Environmental impact of the petroleum industry
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Petroleum has many uses, and the environmental impact of the petroleum industry is correspondingly extensive and expansive. Crude oil and natural gas are primary energy and raw material sources that enable numerous aspects of modern daily life and the world economy. Their supply has grown quickly over the last 150 years to meet the demands of rapidly increasing human population, creativity, and consumerism.
Substantial quantities of toxic and non-toxic waste are generated during the extraction, refinement, and transportation stages of oil and gas. Some industry by-products, such as volatile organic compounds, nitrogen & sulfur compounds, and spilled oil can pollute air, water, and soil at levels that are harmful to life where improperly managed. Climate warming, ocean acidification, and sea level rise are global changes enhanced by the industry's emissions of greenhouse gases like methane and micro-particulate aerosols like black carbon.
Among all human activities, fossil-fuel extraction is the largest contributor to the ongoing buildup of carbon compounds in the earth's biosphere. The International Energy Agency and others report that oil & gas use comprised over 55% (18 Billion Tons) of the record 32.8 Billion Tons (BT) of carbon dioxide (CO2) released into the atmosphere from all energy sources during year 2017. Coal use comprised the remaining 45%. Total emissions continue to rise nearly every year: up another 1.7% to 33.1 BT in year 2018.
Through its own operations, the petroleum industry directly contributed about 8% (2.7 BT) of the 32.8 BT year 2017 total of CO2 from fossil fuels. Also, due to its intentional and other releases of natural gas, the industry directly contributed at least 79 Million Tons of methane (2.4 BT CO2-equivalent) that same year; an amount equal to about 14% of all known anthropogenic and natural emissions of the potent warming gas. Since the industrial age began circa 1750–1850 with growing wood and coal use, the atmospheric concentration of carbon dioxide and methane have increased about 50% and 150%, respectively, above their relatively stable levels of the prior 800,000+ years.  Each is currently increasing at a rate of about 1% every year, since about half of the added carbon is absorbed by the world's oceans. The acceleration is also so rapid that half of all emissions and buildup have occurred over just the past 30 years.
Along with fuels like gasoline and liquified natural gas, petroleum enables many consumer chemicals and products, such as fertilizers and plastics. Most alternative technologies for energy generation, transportation, and storage can only be realized at this time because of its diverse usefulness. Conservation, efficiency, and minimizing waste impacts of petroleum products are effective industry and consumer actions toward achieving better environmental sustainability.
Petroleum is a complex mixture of many components . These components include straight chained, branched, cyclic, monocyclic aromatic and polycyclic aromatic hydrocarbons. The toxicity of oils can be understood using the toxic potential or the toxicity of each individual component of oil at the water solubility of that component. There are many methods that can be used to measure the toxicity of crude oil and other petroleum related products. Certain studies analyzing levels of toxicity can use the target lipid model or colorimetric analysis using colored-dyes in order to assess toxicity and biodegradability.
Different oils and petroleum-related products have different levels of toxicity. Levels of toxicity are influenced by many factors such as weathering, solubility, as well as chemical properties such as persistence. Increased weathering tends to decrease levels of toxicity as more soluble and lower molecular weight substances are removed. Highly soluble substances tend to have higher levels of toxicity than substances that are not very soluble in water. Generally oils that have longer carbon chains and with more benzene rings have higher levels of toxicity. Benzene is the petroleum-related product with the highest level of toxicity. Other substances other than benzene which are highly toxic are toluene, methylbenzene and xylenes (BETX). Substances with the lowest toxicity are crude oil and motor oil.
Despite varying levels of toxicity amongst different variants of oil, all petroleum -derived products have adverse impacts on human health and the ecosystem. Examples of adverse effects are oil emulsions in digestive systems in certain mammals might result in decreased ability to digest nutrients that might lead to death of certain mammals. Further symptoms include capillary ruptures and hemorrhages. Ecosystem food chains can be affected due to a decrease in algae productivity therefore threatening certain species. Oil is "acutely lethal" to fish - that is, it kills fish quickly, at a concentration of 4000 parts per million (ppm) (0.4%). The toxicity of petroleum related products threaten human health. Many compounds found in oil are highly toxic and can cause cancer (carcinogenic) as well as other diseases. Studies in Taiwan link proximity to oil refineries to premature births. Crude oil and petroleum distillates cause birth defects.
Benzene is present in both crude oil and gasoline and is known to cause leukaemia in humans. The compound is also known to lower the white blood cell count in humans, which would leave people exposed to it more susceptible to infections. "Studies have linked benzene exposure in the mere parts per billion (ppb) range to terminal leukemia, Hodgkin's lymphoma, and other blood and immune system diseases within 5-15 years of exposure."
