Petroleum – one of the most versatile fossil fuels – continues to exert a damaging effect on the global climate system and on the air quality of cities around the world. Its widespread use as a transport and heating fuel has liberated millions of people but at a huge cost to our environment.
The introduction of electric vehicles (EVs), powered by electricity from renewable energy, will help to reduce oil-based greenhouse gas emissions but oil companies need to make a much greater effort to decarbonize, if we are to resolve our climate crisis by the end of the century. To understand why fossil fuel companies (and governments) have been so slow to take action on emissions, see: What’s the Root Cause of Climate Change?
What is Petroleum?
Petroleum – the word comes from the Latin “petro” (rock) and “leum” (oil) – is a flammable, liquid fossil fuel which contains primarily hydrocarbon compounds together with small amounts of oxygen, sulfur, and nitrogen compounds. It exists in liquid form in underground pools or reservoirs, typically in tiny spaces within sedimentary rocks.
Conventional oil deposits are usually extracted by drilling deep into the earth or sea bed. Three less conventional deposits include: tar sands, tight oil and oil shale. Tar sands, a mix of sand, clay, water and bitumen, are found nearer the surface in areas such as Canada’s Athabasca oil sands, or Venezuela’s Orinoco Belt. Tar sands oil is either mined on the surface or pumped out in-situ. Tight oil is crude oil which occurs naturally in shale rock, and is extracted using hydraulic fracturing, or “fracking.” Oil shale is a sedimentary rock which contains kerogen (a solid mixture of organic compounds) from which liquid hydrocarbons (shale oil) can be processed. Proven global oil reserves amount to 1.73 trillion barrels.
What’s the difference between oil and petroleum?
Oil – in this case meaning crude oil – is a hydrocarbon fossil fuel that is typically found in the form of liquid deposits, deep underground. When brought to the surface it is usually refined (separated, converted and treated) in order to meet user requirements. Petroleum is a broader category of fossil fuels that includes crude oil as well as all the different petroleum products (such as, aviation fuel, gasoline, heating oil, asphalt) that are made from crude oil in the refinery. That said, the terms oil and petroleum are often used interchangeably.
- What’s The Problem With Petroleum?
- Greenhouse Gas Emissions From The Average Car
- Emissions From Petroleum Production And Distribution
- Petroleum: A Brief History
- Who Are The World’s Largest Petroleum Companies?
- What Are The Main Types Of Oil?
- What Are The Main Uses Of Petroleum?
- What Is Tight Oil?
- What Is Oil Shale?
- What Is Tar Sands Oil?
- How Is Tar Sands Oil Extracted?
- Pollution Caused by Tar Sands Mining Activities
- Greenhouse Gas Emissions from Tar Sands Mining
- Environmental Concerns About Petroleum
- How Much Oil Do We Produce?
- How Much Oil Do We Have Left?
Petroleum is much more versatile than either natural gas or coal. It can be refined or processed into numerous derivatives, such as: gasoline/petrol for vehicles; diesel for engines; kerosene, also known as paraffin, for heating; and liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), also called propane or butane, for cooking and heating. Other more specialized derivatives include aviation fuel and naphtha.
Petroleum refineries in the United States produce about 19 to 20 gallons of motor gasoline and 11 to 12 gallons of ultra-low sulfur distillate fuel oil (most of which is sold as diesel fuel and in several states as heating oil) from one 42-gallon barrel of crude oil.
Petroleum surpassed coal as the world’s foremost fuel in the late-1950s. Today, according to market research by IBISWorld, estimated revenues in 2019 for the oil and gas exploration and production industry (E&P), which includes crude oil and natural gas, amount to $3 trillion in 2019, or roughly 3.4 percent of the global economy, employing some 4,101,097 workers. 1
What’s The Problem With Petroleum?
The problem is climate change, which most experts say will make Planet Earth increasingly inhospitable – perhaps even uninhabitable. This climate crisis has arisen because of excessive man-made emissions of carbon dioxide and other so-called greenhouse gases caused by the burning of fossil fuels like petroleum. These greenhouse gases trap heat in the lower part of the atmosphere, seriously overloading the usually benign “greenhouse effect” in the process. Global temperature projections for 2100, prepared by the Intergovernmental Panel on Climate Change 2 show that if we wish to avoid the worst effects of global warming, we need to reduce our greenhouse gas emissions by 45 percent by 2030, so as to reach net-zero emissions by 2050. This means we need to replace petroleum, as well as coal and natural gas, with emission-free renewable energy as soon as it is practical.
