Fossil Fuels: The Facts

We explain the benefits of fossil fuels like coal, oil and gas, as well as their damaging effects on climate change and the environment. We look at how we replace them with renewable energy sources and the difficulties involved.
Coal Mining South Kalimantan Indonesia
Open coal mine in South Kalimantan, Indonesia. Photo: © Dominik Vanyi / Unsplash

What Are Fossil Fuels?

Popularized by climate change, the term “fossil fuels” describes any solid, liquid or gaseous fuel (like coal, peat, crude oil, petroleum or natural gas) that has been formed in the earth from the residues of plants or animals over millions of years.

Fossil fuels are extremely old hydrocarbon compounds that started life up to 600 million years ago. They are the buried remains of energy-rich plant and animal matter that acquired their energy from the sun during photosynthesis. 1

During the period of their formation, the layers of matter are exposed to geological stresses such as high pressure and heat, which results in three main types of fossil fuel: (a) coal, (b) Petroleum (includes crude oil), and (c) natural gas. Less common is peat, a younger form of coal.

Fossil fuel derivatives range from aviation fuel (avgas), kerosene (paraffin) and liquid petroleum gas (propane or butane), to coke and lignite (brown coal). All fossil fuels are non-renewable, which means that supplies are finite and will eventually run out. However, due to pressure from climate scientists to decarbonize the world economy and establish a global carbon budget, as well as concerns about the environmental effects of fossil fuels, it is likely that a significant proportion of all hydrocarbon fuels will never be burned.

That said, given the latest statistics on energy consumption, population growth and the consequent “energy gap”, the idea that we can phase out fossil fuels within a matter of decades, without the wholehearted support of the United States, Russia, China and India seems far-fetched, to put it mildly.

Fossil Fuels Are Our Main Source Of Energy

Fossil fuels are the planet’s main sources of energy, and their contribution to the industrial progress of the world is immeasurable. So many of the materials, chemicals and manufacturing processes used in the building, semiconductor, food, medical, transportation and communication industries, depend upon electricity made from fossil fuels like coal and natural gas, while the worldwide development of car travel has been entirely due to a plentiful supply of petrol and diesel. At the same time, fossil fuel-powered domestic heating and air-conditioning systems have made a huge contribution to our quality of life at home. In fact, without fossil fuels, we might still be huddled around wood fires for warmth and in bed by sunset.

Where Do Fossil Fuels Come From?

Fossil fuels are typically (though not always) found in seams or accumulations deep underground, where they have lain for up to 650 million years 2 So, what are fossil fuels made of and how were they formed?

Experts in molecular paleontology believe that coal originated in huge primeval swamps and wetlands, where collapsed – but only partly decayed – trees, ferns and other plants formed concentrated layers of organic material known as peat. In contrast, petroleum (aka crude oil) started out as organic matter in the sediments of coastal marine basins and inland seas. The sources of this material are believed to be the remains of plankton, as well as plant debris swept away by river water.

As both types of organic material sank deeper into the earth, more and more sediment accumulated above them, subjecting them to intense heat and crushing pressure. Over millions of years this caused a number of physical changes that squeezed out all the oxygen. As the plant and animal matter continued to decompose (in the absence of oxygen) at the hands of microbial organisms like bacteria and fungi, it turned into a mixture consisting mostly of hydrocarbons (in the case of petroleum and gas) or mostly carbon (in the case of coal). 3

Who First Coined The Term ‘Fossil Fuel?’
The idea that coal, petroleum and natural gas originated in the fossilized remains of vegetation and plankton after being subjected to heat and pressure deep underground over millions of years, was first written about by the German professor Andreas Libavius (1550-1616) in his textbook “Alchemia” in 1597.

When Were Fossil Fuels First Used For Industrial Purposes?

Their history really starts with the Industrial Revolution. This revolution – which began in Britain during the late 18th century before spreading to Europe, North America, and Japan during the 19th century – created a huge demand for coal to provide power for (a) steam engines and other machines, (b) factories and industrial processes, and (c) steamships. It was the need to maintain coal bunkers around the world to supply passenger and merchant ships that started coal mining around the globe. (Coal was cheaper and much more efficient than wood burning, which up until 1850 remained the main energy source in America.)

In 1700, annual production of coal in Britain was 2.6 million tons. By 1795, this figure had risen to 10 million tons. 4 In 1800, British coal production accounted for 90 percent of the world output. 5 By 1850, production was 62.5 million tons per year.

