
A fossil fuel is a
fuel formed by
natural processes, such as
anaerobic decomposition of buried dead
organisms, containing
organic molecules originating in ancient
photosynthesis that release energy in
combustion.
[Schmidt-Rohr, K. (2015). "Why Combustions Are Always Exothermic, Yielding About 418 kJ per Mole of O2", ''J. Chem. Educ.'' 92: 2094-2099. http://dx.doi.org/10.1021/acs.jchemed.5b00333]
Such organisms and their resulting fossil fuels typically have an age of millions of years, and sometimes more than 650 million years.
Fossil fuels contain high percentages of
carbon and include
petroleum,
coal, and
natural gas. Commonly used derivatives of fossil fuels include
kerosene and
propane.
Fossil fuels range from
volatile materials with low
carbon-to-
hydrogen ratios (like
methane), to liquids (like petroleum), to nonvolatile materials composed of almost pure carbon, like
anthracite coal.
Methane can be found in
hydrocarbon fields alone, associated with
oil, or in the form of
methane clathrates.
As of 2018, the world's main
primary energy sources consisted of petroleum (34%), coal (27%), and natural gas (24%), amounting to an 85% share for fossil fuels in
primary energy consumption in the world.
Non-fossil sources included
nuclear (4.4%),
hydroelectric (6.8%), and other
renewables (4.0%, including
geothermal,
solar,
tidal,
wind,
wood, and
waste).
The share of renewables (including traditional biomass) in the world's total final energy consumption was 18% in 2018. Compared with 2017, world energy-consumption grew at a rate of 2.9%, almost double its 10-year average of 1.5% per year, and the fastest since 2010.
Although fossil fuels are continually formed by natural processes, they are generally classified as
non-renewable resources because they take millions of years to form and known viable reserves are being depleted much faster than new ones are generated.
Most
air pollution deaths are due to fossil fuel combustion products, it is estimated to cost over 3% of global GDP,
and
fossil fuel phase-out would save 3.6 million lives each year.
The use of fossil fuels raises serious
environmental concerns.
The burning of fossil fuels produces around 35 billion
tonnes (35
gigatonnes) of
carbon dioxide (CO
2) per year.
Natural processes can only absorb a small part of that amount, so there is a net increase of many billion tonnes of atmospheric carbon dioxide per year.
CO
2 is a
greenhouse gas that increases
radiative forcing and contributes to
global warming and
ocean acidification.
A global movement towards the generation of low-carbon
renewable energy is underway to help reduce global
greenhouse gas emissions. But in 2019 fossil fuels were subsidized $320 billion.
Origin

The theory that fossil fuels formed from the
fossilized remains of dead plants by exposure to heat and pressure in the
Earth's crust over millions of years was first introduced by
Andreas Libavius "in his 1597 Alchemia
lchymia and later by
Mikhail Lomonosov "as early as 1757 and certainly by 1763". The first use of the term "fossil fuel" occurs in the work of the German chemist
Caspar Neumann, in English translation in 1759.
The ''
Oxford English Dictionary'' notes that in the phrase "fossil fuel" the adjective "fossil" means "
tained by digging; found buried in the earth", which dates to at least 1652, before the English noun "fossil" came to refer primarily to long-dead organisms in the early 18th century.
Aquatic
phytoplankton and
zooplankton that died and sedimented in large quantities under
anoxic conditions millions of years ago began forming petroleum and natural gas as a result of
anaerobic decomposition. Over
geological time this
organic matter, mixed with
mud, became buried under further heavy layers of inorganic sediment. The resulting high
temperature and
pressure caused the organic matter to chemically
alter, first into a waxy material known as
kerogen, which is found in
oil shales, and then with more heat into liquid and gaseous hydrocarbons in a process known as
catagenesis. Despite these heat driven transformations (which increase the energy density compared to typical organic matter by removal of oxygen atoms),
the energy released in combustion is still photosynthetic in origin.
Terrestrial plants, on the other hand, tended to form
coal and methane. Many of the coal fields date to the
Carboniferous period of
Earth's history. Terrestrial plants also form
type III kerogen, a source of
natural gas.
There is a wide range of organic compounds in any given fuel. The specific mixture of hydrocarbons gives a fuel its characteristic properties, such as density, viscosity, boiling point, melting point, etc. Some fuels like natural gas, for instance, contain only very low boiling, gaseous components. Others such as gasoline or diesel contain much higher boiling components.