Fossil gas and oil naturally contain small amounts of radioactive elements which are released during mining. High concentration of these elements in brine is a technological and environmental concern.
Petroleum extraction disrupts the equilibrium of earth's carbon cycle by transporting sequestered geologic carbon into the biosphere. The carbon is used by consumers in various forms and a large fraction is combusted into the atmosphere; thus creating massive amounts of the greenhouse gas, carbon dioxide, as a waste product. Natural gas (mostly methane) is an even more potent greenhouse house when it escapes into the atmosphere prior to being burned.
Petroleum has enabled plastics to be used to create a wide range and massive quantity of consumer items at extremely low production costs. Single-use plastics and improper disposal are common. The majority of plastic is not recycled, and it fragments into smaller and smaller pieces over time. Microplastics are observable in air, water, and soil samples gathered from nearly every location on earth's surface, and also increasingly within biological samplings. Long-term effects from the environmental buildup of plastic waste are under scientific evaluation but thus far mostly unknown. 
Local and regional impacts
Some harmful impacts of petroleum can be limited to the geographic locations where it is produced, consumed, and/or disposed. In many cases, the impacts may be reduced to safe levels when consumers practice responsible use and disposal. Producers of specific products can further reduce the impacts through life cycle assessment and environmental design practices.
Emissions from the petroleum industry occur in every chain of the oil-producing process from the extraction to the consumption phase . In the extraction phase, gas venting and flaring release not only methane and carbon dioxide, but various other pollutants like nitrous oxides and aerosols. Certain by-products include carbon monoxide and methanol. When oil or petroleum distillates are combusted, usually the combustion is not complete and the chemical reaction leaves by-products which are not water or carbon dioxide. However, despite the large amounts of pollutants, there is variation in the amount and concentration of certain pollutants. In the refinement stages of petroleum also contributes to large amounts of pollution in urban areas. This increase in pollution has adverse effects on human health due to the toxicity of oil. A study investigating the effects of oil refineries in Taiwan. The study found an increased occurrence of premature births in mothers that lived in close proximity to oil refineries than mothers who lived away from oil refineries. There were also differences observed in sex ratios and the birth weight of the children. Also, fine particulates of soot blacken humans' and other animals' lungs and cause heart problems or death. Soot is cancer causing (carcinogenic)
Volatile organic compounds (VOCs) are gases or vapours emitted by various solids and liquids." Petroleum hydrocarbons such as gasoline, diesel, or jet fuel intruding into indoor spaces from underground storage tanks or brownfields threaten safety (e.g., explosive potential) and causes adverse health effects from inhalation.
The combustion process of petroleum , coal , and wood is responsible for increased occurrence of acid rain. Combustion causes an increased amount of nitrous oxide s, along with sulfur dioxide from the sulfur in the oil. These by-products combine with water in the atmosphere to create acid rain. The increased concentrations of nitrates and other acidic substances have significant effects on the pH levels of rainfall. Data samples analyzed from the United States and Europe from the past 100 years and showed an increase in nitrous oxide emissions from combustion. The emissions were large enough to acidify the rainfall. The acid rain has adverse impacts on the larger ecosystem. For example, acid rain can kill trees, and can kill fish by acidifying lakes. Coral reefs are also destroyed by acid rain. Acid rain also leads to the corrosion of machinery and structures (large amounts of capital) and to the slow destruction of archeological structures like the marble ruins of Rome and Greece.
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is usually applied to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of crude oil from tankers, pipelines, railcars, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.
Major oil spills include, Lakeview Gusher, Gulf War oil spill, and the Deepwater Horizon oil spill. Spilt oil penetrates into the structure of the plumage of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Other factors influencing the rate of long-term contamination is the continuous inputs of petroleum residues and the rate at which the environment can clean itself Spills may take weeks, months or even years to clean up.
Waste oil is oil containing not only breakdown products but also impurities from use. Some examples of waste oil are used oils such as hydraulic oil, transmission oil, brake fluids, motor oil, crankcase oil, gear box oil and synthetic oil. Many of the same problems associated with natural petroleum exist with waste oil. When waste oil from vehicles drips out engines over streets and roads, the oil travels into the water table bringing with it such toxins as benzene. This poisons both soil and drinking water. Runoff from storms carries waste oil into rivers and oceans, poisoning them as well.