Greenhouse Gas Emissions From The Average Car
Here are the latest emission figures from the U.S. Environmental Protection Agency (EPA). 3
- The average gasoline/petrol-powered car emits about 404 grams of carbon dioxide (CO2) per mile.
- The average diesel car emits about 463 grams of CO2 per mile.
- A gallon of gasoline/petrol emits about 8.87 kilograms of CO2.
- A gallon of diesel emits about 10.18 kilograms of CO2.
- A gallon of biodiesel (diesel with 10% biofuel) emits about 9 kilograms of CO2.
- A typical gasoline/petrol car emits about 4.6 metric tons of carbon dioxide per year. (This assumes a fuel economy of about 22.0 miles per gallon and mileage of about 11,500 miles per year.
- Vehicle exhaust fumes from the combustion of petroleum are a key component, along with ground level ozone and sunlight, of photochemical smog that plagues urban areas around the world.
In addition to carbon dioxide, vehicles also emit methane (CH4) and nitrous oxide (N2O) from the tailpipe/exhaust. While much smaller than CO2 emissions, the impact of CH4 and N2O is important because of their higher heat-trapping qualities (global warming potential).
In addition to greenhouse gas emissions, vehicles also pollute the atmosphere with carbon monoxide and other toxic compounds like formaldehyde and benzene, as well as particulate matter – microscopic partially combusted fragments, also known as aerosols. In total, vehicles produce about 33 percent of all U.S. air pollution. 4
Emissions From Petroleum Production And Distribution
Producing and transporting the fuel used to power our vehicles also generates greenhouse gases. Oil needs to be extracted from the ground, moved to a refinery, refined into gasoline, and then distributed to service stations. Each of these steps produces additional emissions of CO2, CH4 and N2O.
What Emissions Are Produced By Electric Vehicles?
Electric vehicles (EVs) do not produce any toxic tailpipe emissions or pollutants of any kind. And if their batteries are recharged using clean electricity, they produce zero greenhouse gas emissions. However, the manufacture of the car itself does produce emissions.
Petroleum: A Brief History
The earliest known oil wells were drilled in China, using bamboo drill bits, during the 4th century BC. 5 The resulting oil was mainly used as fuel for domestic heating. By the 8th century AD, city streets in Baghdad, Mesopotamia (present day Iraq), were surfaced with tar, made from petroleum. The distillation of petroleum into lamp oil, was widespread within the Islamic kingdom. 6 This knowledge entered Europe during the 11th century via Islamic Spain during the Al-Andalus civilization, reaching Alsace, Switzerland, Romania, Russia and other countries.
Early sources of fuel for lamps included a variety of plant and nut oils, as well as animal fats such as shark liver and seal oil, with whale oil becoming the most desired lighting oil in America by the mid-19th century. 9
The first modern commercial oil well is popularly thought to be Edwin Drake’s 1859 well, located near Titusville, Pennsylvania, USA. 10 Drilled for the Seneca Oil Company, the well’s annual output was around 15 barrels per day. Drake was not searching for motor gasoline – engines were still powered by coal and cars were yet to appear. Instead he was looking for a source of kerosene to be used for lighting.
Around the same time as Drake began drilling, the rising price of whale oil, together with new taxes on alcohol-based alternatives like camphene, gave petroleum-based kerosene – newly invented by Samuel Martin Kier – a key price advantage. As a result, the lighting industry in America moved over completely to petroleum during the 1860s, until Edison began building public electric lighting systems in 1882. 11
The invention of the motor car with its internal combustion engine changed everything, and gave petroleum its unique identity and value. The automobile was invented and perfected in Germany and France during the late 1800s, but it was the American mass-production techniques and assembly line concept, pioneered by the Ford Motor Co, that quickly came to dominate the automotive industry.