Thereafter, industrialists on both sides of the Atlantic began to rely exclusively on coal to provide the energy for factories and homes. Manufacturing corporations in Europe and the United States began supplying the world with steel, machine tools and other industrial materials.

From the early 20th century it was the turn of oil. The runaway success of the internal combustion engine, allied to new methods of mass production, created an instant demand for petroleum wherever cars were driven. Ever since then, oil and its derivatives have been (literally) the driving force behind the transportation, aviation and shipping industries. Later, from the late 1940s, the demand for natural gas – the third most common fossil fuel – started to skyrocket following the development of new welding techniques, as well as advances in pipe rolling and metallurgy. This led to a huge increase in the number of possible uses for gas, notably home heating. 6

How Are Fossil Fuels Used?

Fossil fuels are burned to produce energy, including electrical energy. In power plants, for example, it works something like this.

Step 1: Coal (or less often oil) is burned to produce heat.
Step 2: This heat is then used to boil water and create steam. The steam is put under high pressure and then used to turn the blades of a turbine.
Step 3: The spinning turbine causes a coil of wire to interact with a circular arrangement of magnets, located inside a generator.
Step 4: This results in the generation of electricity. This electrical energy is then transmitted across the country via high-voltage transmission lines.
Step 5: At an electrical substation the voltage is lowered before being transmitted on smaller power lines to homes and business.

What’s The Problem With Fossil Fuels?

The secret of fossil fuels is that they contain large amounts of stored energy in the form of hydrocarbon. When hydrocarbons are burned in the presence of oxygen, they release carbon dioxide (CO2) into the atmosphere. Roughly 38 GtCO2e (gigatons, or billion tonnes of CO2) of carbon dioxide is emitted into the atmosphere by fossil fuels every year. 7

Unfortunately, carbon dioxide is a greenhouse gas – meaning, it adds to the “greenhouse effect” by trapping heat rising from the Earth’s surface and radiating it back down to the planet. This man-made greenhouse effect is the No 1. cause of global warming which is causing huge damage to the Planet. And it all stems from the combustion of carbon-rich fossil fuels. Our biggest challenge, therefore, is to reduce our greenhouse gas emissions by switching from high-carbon coal, petroleum and natural gas to low-carbon or no-carbon renewables – a process known as decarbonization.

Another problem with fossil fuels is air pollution. Coal is a major contributor to urban smog (especially the sulfurous variety) and to regional toxic hazes such as the strange Asian Brown Cloud that blankets large parts of India during the winter months. See also: Health Effects of Air Pollution.

50 Climate Change FAQs
50 Global Warming FAQs

Tar Sands Mining at the Syncrude Mildred Lake facility in Alberta, one of the largest fossil fuel sites.
As well as producing CO2 emissions, mining can scar the landscape. Pictured: part of the Syncrude Mildred Lake Tar Sands mining facility in Alberta, Canada. Most of the mine is to the left; in the distance is the huge tailings pond, held in by what is recognized as the largest dam in the world. The yellow matter is stockpiled sulfur. Picture: Public Domain

Replacing Fossil Fuels with Renewables

At the Paris Climate Agreement (2015), an international treaty within the United Nations Framework Convention on Climate Change (UNFCCC), signatories agreed to commit to a progressive reduction in all greenhouse gases (GHGs), especially CO2. In their Special Report on Global Warming of 1.5°C, the Intergovernmental Panel on Climate Change (IPCC) warned that, in order to reduce the worst effects of global warming, man-made CO2 emissions would need to fall by 45 percent by 2030, reaching “net-zero” by 2050. 8

This means replacing fossil fuels as rapidly as possible with cleaner, renewable forms of energy.

There are five major types of renewable energy: solar power, offshore and onshore wind power, organic biomass, underground geothermal energy and hydropower (hydroelectricity).

Next generation renewables include marine energies like wave power and tidal power, both of which are still in development. Nuclear energy is much more controversial. See: Is Nuclear Energy a Replacement for Fossil fuels?

The latest word on renewable power is nuclear fusion, a futuristic quest for limitless amounts of low carbon energy.

How Soon Do We Need To Replace Fossil Fuels With Renewable Energy?