The combustion of petroleum causes an increased amount of carbon dioxide emissions as well as other greenhouse gases. One of the first studies on the effects of carbon dioxide on climate was in the late 1800s by Swedish Nobel chemist Svante Arrhenius. His mathematical model showed that an increase of carbon dioxide results in an increase in surface temperatures. The science has further advanced since then, and the IPCC (2007) states that earth's climate system will heat up by 3 degrees Celsius for a doubling of carbon dioxide. Such warming of the temperatures will have massive impacts on rainfall patterns, retreat of glaciers, and the average sea levels.
A fraction of the added greenhouse gases are absorbed by the oceans to form carbonic acid. The increased acidity contributes to coral bleaching and acts more generally to disrupt seashell formation. Ocean warming is also driving the migration of mobile marine life towards the polar regions.
Modern human societies utilize cheap and abundant energy to promote economic growth and maintain political stability. Government's and economic institutions around the world lower prices and increase supplies of fossil fuels for both consumers and producers by providing various forms of financial support to the industry. These include such traditional subsidies as direct payments, tax preferences, depletion allowances, research & development grants, and the removal of existing environmental protections. Considering all forms of support, the largest assistance to fossil fuels arises from the failure of governments to pass along most costs from the environmental and human-health impacts of the waste.
Accounting by the International Energy Agency and OECD indicates that traditional subsidies throughout the world amounted to about $400-600 Billion annually during years 2010–2015, and remained near $400 Billion in year 2018 with 40% going to oil. By comparison, a working group at the International Monetary Fund estimates that all support to the fossil-fuel industry totaled about $5.2 Trillion (6.4% of global gross domestic product) during year 2017. The largest subsidizers were China, the United States, Russia, the European Union, and India which together accounted for about 60% of the total.
According to the theory of ideal market competition, accurate prices could act to drive more responsible industry and consumer choices that reduce waste and long-term scarcity. Eliminating subsidies to restore accurate prices would have their most direct effects from the supply side of the industry. By contrast, the objective of some carbon tax and carbon trading mechanisms is to restore pricing accuracy from the consumption side.
Conservation and phasing out
Many countries across the World have subsidies and policies designed to reduce the use of petroleum and fossil fuels. Examples include China which switched from providing subsidies for fossil fuels to providing subsidies for renewable energy. Other examples include Sweden which created laws which are designed to eventually phase out the use of petroleum, which is known as the 15-year plan. These policies have their benefits and their challenges and every country has had their different experiences. In China, positive benefits were observed in the energy system due to higher renewable energy subsidies in three ways. It made consumption of energy cleaner due to moving for cleaner sources. Secondly, it helped increase the efficiency and third it resolved the issue of imbalanced distribution and consumption. However, from the Chinese experience, there were challenges observed. These challenges included economic challenges like initially lower economic benefits for subsidies from renewable energy than for oil. Other challenges included a high cost of research and development, the uncertainty of cost and potentially high-risk investments. These factors make the development of renewable energy very dependent on government support. However, aims of phasing out fossil fuels and petroleum use may also present economic benefits such as increased investment. This strategy may help achieve social goals for example reduction in pollution which might translate to better environmental and health outcomes.
Another option for conserving energy and phasing out petroleum use is adopting new technologies in order to increase efficiency. This can include changing production methods and modes of transportation.
Substitution of other energy sources
Alternatives to petroleum can include using other “cleaner” energy sources such as renewable energy, natural gas or biodiesel. Some of the alternatives have their strengths and limitations that might impact on the possibility of adopting them in the future.
Using corn-based ethanol might be an alternative to using petroleum. However, studies that concluded that corn-based ethanol uses less net energy do not factor in the co-products of production. Current corn-ethanol technologies are much less petroleum intensive than gasoline however have the GHG emission levels similar to gasoline. The literature is mainly unclear what the GHG emission changes would be by adopting corn-based ethanol for biodiesel. Some studies report a 20% increase in GHG emissions and some report a 32% decrease. However, the actual number might be a 13% decrease in GHG emissions which is not a significant decrease. The future of biodiesel might be adopting cellulose ethanol technology to produce biodiesel as that technology will contribute to a decrease in emissions.
Renewable energy alternatives also exist. These include solar energy, wind energy, geothermal and hydroelectricity as well as other sources. These sources are said to have much lower emissions, and almost minimal secondary by products. The production of renewable energy is projected to grow in nearly every region in the World. Natural gas is also seen as a potential alternative to oil. Natural gas is much cleaner than oil in terms of emissions. However natural gas has its limitation in terms of mass production. For example, in order to switch from crude oil to natural gas there are technical and network changes that need to occur before the implementation can be complete. Two possible strategies are to first develop the end use technology first or second is to completely change the fuel infrastructure.