The oil and automobile industries boomed together. In 1900 there were about 8,000 registered vehicles; by 1920 there were 23 million. In 1913, America built 485,000 of the world’s 606,124 motor vehicles. By the 1920s, the three biggest car companies were Ford, General Motors and Chrysler. By 1927, 15 million Model T Ford cars had been sold. 12
In the beginning, however, it was by no means clear that gasoline would be used to fuel the automobile. Early car models were powered by steam and electricity (mostly) as well as gasoline. Yet, gasoline turned out to be the most practical fuel because battery-powered engines lacked sufficient range.
Another worry was oil production. Fortunately, the 1901 oil strike at Spindletop, near Beaumont, Texas, launched large-scale oil production and soon made petroleum widely available. 13
With the huge increase in car sales, petroleum production skyrocketed. (Even today, about 90 percent of all automobile fuel needs are met by oil.) In 1859, the U.S. produced 2,000 barrels of oil. By 1906, that number had jumped to 126 million barrels per year. Today, the U.S. produces 11.7 million barrels of crude oil per day, with petroleum making up up 36 percent of total energy consumption. 14
During the 20th century, significant oil finds were made in Persia, Venezuela, Saudi Arabia, Canada and Russia.
In terms of the global oil market, World War I was a pivotal moment. During its lifetime, the world moved imperceptibly from being horse-drawn to being motorized. When Britain entered the war, it possessed about 16,000 motor vehicles. 15 By the end, Britain had 56,000 trucks and 36,000 cars. The introduction of motorized transport led to the development of the tank and the airplane, which revolutionized war as well as the subsequent peace.
Before WWI, oil had been seen purely as a commodity. Afterwards, it was viewed as a vital strategic asset. Hence the rush by European nations like Britain and France to secure their access to oil, notably in Mesopotamia (present-day Iraq), where oil had been found in 1908. The United States however remained the world’s leading oil producer until the 1940s, accounting for roughly 65 percent of global oil production.
Then came the event that changed the political geography of Saudi Arabia and the Middle East, for ever. It happened on March 3, 1938, when an American-owned oil well in Dhahran, Saudi Arabia, drilled into what would become the largest reservoir of crude oil in the world. Prior to the discovery, Saudi Arabia was home to a largely nomadic people, and its economy was reliant upon revenue earned from Muslim pilgrimages to the holy city of Mecca. But the discovery of oil gave it enormous political as well as economic influence. Further major discoveries in Kuwait (1938) and United Arab Emirates (1958) only added to the oil reserves in Iran and Iraq, and gave the Middle East a growing hold on the market.
By the early-1970s, the Middle East was supplying 80 percent of all European oil and 90 percent of Japanese oil. This led to two major “oil shocks”. The first occurred in 1973 following the Yom Kippur War; the second came in 1978-79 after the fall of the Shah of Iran. Fortunately, neither proved to be lasting affairs, although they stimulated the take-up of nuclear energy as an alternative to fossil fuels like oil. Lately, the discovery and development of major deposits of tar sand oil and tight oil, has led to a significant increase in crude oil along with lower price levels.
How many gallons of oil are found in one barrel?
One barrel contains 42-gallons of oil. This typically provides 19.5 gallons of petrol/gasoline and 11.5 gallons of ultra-low sulfur distillate fuel oil, usually marketed as diesel fuel or heating oil. 16
Who Are The World’s Largest Petroleum Companies?
The complex world of international oil trading gave rise to the “Seven Sisters“, a nickname given to the seven transnational oil companies that dominated the global petroleum industry from the mid-1940s to the mid-1970s. They consisted of:
(1) Anglo-Iranian Oil Company (now BP);
(2) Gulf Oil (now Chevron);
(3) Royal Dutch Shell;
(4) Standard Oil Company of California (now Chevron);
(5) Standard Oil Company of New Jersey (Esso, now part of ExxonMobil);
(6) Standard Oil Company of New York (now part of ExxonMobil);
(7) Texaco (now a subsidiary of Chevron).
Prior to the early 1970s, the Seven Sisters controlled around 85 per cent of the world’s petroleum reserves. 17
Today, the largest oil (and gas) companies include: 18
China Petroleum & Chemical Corporation (revenue: $426bn)
Royal Dutch Shell (revenue: $426bn)
Saudi Aramco (revenue: $388bn)
China National Petroleum Corp (revenue: $346bn)
BP Plc (revenue: $298bn)
ExxonMobil (revenue: $290bn)
Total (revenue: $209bn)
Chevron (revenue: $158bn)
Rosneft (revenue: $133bn)
Lukoil (revenue: $115bn)
What Are The Main Types Of Oil?