As soon as possible. In their Special Report on Global Warming of 1.5°C, the IPCC stated: First, that by 2050, half to two-thirds of all global energy needs should be met by renewable energy. Second, no more than 10 percent of electricity should be generated by fossil fuels. Thirdly, all fossil fuel usage after 2050 should be neutralized via carbon capture and storage technologies. 8

Fossil Fuel Emissions Gap: Graph
The fossil fuel production gap shows the difference between national production plans and low-carbon pathways (1.5°C and 2°C), as expressed in fossil fuel carbon dioxide (CO2) emissions. It widens between 2015 and 2040. Source: The Production Gap: 2019 Report. UNEP

How Difficult Is It To Replace Fossil Fuels With Renewable Energy?

Very difficult. Here’s why.

  • We use an awful lot of coal, oil and natural gas in our factories, power plants, cars and homes.
  • Overall demand for energy is increasing. Demand for fossil fuels is also up.
  • Due to the rise in population, demand for energy may outstrip the supply capacity of renewables.
  • Renewable energy is less reliable than coal, petroleum or gas.
  • Coal-fired power plants (with a working life of 40-50 years) are still being built.

Global Consumption Of Fossil Fuels

In view of the attention given to climate change over the past decade and the pessimistic global temperature projections for 2100, one would expect to see a noticeable reduction in the use of fossil fuels. But the facts tell a different story. 9

As the following charts show, in 2000, coal, oil and natural gas accounted for 86 percent of the world’s primary energy consumption. In 2019, they accounted for 84.2 percent.

Global Energy Sources (2000)

Primary Energy by Fuel Type 2000
Source: International Energy Agency

Global Energy Sources (2019)

Primary Energy by Fuel Type 2020
Source: BP Statistical Review of World Energy 2020

Global Electricity Generation

Renewables do better in electricity generation. Roughly 26 percent of electrical power comes from renewable sources.

Global Electricity Energy Sources

Global Energy Demand Is Increasing

Global energy consumption has been increasing an average of 2 percent a year. 2019 proved an exception, rising only 1.3 percent, the trend however is still upwards.

China was the biggest individual driver of primary energy growth in 2019 accounting for more than 75 percent of net global growth.

Growth was driven by renewables and natural gas which together contributed three quarters of the increase.

Oil continues to hold the largest share of the energy mix (33%). Coal is the second largest fuel but lost share in 2019 (now 27%), its lowest level since 2003. The share of both natural gas and renewables rose to record highs of 24.2% and 5.0% respectively. Renewables has now overtaken nuclear which makes up only 4.3% of the energy mix. The share of hydroelectricity has been stable at around 6% for several years.

Demand For Fossil Fuels Remains High

There is no sign of a significant decline in demand or production of any fossil fuel. Demand for natural gas is likely to remain strong, with oil not far behind. In Asia, coal will also be strong, though demand in Europe and the United States will decline. Although the trend in respect of renewables is positive, especially in electricity generation, it’s woefully short of what’s needed. Too many governments are unwilling to impose hard choices on their populations and businesses.

Coal Usage

Over the next 5 years demand for coal is set to be stable, with reductions in U.S. and European consumption offset by growth in India and other Asian countries. Demand in China, the main consumer of coal, may decline slightly. Coal’s share of the energy market will decline from 27 to 24 percent, due mainly to the growth of renewable sources and natural gas.

Over the last few years, greater Asian take-up of coal has resulted in the emergence of two worlds: one using more coal, the other using less. This has retarded any major agreement on the phase-out of coal and associated emission reductions. It has also caused an increase in outdoor air pollution across the Indian sub-continent, Bangladesh and Pakistan. Fossil fuel pollution typically contains a high level of microscopic black carbon particles, known as particulates or particulate matter, that are capable of penetrating into the deepest part of the lungs.

In addition, the continuing use of solid fuels (like wood and coal) on indoor open fires for cooking and heating, throughout the developing world, has led to persistently high levels of household air pollution in Africa and Asia.

Theoretically, the technology of carbon capture and storage (CCS) offers the basis of policy consensus between these two worlds. But although there have been advances in this area, global progress in deploying CCUS remains hopelessly off-track compared to what is needed to save the planet. 10

Oil Consumption

World oil production declined slightly from 98.3 million barrels per day to 95.2 Mb/d in 2019. Though as a region the Middle East still produces the largest share of oil worldwide, the United States currently produces more oil than any other country, followed by Saudi Arabia and Russia.

