologist Marion King Hubbert.

Hubbert also extrapolated his curve to global oil production. Oil companies discover the large, easily exploited oil fields first and then move onto smaller, deeper oil fields when the large ones decline.

New technology also continues to make previously unexploited oil deposits viable fossil fuel reserves. The overall curve predicts that global production will rise, peak and then fall off.

Before this gradual downfall begins, however, we'll reach a point known as peak oil. Imagine a carafe filled with coffee. Now imagine pouring cup after cup without effort until the stream of java begins to trickle.

Eventually you even have to severely tilt the carafe in order to drain the dredges. Peak oil is that last full and flowing cup before the final decline begins. Demand continues to grow, while the Earth's nonrenewable oil reserves dwindle.

What peak oil proponents missed, however, was that both the supply of oil and demand for oil would change significantly during the 21st century. Technological advances in oil extraction methods, like fracking, which releases shale oil, means that the supply of oil has actually increased in the United States [source: EIA].

At the same time, we now have a much better understanding of the impact burning fossil fuels has on climate change. Global warming has led to high demand for renewable energy sources and alternative fuels.

The International Energy Agency (IEA) estimates that we could reach "peak demand" for oil in 2028, due to factors including rising prices and the increased number of electric cars on the road [source: IEA].

In its 2021 International Energy Outlook, the U.S. Energy Information Administration (EIA) projected that the world's oil supply will continue to meet the growing global energy demand until at least 2050 [source: EIA]. Beyond 2050, "there is substantial uncertainty about the levels of future liquid fuels supply and demand," according to EIA [source: EIA].

When Russia invaded Ukraine in February 2022, nations that previously relied on Russia for oil got a sense of what it might be like to live with a reduced supply of petroleum. Fuel prices skyrocketed, and many areas faced power cuts. In Sri Lanka, schools were closed as extremely limited fuel supplies went to keep hospitals open [source: Reuters].

More optimistic views of this inevitable post-peak world involve a lot more preparation. Basically, the impact of oil shortages can be lessened by decreasing our reliance on fossil fuels.

Alternative energy sources and renewable biofuels play a crucial role in these outlooks. Some commentators even go so far as to see eventual oil shortfalls as a stabilizing factor in world politics [source: Drezner].

The writing is on the wall. Global oil supply can't meet the current rate of global oil demand forever, necessitating new energy sources and usage practices. Even if technology allowed us to harvest every last drop of oil in the planet (thereby increasing scarcity), rising prices and climate impacts would necessitate widespread change long before we actually ran out of oil.