Use of biomass instead of petroleum
Biomass is becoming a potential option as a substitute for petroleum. This is due to the increased environmental impacts of petroleum and the desire to reduce the use of petroleum. Potential substitutes include cellulose from fibrous plant materials as a substitute for oil-based products. Plastics can be created by cellulose instead of oil and plant fat can be substituted for oil to fuel cars. In order for biomass to succeed there needs to be an integration of different technologies to different biomass feedstock in to produce different bioproducts. Incentives for biomass are a decrease of carbon dioxide, need for a new energy supply and need to revitalize rural areas.
There is also the potential to implement many technologies as safety measures to mitigate safety and health risks of the petroleum industry. These include measures to reduce oil spills, false floors to prevent gasoline drips in the water table and double-hulled tanker ships. A relatively new technology that can mitigate air pollution is called bio-filtration. Bio filtration is where off-gasses that have biodegradable VOCs or inorganic air toxins are vented out through a biologically active material. This technology successfully used in Germany and the Netherlands mainly for odor control. There are lower costs and environmental benefits include low energy requirements
- Arctic Refuge drilling controversy
- Environmental impact of the oil shale industry
- Environmental impact of the petroleum industry in Nigeria
- Environmental impact of hydraulic fracturing
- Energy and the environment
- Environmental issues of oil sands
- List of environmental issues
- Peak oil
- The Library of Congress (2006). "History of the Oil and Gas Industry". Business and Economics Research Advisor (5/6).
- "EPA enforcement targets flaring efficiency violations" (PDF). U.S. Environmental Protection Agency. 2012-08-01. Retrieved 2020-02-08.
- "Frequent, routine flaring may cause excessive, uncontrolled sulfur dioxide releases" (PDF). U.S. Environmental Protection Agency. 2000-10-01. Retrieved 2020-02-08.
- Bautista H. and Rahman K. M. M. (2016). Review On the Sundarbans Delta Oil Spill: Effects On Wildlife and Habitats. International Research Journal, 1(43), Part 2, pp: 93–96. doi:10.18454/IRJ.2016.43.143
- Bautista, H.; Rahman, K. M. M. (2016). "Effects of Crude Oil Pollution in the Tropical Rainforest Biodiversity of Ecuadorian Amazon Region". Journal of Biodiversity and Environmental Sciences. 8 (2): 249–254.
- Eggleton, Tony (2013). A Short Introduction to Climate Change. Cambridge University Press. p. 52. ISBN 9781107618763.
- Stohl, A.; Klimont, Z.; Eckhardt, S.; Kupiainen, K.; Chevchenko, V.P.; Kopeikin, V.M.; Novigatsky, A.N. (2013), "Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions", Atmos. Chem. Phys., 13 (17): 8833–8855, Bibcode:2013ACP....13.8833S, doi:10.5194/acp-13-8833-2013
- Michael Stanley (2018-12-10). "Gas flaring: An industry practice faces increasing global attention" (PDF). World Bank. Retrieved 2020-02-08.
- Heede, R. (2014). "Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010". Climatic Change. 122: 229–241. doi:10.1007/s10584-013-0986-y.
- "Data and Statistics: CO2 emissions by energy source, World 1990-2017". International Energy Agency (Paris). Retrieved 2020-02-09.
- Hannah Ritchie and Max Roser (2020). "CO₂ and Greenhouse Gas Emissions: CO₂ Emissions by Fuel". Our World In Data. Published online at OurWorldInData.org. Retrieved 2020-02-09.
- "Global Energy & CO2 Status Report 2019: The latest trends in energy and emissions in 2018". International Energy Agency (Paris). 2019-03-01. Retrieved 2020-02-09.
- "Methane Tracker - Methane from oil and gas". International Energy Agency (Paris). 2020-01-01. Retrieved 2020-02-09.
- "Tracking Fuel Supply - Methane emissions from oil and gas". Internation Energy Agency (Paris). 2019-11-01. Retrieved 2020-02-09.
- Alvarez, R.A.; et al. (2018-07-13). "Assessment of methane emissions from the U.S. oil and gas supply chain". Science. 361 (6398): 186–188. Bibcode:2018Sci...361..186A. doi:10.1126/science.aar7204. PMC 6223263. PMID 29930092.
- "Methane Tracker - Country and regional estimates". Internation Energy Agency (Paris). 2019-11-01. Retrieved 2020-02-09.
- "Methane Tracker - Analysis". Internation Energy Agency (Paris). 2019-11-01. Retrieved 2020-02-09.