World demand of petrol/diesel oil increased driven mainly by China and India. Demand for petrochemicals (including ethane and naphtha) was also up strongly, boosted by the growth of the shale oil fracking industry. Petrochemicals from oil and natural gas are becoming widespread in the manufacture of many products such as food preservatives, personal care items, furnishings, fertilisers, paints and lubricants for automotive and industrial purposes.

GOOD NEWS: As battery technology improves, the switch from internal combustion vehicles (ICVs) to electric vehicles (EVs), should lead to a huge drop in demand for petroleum.

A pressing issue in the global marine oil market concerns compliance with new rules about marine fuel, introduced by the International Maritime Organisation (IMO). The new regulations are likely to trigger a major move away from high sulphur fuel oil towards marine gasoil or a very low sulphur fuel, although the total demand for oil products should be largely unaffected. 11

Natural Gas Consumption

Global consumption of natural gas has grown at an average of 6.3 percent per year, since 1990. Growth has been even higher in China, averaging 13.1 percent per year over the past 20 years. In 2019, after nine years of continuous year-on-year growth, worldwide consumption increased a further 2.6 percent. China posted the second largest demand growth (+8.6 percent), accounting for 24 percent of the global increase. Consumption grew in the EU (+3.1 percent ) and the United States (+3.1 percent). 10

CO2 Emissions And Concentrations Are Up

In 2019, CO2 emissions from energy use grew by 0.5 percent, less than half the 10-year average growth of 1.1 percent. And significantly down on the unusually strong increase in 2018 (+2.1 percent). 12

The sharp increase in carbon emissions in 2018 was driven in part by extreme weather effects. In particular, an increase in the number of unusually cold and hot days boosting the demand for energy.

According to Spencer Dale, group chief economist at B.P., a 2 percent rise in emissions is roughly the same as “increasing the number of passenger cars on the planet by a third.”

The hope was, that 2019 would bring more ‘normal’ weather and emissions would start to decline. Although the number of extreme weather events did decline, carbon emissions still rose, albeit at a slower pace.

In 2019, concentrations of carbon dioxide (CO2) in the troposphere reached record levels in May, peaking at 414.7 parts per million. For more on this topic, please see our article: What is the Emissions Gap?

Unfortunately, carbon dioxide is not the only greenhouse gas associated with fossil fuels. Methane – which over 20 years traps 84 times more heat than carbon dioxide – is also emitted from coal mines and natural gas infrastructure. See also: Why Are Methane Levels Rising?

Fossil fuel combustion also emits a considerable number of pollutants. Coal, for example, is an active contributor to the man-made sulfur cycle through its emissions of sulfur dioxide. This is the prime cause of acid rain.

Fracking facility in North Dakota. Hydraulic fracturing maximizes fossil fuel output in the oil & gas industry.
Hydraulic fracturing (fracking) in the Williston Basin North Dakota. While the fracking debate in the past decade has focused on how fracking chemicals and methane can contaminate drinking water, scientists say that air pollution is an often overlooked, but is an equally serious problem. Image: Joshua Doubek. CC-SA-3.0

Rise In Population May Outstrip Supply Of Renewable Energy

A 45 percent increase in population by 2100, will lead to an increase in energy demand of at least 80 percent. In addition, as developing nations gain in prosperity, their current population will naturally consume more energy. Demand for food will also skyrocket, placing strains on the environment as well as the power supply. Studies forecast a 50 percent increase in food demand by 2050. 13

Given that renewables supplied a mere 11 percent of global energy in 2018, one might wonder how they are going to raise this figure to 50-66 percent by 2100, let alone supply the energy needs of an extra 3.5 billion people.

Furthermore, according to the IPCC, all fossil fuel emissions after 2050 must be neutralized by carbon capture and storage. For a technology that has yet to prove itself, this expectation seems incredibly optimistic.

Renewable Energy Is Less Reliable Than Coal, Oil Or Gas

Renewable energy comes from entirely natural processes, so it shares some of the latter’s weaknesses. Wind turbines and solar panels require large tracts of land or space to collect energy, as the energy is spread across the environment. What’s more, if the wind subsides or if clouds obscure the sun, energy production declines, perhaps just as a company needs it most. Because of this, renewable energies like solar or wind power must be capable of being stored, in order to contain the energy between production and consumption.

As a general rule, the criteria for power sources feeding into a national electrical grid are low price, availability and reliability. Over the years a variety of power sources have been used. Coal has became the most popular base load supply source, and this is standard throughout much of the world. Nuclear power is also used, notably in France. In the United States, the growing popularity of natural gas will likely replace coal as the base. But as yet, there is no country where the majority of power feeding into a national electrical grid is supplied by wind, solar, geothermal or biofuels, since each of these renewables fails at least one of the criteria of low price, availability and reliability.

