The origin of fossil fuels is theanaerobic decomposition of buried dead organisms. The conversion from these organic materials to high-carbon fossil fuels is typically the result of a geological process of millions of years.[4] Due to the length of time it takes for them to form, fossil fuels are considerednon-renewable resources.
In 2023, 77% of primaryenergy consumption in the world[5] and over 60% of its electricity supply were from fossil fuels.[6] The large-scale burning of fossil fuels causes serious environmental damage. Over 70% of thegreenhouse gas emissions due to human activity in 2022 wascarbon dioxide (CO2) released from burning fossil fuels.[7] Naturalcarbon cycle processes on Earth, mostly absorption by the ocean, can remove only a small part of this, and terrestrial vegetation loss due todeforestation,land degradation anddesertification further compounds this deficiency. Therefore, there is a net increase of many billion tonnes of atmospheric CO2 per year.[8] Althoughmethane leaks are significant,[9]: 52 the burning of fossil fuels is the main source of greenhouse gas emissions causingglobal warming andocean acidification. Additionally, most air pollution deaths are due to fossil fuelparticulates and noxious gases, and it is estimated that this costs over 3% of the globalgross domestic product[10] and thatfossil fuel phase-out will save millions of lives each year.[11][12]
Sinceoil fields are located only at certain places on Earth,[20] only some countries are oil-independent; the other countries depend on the oil-production capacities of these countries.
The theory that fossil fuels formed from thefossilized remains of dead plants by exposure to heat and pressure inEarth's crust over millions of years was first introduced byAndreas Libavius "in his 1597 Alchemia [Alchymia]" and later byMikhail Lomonosov "as early as 1757 and certainly by 1763".[21] The first recorded use of the term "fossil fuel" occurs in the work of the German chemistCaspar Neumann, in English translation in 1759.[22] TheOxford English Dictionary notes that, in the phrase "fossil fuel", the adjective "fossil" means "[o]btained by digging; found buried in the earth", which dates to at least 1652,[23] before the English noun "fossil" came to refer primarily to long-dead organisms in the early 18th century.[24]
Aquaticphytoplankton andzooplankton that died and sedimented in large quantities underanoxic conditions millions of years ago began forming petroleum and natural gas as a result ofanaerobic decomposition. Overgeological time thisorganicmatter, mixed with mud, became buried under further heavy layers of inorganic sediment. The resulting high temperature andpressure caused the organic matter to chemicallyalter, first into a waxy material known askerogen, which is found inoil shales, and then with more heat into liquid and gaseous hydrocarbons in a process known ascatagenesis. Despite these heat-driven transformations, the energy released in combustion is still photosynthetic in origin.[25]
Terrestrial plants tend to form coal and methane. Many of the coal fields date to theCarboniferous period of Earth's history. Terrestrial plants also formtype III kerogen, a source of natural gas. Although fossil fuels are continually formed by natural processes, they are classified asnon-renewable resources because they take millions of years to form and known viable reserves are being depleted much faster than new ones are generated.[26][27]
Net income of the global oil and gas industry reached a record US$4 trillion in 2022.[28]After recovering from theCOVID-19 pandemic, energy company profits increased with greater revenues from higher fuel prices resulting from theRussian invasion of Ukraine, falling debt levels,tax write-downs of projects shut down in Russia, and backing off from earlier plans to reducegreenhouse gas emissions.[29] Record profits sparked public calls forwindfall taxes.[29]
Fossil fuels have been important to human development because they can be readily burned in the open atmosphere to produce heat. The use ofpeat as a domestic fuel predates recorded history. Coal was burned in some early furnaces for thesmelting ofmetal ore, while semi-solid hydrocarbons from oil seeps were also burned in ancient times,[30] they were mostly used for waterproofing andembalming.[31]
Commercial exploitation of petroleum began in the 19th century.[32]
Natural gas, onceflared-off as an unneeded byproduct of petroleum production, is now considered a very valuable resource.[33] Natural gas deposits are also the main source ofhelium.
