When will fossil fuels run out?

Fossil fuels are hundreds of millions of years old, but in the last 200 years consumption has increased rapidly, leaving fossil fuel reserves depleted and climate change seriously impacted. Reserves are becoming harder to locate, and resources won’t last forever – here’s when fossil fuels could run out.

What are fossil fuels?

Fossil fuels are biological materials containing hydrocarbon, which can be burned and used as a source of energy. They’re found in the Earth’s crust, so we have to drill into the earth to extract them.

Fossil fuels developed billions of years ago, when dead organic matter became buried at the bottom of the sea and altered as a result of anaerobic digestion. Oil deposits in the North Sea are around 150 million years old, while much of Britain’s coal began to form over 300 million years ago.

While we probably used fossil fuels as far back as the Iron Age, it wasn’t until the Industrial Revolution that wide-scale extraction started. It completely transformed the way humanity lived and worked, allowing us to power our homes, businesses and machines with coal, oil and gas.

Why are fossil fuels bad?

We only have a finite supply of fossil fuels. The amount we use now simply isn’t sustainable, and the problem is getting worse as the global population increases. The limited resources in the ground aren’t even the biggest problem – there are plenty of downsides to plundering the earth for coal, gas and oil:

  • Carbon emissions. Global carbon emissions from fossil fuels accounts for 90% of all emissions from human activity. And while UK carbon emissions are dropping, global fossil fuel emissions are increasing and global temperatures are rising.
  • Air pollution. The burning of fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere, which pollutes the air we breathe. Air pollution in cities has been linked to an increase in respiratory diseases, like asthma, particularly in young children and the elderly, along with shortened life expectancy.
  • Ocean pollution. Carbon dioxide dissolves into the sea, causing acidification which affects the life cycles of marine organisms. Our oceans absorb heat created from fossil fuel emissions, causing temperatures to rise and coral reefs to bleach and die.
  • Habitat destruction. Vast amounts of land are decimated to provide space for drilling wells, pipelines, and processing facilities used in oil and gas drilling operations. Habitat disruption and noise from drilling are some of the biggest threats to wildlife populations across the globe.
  • Transporting fossil fuels. Aside from the carbon emissions caused by burning fossil fuels, there’s a huge environmental cost to transporting them. Diesel fumes from transportation add to CO2 emissions, oil spills threaten marine life, and flammable natural gas leaks have led to hundreds of human casualties in recent years.

Fossil fuels, as the name suggests, are very old. North Sea oil deposits are around 150 million years old, whilst much of Britain’s coal began to form over 300 million years ago. Although humans probably used fossil fuels in ancient times, as far back as the Iron Age, it was the Industrial Revolution that led to their wide-scale extraction.

And in the very short period of time since then – just over 200 years – we’ve consumed an incredible amount of them, leaving fossil fuels all but gone and the climate seriously impacted.

Fossil fuels are an incredibly dense form of energy, and they took millions of years to become so. And when they’re gone, they’re gone pretty much forever.

How long will fossil fuels last?

Global fossil fuel consumption is on the rise, and new reserves are becoming harder to find. Those that are discovered are significantly smaller than the ones that have been found in the past. Oil reserves are a good example: 16 of the 20 largest oil fields in the world have reached peak level production – they’re simply too small to keep up with global demand.

In order to keep average global temperature increases below 1.5°C, we need to leave up to 80% of our fossil fuel reserves in the ground – but globally, our reliance on fossil fuels is increasing. Here’s how long current fossil fuel reserves could last:

Graph showing future energy reserves for coal, gas and oil

*Graph showing future energy reserves for coal, gas and oil.


Globally, we currently consume the equivalent of over 11 billion tonnes of oil from fossil fuels every year. Crude oil reserves are vanishing at a rate of more than 4 billion tonnes a year – so if we carry on as we are, our known oil deposits could run out in just over 53 years.


If we increase gas production to fill the energy gap left by oil, our known gas reserves only give us just 52 years left.


Although it’s often claimed that we have enough coal to last hundreds of years, this doesn’t take into account the need for increased production if we run out of oil and gas.

If we step up production to make up for depleted oil and gas reserves, our known coal deposits could be gone in 150 years.

Are there any advantages to fossil fuels?

While there are some benefits to fossil fuel production, the adverse effects on the environment and overall public health far outweigh them. But governments and businesses around the world have placed short term gain from investing in fossil fuels above the longer term benefits of renewable energy.

What about fracking?

Fracking involves the extraction of shale gas by drilling into the Earth and pumping boreholes full of a high pressure water mixture. Shale gas is a type of fossil fuel, which means supplies will eventually run out.

It’s unclear how much shale is available at fracking sites in the UK but, because current activity is still in the exploratory phase, virtually no planning permission is needed to begin drilling. Works have been halted in the UK due to earthquakes and seismic activity, but the government still provides backing to fracking companies, despite widespread public opposition.

You can find out more about fracking and the environmental risks posed by fracking activity here.

The green alternative

Unlike fossil fuels, green energy made from wind and solar power is sustainable, because its generated by resources that won’t run out. Plus, it provides a way to fight climate change by reducing and even offsetting carbon emissions.

For example, the energy payback for solar power technology  is just two years. That means it only takes two years for a solar park to make the same amount of energy used in its manufacture and installation. And after that, it can provide decades of clean energy that’s better for the planet.

If we have any hope of fighting climate change and protecting the future of our planet, we need to ditch fossil fuels and start investing in renewable sources of energy. Find out how you can switch to green energy quickly and easily, and start building a greener Britain.


All fossil fuel reserve and consumption data from CIA World Factbook and Statista.

Al Gore

"As more and more people understand what's at stake, they become a part of the solution, and share both in the challenges and opportunities presented by the climate crises."

Al Gore

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