Crude Oil varies enormously in both density and consistency. It ranges from a very thin, volatile liquid to an extremely thick, semi-solid heavy weight sludge. Its colour varies from a light golden yellow to a dark black. The oil industry classifies crude oil into four main categories based on three things: viscosity, volatility, and toxicity.
Viscosity denotes an oil’s flowability. Higher viscosity oils do not flow as easily and therefore require more energy to pump from the ground. Volatility measures how quickly the oil evaporates. The higher an oil’s volatility the more processes need to be in place during extraction to ensure that the minimum amount of oil is lost. Toxicity refers to an oil’s power to contaminate the environment, during its extraction and refinement.
The four main types of crude oil are:
Very Light Oils
These include: Jet Fuel, Gasoline, Kerosene, Petroleum Spirit, Light Virgin Naphtha, Heavy Virgin Naphtha, Petroleum Ether, Petroleum Spirit, and Petroleum Naphtha. They tend to be very volatile, and can evaporate within a few days which in turn diffuses and reduces their toxicity levels.
These include Grade 1 and Grade 2 Fuel Oils, and Diesel Fuel Oils as well as most Domestic Fuel Oils and Light Crude Marine Gas Oils. They are moderately volatile, less evaporative and moderately toxic.
Most of the crude oil on the market falls into this category. Typically, they have low volatility and a higher viscosity than the light oils. This results in a higher toxicity and therefore a greater environmental impact after spills.
Heavy Fuel Oils
These include the heavy crude oils, Grade 3,4,5 and 6 Fuel Oils, as well as Intermediate and Heavy Marine Fuels. These are the most viscous and least volatile Crude Oils, and the most toxic. They have the potential to cause severe, long term contamination of local water systems, habitats and ecosystems.
What Are The Main Uses Of Petroleum?
In America, in 2019, around 75 percent of petroleum is made into fuel, such as motor gasoline (45 percent), heating oil and diesel fuel (20 percent), and aviation fuel (8 percent). The remaining 27 percent is used for petrochemical feedstocks (used to make chemicals, synthetic rubber and plastics), waxes, lubricating oils and asphalt. Petroleum by-products are used in the manufacture of more than 6,000 items, ranging from: fertilizers, paint, detergents, tyres and refrigerators, to perfumes, soap, vitamins, deodorants, aspirin, heart valves, dentures, and cameras, to name but a few. 19
What is the difference between crude oil, petroleum and petroleum products?
“Crude oil” is a hydrocarbon-rich liquid of varying viscosity, which is drilled for or pumped out in-situ from underground rock formations, or surface mined from near surface formations. “Petroleum products” are all those products distilled from crude oil at petroleum refineries, or obtained from the extraction of liquid hydrocarbons at natural gas processing plants. “Petroleum” is sometimes used interchangeably with the term “oil”, although technically it includes both crude oil and petroleum-refined products.
What Is Tight Oil?
Tight oil is a form of crude oil found in impermeable shale and limestone rock formations. It’s crude oil that has gradually seeped upwards from the depths until it meets a layer of rock that doesn’t allow liquid to pass through it. Although it’s processed into gasoline, diesel, and aviation fuels, just like conventional oil, it’s extracted using hydraulic fracturing, or “fracking” techniques.
Fracking, a relatively new process, involves drilling vertically usually for an average of about 1.5 km (about 5,000 feet), before making a right-angle turn and drilling horizontally for maybe 2 km (6,500 feet) into oil bearing shale. Chemically treated water is then forced at very high pressure into the surrounding rock to create cracks, through which oil flows back up the drill to the surface. Proppants, typically sand or man-made ceramic materials, are added to the water to keep the cracks open when the pressure is released.
Fracking started as an experiment in 1947, and has been used in more than 3 million oil and gas wells around the world, a third of which are in America. 20 It needs significantly more energy than conventional drilling techniques, and involves higher greenhouse gas emissions, including higher emissions of natural gas. This is because natural gas is often released from the same rock formations and is typically burnt off or flared at the well site. Fugitive methane emissions are another problem. 21 See also: Why are Methane Levels Rising?