Heavy crude oil, which is much more viscous than conventional crude oil, andoil sands, wherebitumen is found mixed with sand and clay, began to become more important as sources of fossil fuel in the early 2000s.[34] Oil shale and similar materials aresedimentary rocks containingkerogen, a complex mixture of high-molecular weight organic compounds, which yieldsynthetic crude oil when heated (pyrolyzed). With additional processing, they can be employed instead of other established fossil fuels. During the 2010s and 2020s there wasdisinvestment from exploitation of such resources due to their highcarbon cost relative to more easily-processed reserves.[35]
Prior to the latter half of the 18th century,windmills andwatermills provided the energy needed for work such as milling flour,sawing wood or pumping water, while burning wood orpeat provided domestic heat. The wide-scale use of fossil fuels, coal at first and petroleum later, insteam engines enabled theIndustrial Revolution. At the same time,gas lights using natural gas orcoal gas were coming into wide use. The invention of theinternal combustion engine and its use inautomobiles and trucks greatly increased the demand for gasoline anddiesel oil, both made from fossil fuels. Other forms of transportation, railways and aircraft, also require fossil fuels. The other major use for fossil fuels is ingenerating electricity and asfeedstock for thepetrochemical industry.Tar, a leftover of petroleum extraction, is used in theconstruction of roads.
The energy for theGreen Revolution was provided by fossil fuels in the form offertilizers (natural gas),pesticides (oil), andhydrocarbon-fueledirrigation.[36][37] The development of synthetic nitrogen fertilizer has significantly supported globalpopulation growth; it has been estimated that almost half of theEarth's population are currently fed as a result of synthetic nitrogen fertilizer use.[38] According to head of a fertilizers commodity price agency, "50% of the world's food relies on fertilisers."[39]
TheGlobal Carbon Project shows how additions to CO2 since 1880 have been caused by different sources ramping up one after another.
The burning of fossil fuels has a number of negativeexternalities – harmful environmental consequences where the effects extend beyond the people using the fuel. These effects vary between different fuels. All fossil fuels release CO2 when they burn, thus acceleratingclimate change. Burning coal, and to a lesser extent oil and its derivatives, contributes toatmospheric particulate matter, smog andacid rain.[40][41][42]Air pollution from fossil fuels in 2018 has been estimated to cost US$2.9 trillion, or 3.3% of the globalgross domestic product (GDP).[10]
Global surface temperature reconstruction over the last 2000 years using proxy data from tree rings, corals, and ice cores in blue.[43] Directly observational data is in red, with all data showing a 5 year moving average.[44]
Climate change is largely driven by the release of greenhouse gases like CO2, and the burning of fossil fuels is the main source of these emissions. In most parts of the world climate change isnegatively impacting ecosystems.[45] This includes contributing to the extinction of species and reducing people's ability to produce food, thus adding to the problem ofworld hunger. Continued rises in global temperatures will lead to further adverseeffects on both ecosystems and people; theWorld Health Organization has said that climate change is the greatest threat to human health in the 21st century.[46][47]
Combustion of fossil fuels generatessulfuric andnitric acids, which fall to Earth as acid rain, impacting both natural areas and the built environment. Monuments and sculptures made frommarble andlimestone are particularly vulnerable, as the acids dissolvecalcium carbonate.
Fossil fuels also contain radioactive materials, mainlyuranium andthorium, which are released into the atmosphere. In 2000, about 12,000tonnes of thorium and 5,000 tonnes of uranium were released worldwide from burning coal.[48] It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as theThree Mile Island accident.[49]
Burning coal also generates large amounts ofbottom ash andfly ash. These materials are used in a wide variety of applications (seeFly ash reuse), utilizing, for example,[clarification needed] about 40% of the United States production.[50]
In addition to the effects that result from burning, the harvesting, processing, and distribution of fossil fuels also have environmental effects.Coal mining methods, particularlymountaintop removal andstrip mining, have negative environmental impacts, andoffshore oil drilling poses a hazard to aquatic organisms. Fossil fuel wells can contribute to methane release viafugitive gas emissions.Oil refineries also have negative environmental impacts, including air and water pollution. Coal is sometimes transported by diesel-powered locomotives, while crude oil is typically transported by tanker ships, requiring the combustion of additional fossil fuels.
