Fossil fuel

A fossil fuel is a material that contains carbon and can burn. It forms naturally in the Earth's crust from the buried remains of ancient organisms (animals, plants or microplanktons). This happens within geological formations. Fuels such as coal, oil (petroleum) and natural gas can be dug or pumped out and burned. People use them for cooking, heating and lighting. They also power heat engines that move vehicles, and they run steam turbine generators that make electricity. Some fossil fuels are refined into products like kerosene, gasoline and diesel. Others are turned into petrochemicals, such as plastics, aromatics and synthetic resins.

Fossil fuels begin when dead organisms are buried and broken down without oxygen, a process called anaerobic decomposition. Turning these materials into fuels rich in carbon usually takes millions of years. Because they take so long to form, fossil fuels are considered non-renewable resources.

In 2023, fossil fuels provided 77% of the energy consumption in the world and over 60% of its electricity. Burning them causes serious harm to the environment. In 2022, over 70% of the greenhouse gas emissions caused by people came from carbon dioxide (CO₂) released when fossil fuels were burned. Natural carbon cycle processes, mostly the ocean absorbing carbon, can remove only a small part of this. Losing plants through deforestation, land degradation and desertification makes the problem worse. As a result, many billions of tonnes of CO₂ are added to the air each year. Methane leaks are also significant, but burning fossil fuels is the main source of the gases that cause global warming and ocean acidification. Most air pollution deaths are also caused by fossil fuel particulates and harmful gases. It is estimated that this costs over 3% of the global gross domestic product, and that a fossil fuel phase-out would save millions of lives each year.

Many people now recognize the climate crisis, pollution and other harms caused by fossil fuels. This has led to a widespread policy transition and an activist movement that want to stop using them and switch to renewable and sustainable energy. The fossil-fuel industry is deeply connected to the global economy and is heavily subsidized, so this change is expected to have large economic effects. Many people argue that the change must be a just transition, with policies that help with the burdens it places on society from the stranded assets of the fossil fuel industry. International agreements also aim to help this change worldwide. These include the United Nations' sustainable development goals for affordable and clean energy and climate action, and the Paris Climate Agreement. In 2021, the International Energy Agency concluded that no new fossil fuel extraction projects should be opened if the world wants to avoid the worst effects of climate change and meet its goals for climate change mitigation.

For other uses of the words "oil and gas", see Oil and gas (disambiguation).

Origin

The idea that fossil fuels formed from the fossilized remains of dead plants, through heat and pressure in Earth's crust over millions of years, was first introduced by Andreas Libavius "in his 1597 Alchemia [Alchymia]" and later by Mikhail Lomonosov "as early as 1757 and certainly by 1763". The first recorded use of the term "fossil fuel" was in the work of the German chemist Caspar Neumann, in English translation in 1759. The Oxford English Dictionary notes that the word "fossil" in "fossil fuel" meant "[o]btained by digging; found buried in the earth," a meaning dating to at least 1652. Later, the English word "fossil" came to refer mainly to long-dead organisms in the early 1700s.

Tiny sea organisms, phytoplankton and zooplankton, died and settled in large amounts under anoxic conditions millions of years ago. They began forming petroleum and natural gas through anaerobic decomposition. Over geological time, this organic matter, mixed with mud, was buried under more heavy layers of sediment. The high temperature and pressure slowly changed it. It first chemically alter into a waxy material called kerogen, which is found in oil shales, and then, with more heat, into liquid and gas hydrocarbons in a process called catagenesis. Plants on land tend to form coal and methane, and many coal fields date to the Carboniferous period. Land plants also form type III kerogen, a source of natural gas. Fossil fuels are called non-renewable resources because they take millions of years to form, and known supplies are being used up much faster than new ones are made.

Importance

See also: Fossil fuel power station

Fossil fuels have been important to people because they can be burned easily in the open air to make heat. People used peat as a home fuel long before recorded history. Coal was burned in some early furnaces for smelting metal ore. Semi-solid hydrocarbons from oil seeps were also burned in ancient times, but they were mostly used for waterproofing and embalming. Commercial production of petroleum began in the 19th century. Natural gas was once flared-off as an unneeded byproduct of petroleum production, but it is now considered a very valuable resource. Natural gas deposits are also the main source of helium. From the early 2000s, heavy crude oil and oil sands, where bitumen is mixed with sand and clay, became more important fossil fuel sources. Oil shale and similar sedimentary rocks contain kerogen, which yields synthetic crude oil when heated (pyrolyzed). In the 2010s and 2020s, there was disinvestment from these resources because of their high carbon cost compared with easier-to-process reserves.

Before the latter half of the 18th century, windmills and watermills provided energy for work such as milling flour, sawing wood or pumping water, and burning wood or peat provided home heat. The wide use of coal, and later petroleum, in steam engines enabled the Industrial Revolution. At the same time, gas lights using natural gas or coal gas came into wide use. The invention of the internal combustion engine and its use in automobiles and trucks greatly increased the demand for gasoline and diesel oil, both made from fossil fuels. Railways and aircraft also require fossil fuels. Fossil fuels are also used for generating electricity and as feedstock for the petrochemical industry. Tar, a leftover of petroleum extraction, is used in the construction of roads. Fossil fuels also powered the Green Revolution, through fertilizers made from natural gas, pesticides made from oil, and hydrocarbon-fueled irrigation. Synthetic nitrogen fertilizer has greatly supported population growth, and it is estimated that almost half of the Earth's population are currently fed as a result.