In addition, the heavy use of water during the fracturing process places significant pressure on local water supplies, and can create serious environmental challenges for operating companies when the used, polluted, water is returned into the local water system.
While tight oil fracking typically generates more emissions and more pollution than conventional oil sources, a growing share of oil is coming from tight oil resources, especially in the United States. The U.S. Energy Information Administration (EIA) estimates that, in 2019, about 7.76 million barrels per day of crude oil came from tight oil deposits. This was equal to about 63% of total U.S. crude oil production in 2019, more than two and a half times the 23 percent produced in 2011. 22
Globally, tight oil production is projected to double between 2015 and 2040. Most of the increase will come from the United States, with the rest coming from countries such as Russia, Canada, and Argentina. 23
Global Tight Oil Reserves
What Is Oil Shale?
Oil shale is a sedimentary rock containing kerogen from which liquid hydrocarbons can be produced, called shale oil. Shale oil (not to be confused with “tight oil”, a type of crude oil obtained from shale rock) is a lower grade substitute for conventional crude oil. Its extraction from oil shale is more costly than the production of conventional crude oil, both financially and environmentally. 25
Oil shale mining usually takes place above ground, using open pit or strip-mining techniques. Underground in-situ extraction of oil shale typically employs the room-and-pillar method. 26
The extracted oil shale can be burned directly in furnaces as a low-grade fuel for electrical power generation or heating, or used in chemical and construction-materials processing. 27 Usually, however, it is processed into shale oil. This is normally done off-site, although some newer technologies perform this on site. 28
Whether on- or off-site, processing involves using pyrolysis to break up the kerogen in the oil shale to synthetic crude oil and oil shale gas. Pyrolysis involves heating shale (in the absence of oxygen) to between 450°C (842°F) and 500°C (932°F), at which point the kerogen decomposes into gas, condensable oil, and a solid residue. 25 The synthetic crude oil can be used immediately as a fuel or enhanced by adding hydrogen and removing impurities such as sulfur and nitrogen.
According to a World Energy Council estimate, global deposits of oil shale amount to the equivalent of 6 trillion barrels of oil in place. 30
What Are the Main Alternatives to Fossil Fuels?
The principal alternatives to fossil fuels like petroleum (oil), are renewables such as: hydropower (hydroelectricity), wind power, natural biomass and biofuels, solar power, and geothermal energy. Marine energies like wave power and tidal power are still in development. Nuclear fusion remains somewhat futuristic.
What Is Tar Sands Oil?
Tar sands (“oil sands”) are another unconventional type of oil deposit. Tar sands consist of a mixture of sand, clay and water, laced with between 1 and 20 percent of bitumen, an extremely viscous semisolid form of petroleum, whose tar-like appearance gives the deposit its name. Bitumen itself is a mixture of carbon (83 percent), hydrogen (10.5 percent), oxygen (0.95 percent), nitrogen (0.36 percent) and sulfur (4.8 percent). Roughly two tons of tar sands are needed to produce one barrel of oil.
Other deposits of bitumen are located in numerous countries, with the largest reserves being found in Canada, Venezuela, Kazakhstan and Russia. Global reserves are estimated to be more than 2 trillion barrels, although not all of these resources are likely to be economically or technically recoverable. America’s reserves of tar sands oil are estimated at between 12 billion and 19 billion barrels.
How Is Tar Sands Oil Extracted?
There are two main extraction techniques: strip mining and in situ steam extraction. The former is used where oil deposits are within about 225 feet of the surface; steam extraction is used for anything deeper.
Strip mining starts with deforestation of the area involved. Surface layers of soil and trees are cleared, exposing the tar sands. These are then scooped out into huge trucks using giant shovels, and taken to an on-site processing facility. Here the oil sand is mixed with hot water and agitated until it separates into layers of bitumen, water and sand. The bitumen is then scooped off the top and thinned with light crude oil, allowing it to be sent by pipeline to an off-site upgrading plant where it is processed into synthetic crude oil. The water and sand are recycled. In Alberta, roughly 20 percent of tar sands oil is removed using open pit methods.
Steam extraction usually uses two wells. Both descend vertically before turning horizontally for up to 2 km. One well is used to pump steam into the deposit to heat the bitumen and make it flow more easily. The steam is sometimes left for days or even weeks to allow the heat to soak into the surrounding sandstone. The other well, often positioned at the bottom of the deposit, is used to recover the bituminous mixture and bring it to the surface. The mixture is duly processed into synthetic crude oil.