A variety of mitigating efforts have arisen to counter the negative effects of fossil fuels. This includes a movement to use alternative energy sources, such asrenewable energy.Environmental regulation uses a variety of approaches to limit these emissions; for example, rules against releasing waste products like fly ash into the atmosphere.[42]
In December 2020, the United Nations released a report saying that despite the need to reduce greenhouse emissions, various governments are "doubling down" on fossil fuels, in some cases diverting over 50% of their COVID-19 recoverystimulus funding to fossil fuel production rather than to alternative energy. The UN secretary generalAntónio Guterres declared that "Humanity is waging war on nature. This is suicidal. Nature always strikes back – and it is already doing so with growing force and fury." He also claimed there is still cause for hope, anticipating the US plan to join other large emitters like China and the EU in adopting targets to reachnet zero emissions by 2050.[52][53][54]
Inflation effects
Fossilflation is a term that describes the impact of fossil fuels oninflation.[55][56]
According toVox in August 2022, "Economists have pointed to energy prices as the main reason for high inflation", noting that "energy prices indirectly affect virtually every part of the economy".[55] Sectors that raise prices significantly as a result of higher fossil fuel prices include transportation, food, and shipping.[55]
History
Mark Zandi ofMoody's says that fossil fuel prices have driven every big episode of inflation since WWII.[55]
Gernot Wagner argues thatcommodities are undesirable energy sources because they are susceptible tovolatile price swings that technologies like renewable energy are not. He also argues that technologies improve and get relatively cheaper over time.[55][57] Coming out of the COVID-19 pandemic, some argued for the possibility of abase effect phenomenon due to cheaper than normal prices, such as for oil, at the onset of the pandemic, followed by above-average prices which exacerbated the perceived inflation.[58][59]
Inflation Reduction Act
While not expected to provide much short-term relief, theInflation Reduction Act seeks to make the United States less dependent on fossil fuels and their ability to cause inflation in the economy.[55][60][57]Moody's estimates that by 2030, the bill could reduce the typical American household's spending on energy by more than $300 each year, in 2022 dollars.[55]
Illness and deaths
Deaths caused as a result of fossil fuel use (areas of rectangles in chart) greatly exceed those resulting from production ofrenewable energy (rectangles barely visible in chart).[61]
Environmental pollution from fossil fuels impacts humans becauseparticulates and other air pollution from fossil fuel combustion may cause illness and death when inhaled. These health effects include premature death, acute respiratory illness, aggravated asthma, chronic bronchitis and decreased lung function. The poor, undernourished, very young and very old, and people with preexisting respiratory disease and other ill health are more at risk.[62] Global air pollution deaths due to fossil fuels have been estimated at over 8 million people (2018, nearly 1 in 5 deaths worldwide)[63] at 10.2 million (2019),[64] and 5.13 million excess deaths from ambient air pollution from fossil fuel use (2023).[65]
While all energy sources inherently have adverse effects, the data show that fossil fuels cause the highest levels of greenhouse gas emissions and are the most dangerous for human health. In contrast, modern renewable energy sources appear to be safer for human health and cleaner. The death rates from accidents and air pollution in the EU are as follows perterawatt-hour (TWh):
Energy source
Nos. of deaths per TWh
Greenhouse gas emissions (thousand tonnes/TWh)
Coal
24.6
820
Oil
18.4
720
Natural gas
2.8
490
Biomass
4.6
78–230
Hydropower
0.02
34
Nuclear energy
0.07
3
Wind
0.04
4
Solar
0.02
5
[66] As the data shows, coal, oil, natural gas, and biomass cause higher death rates and higher levels of 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.[67]
Phase-out
Investment in clean energy 2015-2025, compared to fossil fuels. As of 2025, investment in clean energy is about twice that for fossil fuels (oil, natural gas and coal).[68]
This article needs to beupdated. The reason given is: Needs to incorporate developments in international law and climate law which now recognise just transition. Please help update this article to reflect recent events or newly available information.(September 2024)
Just transition is a concept that emerged in the 1980s through efforts by U.S.trade unions to protectworkers' rights and livelihoods as economies shift tosustainable production, primarily protecting workers affected by environmental regulations.[73] Since then, it has evolved and gained global recognition, including having a place in theParis Agreement in 2015. A just transition focuses on the connection betweenenergy transition and equitable approaches todecarbonization that support broaderdevelopment goals.[74][75] A growing number of countries are incorporating just transition strategies to achieve ambitious climate goals, with 38% of 170 countries referring to just transition in their short-term climate plans as of 2022.[74]
As of 2021, 1,300 institutions possessing US$14.6 trillion have divested from the fossil fuel industry.[76]
Fossil fuel divestment or fossil fuel divestment and investment in climate solutions is an attempt to reduceclimate change by exerting social, political, and economic pressure for the institutionaldivestment of assets including stocks, bonds, and other financial instruments connected to companies involved in extractingfossil fuels.[77]
Fossil fuel divestment campaigns emerged on college and university campuses in theUnited States in 2011 with students urging their administrations to turnendowment investments in thefossil fuel industry into investments in clean energy and communitiesmost impacted by climate change.[78] In 2012,Unity College inMaine became the first institution of higher learning to divest[79] its endowment from fossil fuels.