Environmental effects

Main articles: Effects of climate change and Health and environmental impact of the coal industry

See also: Extinction risk from climate change

Burning fossil fuels causes harmful externalities, which are effects that reach beyond the people using the fuel. All fossil fuels release CO₂ when they burn, which speeds up climate change. Burning coal, and to a lesser extent oil and its products, adds atmospheric particulate matter, smog and acid rain to the air. In 2018, air pollution from fossil fuels has been estimated to cost US$2.9 trillion, or 3.3% of the global gross domestic product (GDP).

Climate change is mostly driven by greenhouse gases like CO₂, and burning fossil fuels is the main source of them. In most parts of the world, climate change is negatively impacting ecosystems. It helps cause species to die out and makes it harder to grow food, which adds to world hunger. Continued warming will bring more effects on nature and people, and the World Health Organization has said it is the greatest threat to human health in the 21st century. Burning fossil fuels also creates sulfuric and nitric acids, which fall as acid rain and harm nature and buildings. Statues made of marble and limestone are especially at risk, because the acids dissolve calcium carbonate. Fossil fuels also contain radioactive materials, mainly uranium and thorium, which are released into the air. In 2000, about 12,000 tonnes of thorium and 5,000 tonnes of uranium were released worldwide from burning coal, and in 1982 US coal burning was estimated to release 155 times as much radioactivity as the Three Mile Island accident. Burning coal also makes large amounts of bottom ash and fly ash, which are used in many ways (see Fly ash reuse). Coal mining methods such as mountaintop removal and strip mining harm the environment, offshore oil drilling threatens sea life, fugitive gas emissions can release methane, and Oil refineries cause air and water pollution. To counter these harms, people have moved toward renewable energy, and Environmental regulation limits pollution, such as rules against releasing fly ash into the air. In December 2020, the United Nations reported that some governments were "doubling down" on fossil fuels, sometimes sending over 50% of their COVID-19 recovery stimulus money to fossil fuel production. UN secretary general António Guterres said humanity is waging war on nature and that nature is fighting back with growing force, but he also said there was cause for hope as the US planned to join China and the EU in aiming for net zero emissions by 2050.

Inflation effects

Fossilflation is a term that describes how fossil fuels affect inflation, which is when prices rise over time. According to Vox in August 2022, "Economists have pointed to energy prices as the main reason for high inflation," and "energy prices indirectly affect virtually every part of the economy." Higher fossil fuel prices raise costs in transportation, food, and shipping. Mark Zandi of Moody's says that fossil fuel prices have driven every big episode of inflation since WWII. The economic impact of the Russian Invasion of Ukraine in 2022 was a major recent example. Some economists, including Isabel Schnabel, believe that depending on fossil fuels is the main cause of the 2021–2022 inflation spike.

Some people look for ways to fight fossilflation. Gernot Wagner argues that commodities are poor energy sources because their prices are volatile and swing up and down, unlike technologies such as renewable energy. He also says that technologies improve and become cheaper over time. After the COVID-19 pandemic, some argued that a base effect may have made inflation seem worse, since prices were lower than normal at the start of the pandemic and then rose above average. The Inflation Reduction Act is not expected to bring much relief in the short term, but it aims to make the United States less dependent on fossil fuels. Moody's estimates that by 2030, the law could cut the typical American household's energy spending by more than $300 each year, in 2022 dollars.

Illness and deaths

Pollution from fossil fuels harms people's health. Particulates and other air pollution from burning fossil fuels can cause illness and death when people breathe them in. These effects include early death, sudden breathing illnesses, worse asthma, long-lasting bronchitis and weaker lungs. People who are poor, undernourished, very young or very old, or who already have breathing or other health problems, are more at risk. Air pollution from fossil fuels has been estimated to cause over 8 million deaths in 2018, nearly 1 in 5 deaths worldwide, and 10.2 million deaths in 2019. In 2023, there were 5.13 million extra deaths from outdoor air pollution linked to fossil fuel use.

Every energy source has some harmful effects, but fossil fuels cause the most greenhouse gas emissions and are the most dangerous for human health. Modern renewable energy sources appear to be safer and cleaner. The death rates from accidents and air pollution in the EU per terawatt-hour (TWh) are shown below.

As the data shows, coal, oil, natural gas and biomass cause higher death rates and more greenhouse gas emissions than hydropower, nuclear energy, wind and solar power. Scientists propose that 1.8 million lives have been saved by replacing fossil fuel sources with nuclear power.

Phase-out

Industrial sector

Main articles: Coal industry and Petroleum industry

In 2019, Saudi Aramco was listed on the stock market. On its second day of trading, it reached a value of US$2 trillion. It was the world's largest initial public offering.

Subsidies

Lobbying activities