Pollution Caused by Tar Sands Mining Activities
Tar sands oil is more costly and complex to extract than conventional oil, and the industry’s flagship deposit in Alberta, Canada, happens to be located in the middle of boreal forest, drawing huge resistance from environmental groups for uprooting such a precious carbon-absorbing resource. The situation has been aggravated further by two things.
First, several tar sands oil companies have avoided millions of dollars’ worth of clean-up costs by filing for bankruptcy. 31 Second, relatively little clean-up has so far taken place, raising fears that at the end of the day Canadian taxpayers will have to foot the bill. So what might be the clean-up cost? According to Rob Wadsworth, Vice President of Closure and Liability for the official Alberta Energy Regulator (AER), the “worst case” cost of cleaning up the Alberta oil patch will be a eye-popping C$260 billion (US$195 billion). He said a “flawed system” of industrial oversight is to blame.
The size of Alberta’s tar sands operation is massive. Its tailings ponds alone – which contain a toxic residue of heavy metals and hydrocarbons from the bitumen separation process – are some of the biggest man-made structures on Earth – big enough to be seen from space. 32
Greenhouse Gas Emissions from Tar Sands Mining
According to Terry Abel, executive vice president of the Canadian Association of Petroleum Producers (CAPP), the average emissions per barrel of oil produced in the region have declined by roughly 30 percent since the early 1990s.
However, according to a recent scientific study published in Nature Communications, emissions from the Canadian oil sands, measured directly from aircraft, are about 30 percent higher than the figures reported by the industry. The results of the study show that CO2 emission intensities for Alberta’s tar sands facilities are 13–123 percent larger than those estimated using publicly available data. This leads to 64 percent higher annual greenhouse gas emissions from surface mining activities, and 30 percent higher overall OS greenhouse gas emissions (17 Mt) compared to that reported by industry. 33
According to Oil Change International (OCI), the research, communications, and advocacy organization, tar sands oil is more hazardous to move because it is more corrosive to pipelines. When accidents happen, as they inevitably do, it is more difficult to clean up a bituminous spill. For instance, the Kalamazoo River spill (July 2010) cost more per barrel to clean up than any spill in U.S. history up to that point. And even after two years of effort and hundreds of millions of dollars of clean up expenditure, oil still continued to pollute some parts of the affected area. 34
Environmental Concerns About Petroleum
The petroleum oil industry is responsible for a wide range of well-documented environmental problems. Drilling can cause air pollution as well as contamination of the local water supply. Where gas flaring occurs, methane (one of the most powerful greenhouse gases) is vented directly into the atmosphere. Gas flaring is a big problem in the Arctic.
The burning of petroleum in vehicles, for instance, causes a huge amount of air pollution through its emissions of toxic gases and tiny particles of black carbon (from incomplete combustion), which are a major contributor to urban smog around the world. In Asia, these emissions contribute to instances of regional toxic haze, such as the Asian Brown Cloud that appears over parts of the Indian sub-continent during the dry winter months. See: Health Effects of Air Pollution.
How Much Oil Do We Produce?
Total world oil production in 2019 averaged 100 million barrels per day. This includes crude oil, all other petroleum liquids and biofuels. 35
Which Countries Produce The Most Oil?
|Country||Million Barrels per Day||Share of World Total|
|United Arab Emirates||4.13||4%|
|Total Top 10||71.73||71%|
For an in-depth article on the consequences of using oil and other fossil fuels, see: What is Global Warming?
Which Countries Consume The Most Oil?
|Country||Million Barrels per Day||Share of World Total|
How Much Oil Do We Have Left?
According to BP’s Statistical Review of World Energy (2020), there were 1.73 trillion barrels of oil reserves in the world in 2019. This is sufficient to satisfy 50 years of demand at current production levels. The largest reserves are held by Venezuela, Saudi Arabia, and Canada. (Most Venezuelan and Canadian oil is tar sands oil.)
- “Global Oil & Gas Exploration & Production Industry – Market Research Report.” IBISWorld. May, 2019. For oil industry knowledge of climate change, see: “Early oil industry knowledge of CO2 and global warming.” B. Franta. Nature Clim Change 8, 1024–1025 (2018).