By 2015, fossil fuel divestment was reportedly the fastest growingdivestment movement in history.[80] As of July 2023, more than 1593 institutions with assets totalling more than $40.5 trillion in assets worldwide had begun or committed some form of divestment of fossil fuels.[81]
Divesters cite several reasons for their decisions. To some, it is a means of aligning investments with core values; to others, it is a tactic for combatting the fossil fuel industry; to others, it is a way to protect portfolios fromclimate-related financial risk.[82] Financial research suggests that, in the longer term, fossil fuel divestment has positively impacted investors' returns.[83][84]
In 2019,Saudi Aramco was listed and it reached a US$2 trillion valuation on its second day of trading,[85] after the world's largest initial public offering.[86]
Despite theG20 countries having pledged to phase-out inefficient fossil fuel subsidies,[92] as of 2023[update] they continue because of voter demand,[93][94] or forenergy security.[95]
For example, afterclimate change became a public topic, the fossil fuel lobby began a massive public relations campaign to undermine public understanding of climate change and block meaningful policy action. Since then, the fossil fuel industry has actively denied and cast doubt on climate science, confused the public and politicians, and prevented climate and clean energy policies through disinformation, lobbying, and propaganda and continues to do so, for example by falsely claiming there is no climate consensus among scientists.[99]
Lobbies are active in most fossil-fuel intensive economies with democratic governance, with reporting on the lobbies most prominent in Canada, Australia, the United States and Europe; however, the lobbies are present in many parts of the world.Big Oil companies such asExxonMobil,Shell,BP,TotalEnergies,Chevron Corporation, andConocoPhillips are among the largestcorporations associated with the fossil fuels lobby.[100] TheAmerican Petroleum Institute is a powerfulindustry lobbyist for Big Oil with significant influence inWashington, D.C.[101][102][103] In Australia,Australian Energy Producers, formerly known as the Australian Petroleum Production and Exploration Association (APPEA), has significant influence in Canberra and helps to maintain favorable policy settings for Oil and Gas.[104]
^"fossil".Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription orparticipating institution membership required.) – "fossil [...] adj. [...] Obtained by digging; found buried in the earth. Now chiefly of fuels and other materials occurring naturally in underground deposits; esp. in FOSSIL FUEL n."
^"fossil".Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription orparticipating institution membership required.) – "fossil [...] n. [...] Something preserved in the ground, esp. in petrified form in rock, and recognizable as the remains of a living organism of a former geological period, or as preserving an impression or trace of such an organism."
^abWagner, Gernot (23 February 2024)."The Ukraine War Blew Up the World's Energy Economy".heatmap.news. Retrieved18 August 2024.Throughout the most recent U.S. spike in inflation in 2022, the energy category alone was responsible for around half of total inflation. And that's just counting the direct effects. Indirectly, a good portion of the food price increases ever since are also due to higher energy costs. If the farmer pays more to harvest the crop, soon those commodity prices increase as well. Of course, it isn't all fossil fuels...The IRA has not and will not cut inflation overnight. But that fight is indeed a big part of the bill's legacy: Play the long game of tackling all three types of climate-related inflation — fossilflation, climateflation, and greenflation — at their very core, and indeed justify the law's name.
^Ritchie, Hannah; Roser, Max (2021)."What are the safest and cleanest sources of energy?".Our World in Data.Archived from the original on 15 January 2024. Data sources: Markandya & Wilkinson (2007); UNSCEAR (2008; 2018); Sovacool et al. (2016); IPCC AR5 (2014); Pehl et al. (2017); Ember Energy (2021).
^Liodakis, E; Dashdorj, Dugersuren; Mitchell, Gary E. (2011).The nuclear alternative: Energy Production within Ulaanbaatar, Mongolia. AIP Conference Proceedings. Vol. 1342. p. 91.Bibcode:2011AIPC.1342...91L.doi:10.1063/1.3583174.
^Shaye Wolf et al.:Scientists' warning on fossil fuels, in:Oxford Open Climate Change, Volume 5, Issue 1, 2025,doi:10.1093/oxfclm/kgaf011 This article incorporates text available under theCC BY 4.0 license.
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