Importance

Fossil fuels are of great importance because they can be burned (
oxidized to
carbon dioxide and water), producing significant amounts of
energy per unit mass. The use of
coal as a fuel predates recorded history. Coal was used to run furnaces for the
smelting of
metal ore. While semi-solid hydrocarbons from seeps were also burned in ancient times, they were mostly used for waterproofing and
embalming.
Commercial exploitation of
petroleum began in the 19th century, largely to replace oils from animal sources (notably
whale oil) for use in
oil lamps.
Natural gas, once
flared-off as an unneeded byproduct of petroleum production, is now considered a very valuable resource. Natural gas deposits are also the main source of
helium.
Heavy crude oil, which is much more viscous than conventional crude oil, and
oil sands, where
bitumen is found mixed with sand and clay, began to become more important as sources of fossil fuel in the early 2000s.
Oil shale and similar materials are
sedimentary rocks containing
kerogen, a complex mixture of high-molecular weight organic compounds, which yield
synthetic crude oil when heated (
pyrolyzed). With additional processing, they can be employed instead of other established fossil fuels. More recently, there has been
disinvestment from exploitation of such resources due to their high
carbon cost relative to more easily processed reserves.
Prior to the latter half of the 18th century,
windmills and
watermills provided the energy needed for industry such as milling
flour,
sawing wood or pumping water, while burning wood or
peat provided domestic heat. The wide-scale use of fossil fuels, coal at first and petroleum later, in
steam engines enabled the
Industrial Revolution. At the same time,
gas lights using natural gas or
coal gas were coming 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. Other forms of transportation,
railways and
aircraft, also require fossil fuels. The other major use for fossil fuels is in
generating electricity and as
feedstock for the
petrochemical industry.
Tar, a leftover of petroleum extraction, is used in
construction of roads.
Reserves

Levels of primary energy sources are the reserves in the ground. Flows are production of fossil fuels from these reserves. The most important primary energy sources are
carbon-based fossil energy sources.
Environmental effects

The use of fossil fuels was central to the
industrial revolution and over the past few centuries has helped deliver huge improvements to the
standard of living across the planet. Nevertheless, the burning of fossil fuels has a number of negative
externalities - harmful environmental impacts where the effects extend beyond the people using the fuel. The actual effects depend on the fuel in question. All fossil fuels release when they burn, thus accelerating
climate change. Burning coal, and to a lesser extent oil and its derivatives, contribute to
atmospheric particulate matter,
smog and to
acid rain.
thumb|upright=1.35| In 2020, renewables overtook fossil fuels as the European Union's main source of electricity for the first time.
Climate change is largely driven by the release of greenhouse gasses like , with the burning of fossil fuels being the main source of these emissions. While climate change may have positive effects in some parts of the world, in other parts it is already
negatively impacting ecosystems. This includes contributing to the
extinction of species and reducing people's ability to produce food, thus adding to the problem of
hunger. Continued rises in global temperatures will lead to further adverse
effects on both ecosystems and people, with the
World Health Organization having stated climate change is the greatest threat to human health in the 21st century.
Combustion of fossil fuels generates
sulfuric and
nitric acids, which fall to Earth as acid rain, impacting both natural areas and the built environment. Monuments and sculptures made from
marble and
limestone are particularly vulnerable, as the acids dissolve
calcium carbonate.
Fossil fuels also contain radioactive materials, mainly
uranium and
thorium, which are released into the atmosphere. In 2000, about 12,000
tonnes of thorium and 5,000 tonnes of uranium were released worldwide from burning coal. It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as the
Three Mile Island accident.
Burning coal also generates large amounts of
bottom ash and
fly ash. These materials are used in a wide variety of
applications, utilizing, for example, about 40% of the US production.
In addition to effects that result from burning, the harvesting, processing, and distribution of fossil fuels also has environmental effects.
Coal mining methods, particularly
mountaintop removal and
strip mining, have negative environmental impacts, and
offshore oil drilling poses a hazard to aquatic organisms. Fossil fuel wells can contribute to methane release via
fugitive gas emissions.
Oil refineries also have negative environmental impacts, including air and water pollution. Transportation of coal requires the use of 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 as
renewable energy.
Environmental regulation uses a variety of approaches to limit these emissions, for examples rules against releasing waste products like fly ash into the atmosphere. Other efforts include economic incentives, such as increased taxes for fossil fuels, and subsidies for alternative energy technologies like
solar panels.