Even so, it’s worth emphasizing that long-term use of fossil fuels is incompatible with a hospitable planet. Meaning, if we fail to switch the vast bulk of our energy consumption to cleaner, sustainable energy, then there is absolutely no doubt that Planet Earth and its wonderful natural biodiversity will deteriorate beyond our wildest nightmare. For a better vision, see: What are the Benefits of Renewable Energy?

Coal-Fired Power Plants Are Still Being Built

As stated above, the popularity of coal in Asia has led to the emergence of two worlds: one using more coal, the other using less. Power stations with a working life of 40-50 years are still being planned and built by China and India.

China, who remains dependent on coal for 72 percent of its electricity, is building new coal-fired power plants for its domestic market, but in addition is also building or planning more than 300 coal plants overseas. 14 15

India is also heavily dependent on coal, although its future relationship seems unclear. 16 17 18

Fossil Fuel Politics

For countries whose prosperity is based on the extraction and sale of fossil fuels – Saudi Arabia, Kuwait, Iran, Iraq, UAE, Venezuela (oil), Indonesia, South Africa, Poland (coal), Qatar (gas) – the climate crisis is a threat of major proportions. Politically it is going to be unthinkable for them to renounce fossil fuels without major support from outside.

For more about the politics of global warming, see: UN Climate Talks & Timeline.

The impact of decarbonization on world markets is another imponderable. There are roughly 1,500 oil and gas firms listed on stock exchanges around the world, collectively worth a massive $4.65 trillion. What will happen to global prosperity as the assets of these corporations are written down to a fraction of their previous worth?

These issues do not carry the same existential threat as global warming, but many people will see them as representing a far more immediate danger. 19

These concerns fuel the climate change denial machine that promotes the false notion that there is genuine scientific doubt about the existence of global warming. But see: What’s the Root Cause of Climate Change?


  1. For more about fossil fuels, see for example: NRDC “The Dirty Facts[]
  2. Tectonic setting of the world’s giant oil and gas fields.” Paul Mann, Lisa Gahagan, and Mark B. Gordon, in Giant Oil and Gas Fields of the Decade, 1990–1999, Tulsa, Oklahoma: American Association of Petroleum Geologists, p. 50. []
  3. Introduction to fossil fuels. See: (A) Introduction to Coal. (B) Introduction to Natural Gas. (C) Introduction to Oil. []
  4. A. L. Morton, A People’s History of England (1938) page 284. []
  5. Eric Hobsbawm, Industry and Empire (1968) Weidenfeld and Nicholson. Page 63. []
  6. History of Natural Gas” 2013. []
  7. Emissions Gap Report 2020. UNEP. []
  8. IPCC Special Report on Global Warming of 1.5°C: Summary for policymakers [][]
  9. Persistent fossil fuel growth threatens the Paris Agreement and planetary health.” R B Jackson, P Friedlingstein, R M Andrew, J G Canadell, C Le Quere, G P Peters. Environmental Research Letters, Volume 14, Number 12. 4 December 2019. []
  10. Global Energy Statistical Yearbook 2020 [][]
  11. Global Energy Statistical Yearbook (2019) []
  12. BP Energy Year in Review, 2020 []
  13. How to Sustainably Feed 10 Billion People by 2050.” Janet Ranganathan, Richard Waite, Tim Searchinger, Craig Hanson. World Resources Institute. December 5, 2018. ) []
  14. “Why Is China Placing A Global Bet on Coal?” Steve Inskeep, Ashley Westerman. NPR. April 29, 2019. []
  15. “Out of Step. China is driving the continued growth of the global coal fleet.” (PDF) Christine Shearer, Aiqun Yu, Ted Nace. Global Energy Monitor. November 2019. []
  16. “India expects coal-fired power capacity to grow 22% in 3 years.” Reuters. 31 July 2019. []
  17. “This year, India’s power plants may consume less coal for the first time in a decade.” Kuwar Singh. Quartz India. November 6, 2019. []
  18. “Coal is king in India and will likely remain so.” Samantha Gross. Brookings. Planet Policy. March 8, 2019. []
  19. U.S. Public Views on Climate and Energy. Pew Research. November 2019.  []
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