- IPCC. Special Report on Global Warming of 1.5°C. Summary for Policymakers. 2018.
- “Greenhouse Gas Emissions from a Typical Passenger Vehicle.” United States Environmental Protection Agency (EPA). March 2018.
- “The environmental impacts of cars, explained.” National Geographic.
- “Archaeomineralogy.” George Rapp. (1985). Springer. p.237.
- “The Oil Weapons.” Zayn Bilkadi. Saudi Aramco World. January–February 1995, pp. 20-7.
- “The Chinese Oil Industry: History and Future.” Feng, Lianyong; Hu, Yan; Hall, Charles A. S; Wang, Jianliang (2013). Springer. p.2. (2012)
- “Practical Advances in Petroleum Processing.” Samuel Hsu Chang, Paul R.Robinson. 1. Springer. p.2. (2006)
- “Of Lamps and Whales.” John H. Lienhard. University of Houston. uh.edu/
- “Titusville, Pennsylvania.” World Digital Library. wdl.org/
- “Edison: a Life of Invention.” Paul Israel (1998). Wiley. p.186
- “Automobile History.” Aug 21, 2018. History.com
- “The Age of Oil: The Mythology, History, and Future of the World’s Most Controversial Resource.” Leonardo Maugeri. Globe Pequot, 2007, p.15.
- “U.S. energy facts explained.” U.S. Energy Information Administration. EIA. August 28, 2019.
- “The Motor Men.” Peter King. Quiller Press. (1989)
- “How many gallons of gasoline and diesel fuel are made from one barrel of oil?” FAQs. U.S. Energy Information Administration (EIA)
- “Shaky industry that runs the world”. Ian Mann The Times, South Africa. 24 January 2010.
- “The world’s biggest oil and gas companies.” Offshore Technology. March 19, 2019.
- “What are petroleum products, and what is petroleum used for?” U.S. Energy Information Administration. EIA. September 2020.
- “Hydraulic fracturing 101.” George E. King. (PDF) Society of Petroleum Engineers, SPE 152596. 2012.
- “What is Tight Oil?” Union of Concerned Scientists. Aug 2, 2016.
- “How much shale (tight) oil is produced in the United States?” U.S. Energy Information Administration (EIA). Sept, 2020.
- “World tight oil production to more than double from 2015 to 2040.” U.S. Energy Information Administration (EIA). Aug 12, 2016.
- “Technically recoverable tight oil reserves worldwide as of 2016, by country.” Statista. 2019.
- “Shale Oil – The Elusive Energy.” (PDF) Walter Youngquist. (1998) Hubbert Center Newsletter. Colorado School of Mines .
- “Oil Shale Development in the United States. Prospects and Policy Issues.” Bartis, James T. et al; (2005). National Energy Technology Laboratory of the U.S. Department of Energy (PDF). RAND Corporation.
- “Geology and resources of some world oil shale deposits” (PDF). John R. Dyni. (2006). Scientific Investigations Report 2005–5294. United States Department of the Interior, United States Geological Survey.
- “Comparison of the Acceptability of Various Oil Shale Processes.” (PDF). Burnham, Alan K.; McConaghy, James R. 26th Oil Shale Symposium. Golden, Colorado: Lawrence Livermore National Laboratory. UCRL-CONF-226717. (October 2006).
- “Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-like Shale Oil” (PDF). A. K. Burnham. (20 August 2003). Lawrence Livermore National Laboratory. UCRL-ID-155045.
- “World energy resources. Oil 2016.” (PDF). World Energy Council. ISBN 978-0-946121-62-5.
- “Oil firm ceasing operations, leaving thousands of untended Alberta wells.” CBC News via The Canadian Press. 8 March 2018.
- “This is the world’s most destructive oil operation—and it’s growing.” Stephen Leahy. National Geographic. April 11, 2019.
- “Measured Canadian oil sands CO2 emissions are higher than estimates made using internationally recommended methods.” John Liggio, Shao-Meng Li et al. Nature Communications Volume 10, Article number: 1863 (2019)
- “No KXL.” Oil Change International (OCI) priceofoil.org/
- U.S. Energy Information Administration. “What countries are the top producers and consumers of oil?” Dec. 6, 2020