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 recovery
stimulus funding to fossil fuel production rather than to alternative energy. The UN secretary general
António 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." Guterres also said there is still cause for hope, anticipating
Joe Biden's plan for the US to join other large emitters like China and the E.U. in adopting targets to reach
net zero emissions by 2050.
Illness and deaths
Environmental pollution from fossil fuels impacts humans because
particulates and other
air pollution from fossil fuel combustion 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. Total global air pollution deaths reach 7 million annually.
While all energy sources have inherently adverse effects, the data shows 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 rate from accidents and air pollution in the EU are as follows per terawatt-hour: coal (24.6 deaths), oil (18.4 deaths), natural gas (2.8 deaths), biomass (4.6 deaths), hydropower (0.02 deaths), nuclear energy (0.07 deaths), wind (0.04 deaths), and solar (0.02 deaths). The greenhouse gas emissions from each energy source are as followed measured in tonnes: coal (820 tonnes), oil (720 tonnes), natural gas (490 tonnes), biomass (78-230 tonnes), hydropower (34 tonnes), nuclear energy (3 tonnes), wind (4 tonnes), and solar (5 tonnes). 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.
Phase-out
Industry
In 2014, the global energy industry revenue was about US$8 trillion,
with about 84% fossil fuel, 4% nuclear, and 12% renewable (including hydroelectric).
In 2014, there were 1,469 oil and gas firms listed on stock exchanges around the world, with a combined market capitalization of US$4.65 trillion.
In 2019,
Saudi Aramco was listed and it touched a US$2 trillion valuation on its second day of trading,
after the world's largest initial public offering.
Economic effects
Air pollution from fossil fuels in 2018 has been estimated to cost US$2.9 trillion, or 3.3% of global GDP.
Subsidy
The
International Energy Agency estimated 2019 global government
fossil fuel subsidies to have been $320 billion.
A 2015 report studied 20 fossil fuel companies and found that, while highly profitable, the hidden economic cost to society was also large.
[
] The report spans the period 2008–2012 and notes that: "For all companies and all years, the economic cost to society of their emissions was greater than their after‐tax profit, with the single exception of
ExxonMobil in 2008."
Pure coal companies fare even worse: "the economic cost to society exceeds total revenue in all years, with this cost varying between nearly $2 and nearly $9 per $1 of revenue."
In this case, total revenue includes "employment, taxes, supply purchases, and indirect employment."
Fossil fuel prices generally are below their actual costs, or their "efficient prices," when
economic externalities, such as the costs of air pollution and global climate destruction, are taken into account. Fossil fuels are subsidized in the amount of $4.7 trillion in 2015, which is equivalent to 6.3% of the 2015 global
GDP and are estimated to grow to $5.2 trillion in 2017, which is equivalent to 6.5% of global GDP. The largest five subsidizers in 2015 were the following: China with $1.4 trillion in fossil fuel subsidies, United States with $649 billion, Russia with $551 billion, the European Union with $289 billion, and India with $209 billion. Had there been no subsidies for fossil fuels, global carbon emissions would have been lowered by an estimated 28% in 2015, air-pollution related deaths reduced by 46%, and government revenue increased by $2.8 trillion or 3.8% of GDP.
[International Monetary Fund (IMF), May 2019]
"IMF Working Paper, Global Fossil Fuel Subsidies Remain Large: An Update Based on Country-Level Estimates"
Abstract and p. 24, WP/19/89
See also
*
Abiogenic petroleum origin proposes that petroleum is not a fossil fuel
*
Bioremediation
*
Carbon bubble
*
Environmental impact of the energy industry
*
Externality
*
Fossil Fools Day
*
Fossil Fuel Beta
*
Fossil fuel divestment
*
Fossil fuel drilling
*
Fossil fuel exporters
*
Fossil fuel phase-out
*
Fossil fuels lobby
*
Fugitive gas emissions
*
Hydraulic fracturing
*
Liquefied petroleum gas
*
Low-carbon power
*
Peak coal
*
Peak gas
*
Petroleum industry
*
Phase-out of fossil fuel vehicles
*
Resource decoupling
*
Shale gas
*
Oil shale
Footnotes
Further reading
* Ross Barrett and Daniel Worden (eds.), ''Oil Culture.'' Minneapolis, MN: University of Minnesota Press, 2014.
* Bob Johnson, ''Carbon Nation: Fossil Fuels in the Making of American Culture.'' Lawrence, KS: University Press of Kansas, 2014.
External links
Global Fossil Infrastructure TrackerCentre for Research on Energy and Clean Air
{{DEFAULTSORT:Fossil Fuel