- Hannah Ritchie and Max Roser (2020). "CO₂ and Greenhouse Gas Emissions: CO₂ Concentrations". Our World In Data. Published online at OurWorldInData.org. Retrieved 2020-02-09.
- Hannah Ritchie and Max Roser (2020). "CO₂ and Greenhouse Gas Emissions: CH4 Concentrations". Our World In Data. Published online at OurWorldInData.org. Retrieved 2020-02-09.
- Eggleton, Tony (2013). A Short Introduction to Climate Change. Cambridge University Press. p. 153. ISBN 9781107618763.
- Vaclav Smil (2016-02-29). "To Get Wind Power You Need Oil". IEEE Spectrum. Retrieved 2020-02-09.
- Amory Lovins (2018-09-18). "How big is the energy efficiency resource?". Environmental Research Letters. IOP Science. 13 (9). doi:10.1088/1748-9326/aad965.
- Di Toro, Dominic M.; McGrath, Joy A.; Stubblefield, William A. (2007-01-01). "Predicting the toxicity of neat and weathered crude oil: Toxic potential and the toxicity of saturated mixtures" (PDF). Environmental Toxicology and Chemistry. 26 (1): 24–36. doi:10.1897/06174r.1. ISSN 1552-8618. PMID 17269456.
- Montagnolli, Renato Nallin; Lopes, Paulo Renato Matos; Bidoia, Ederio Dino (2015-02-01). "Screening the Toxicity and Biodegradability of Petroleum Hydrocarbons by a Rapid Colorimetric Method". Archives of Environmental Contamination and Toxicology. 68 (2): 342–353. doi:10.1007/s00244-014-0112-9. ISSN 0090-4341. PMID 25537922.
- Prasad, M. S.; Kumari, K. (1987). "Toxicity of Crude Oil to the Survival of the Fresh Water FishPuntius sophore (HAM.)". Acta Hydrochimica et Hydrobiologica. 15: 29–36. doi:10.1002/aheh.19870150106.
- Lin, Meng-Chaio; Chiu, Hui-Fen; Yu, Hsin-Su; Tsai, Shang-Shyue; Cheng, Bi-Hua; Wu, Trong-Neng; Sung, Fung-Sung; Yang, Chun-Yuh (2001). "Increased Risk of Preterm Deliveries in Areas with Air Pollution From a Petroleum Refinery Plant in Taiwan". Journal of Toxicology and Environmental Health Part A. 64 (8): 637–644. doi:10.1080/152873901753246232. PMID 11766170.
- "Petroleum Solvents Overview". www.burke-eisner.com.
- Kirkeleit, J.; Riise, T.; Bråtveit, M.; Moen, B. E. (2005). "Benzene Exposure on a Crude Oil Production Vessel -- KIRKELEIT et al. 50 (2): 123 -- Annals of Occupational Hygiene". The Annals of Occupational Hygiene. 50 (2): 123–9. doi:10.1093/annhyg/mei065. PMID 16371415. Retrieved 2010-06-07.
- "Benzene pollution - a health risk in Gulf BP Oil drilling disaster - La Leva di Archimede (ENG)". www.laleva.org. Retrieved 2010-06-07.
- "The Syrian Job: Uncovering the Oil Industry's Radioactive Secret". DeSmog UK. Retrieved 2020-05-19.
- SAPEA (Scientific Advice for Policy by European Academies) (2019). A scientific perspective on microplastics in nature and society. https://www.sapea.info/topics/microplastics/: SAPEA (Scientific Advice for Policy by European Academies). ISBN 978-3-9820301-0-4.
- Tuccella, P.; Thomas, J. L.; Law, K. S.; Raut, J.-C.; Marelle, L.; Roiger, A.; Weinzierl, B.; Gon, H. A. C. Denier van der; Schlager, H. (2017-06-07). "Air pollution impacts due to petroleum extraction in the Norwegian Sea during the ACCESS aircraft campaign". Elem Sci Anth. 5: 25. doi:10.1525/elementa.124. ISSN 2325-1026.
- HDOH. "Field Investigation of the Chemistry and Toxicity of TPH in Petroleum Vapors: Implications for Potential Vapor Intrusion Hazards". Hawai'i Department of Health. Retrieved 8 December 2012.
- U.S.EPA (11 June 2015). "Vapor Intrusion". U.S.EPA. Retrieved 13 June 2015.
- Brimblecombe, P.; Stedman, D.H (1982). "Historic Evidence of Dramatic Increase in Nitrate Component of Acid Rain". Nature. 298: 460–463. doi:10.1038/298460a0. hdl:2027.42/62831.
- Lingering Lessons of the Exxon Valdez Oil Spill Archived June 13, 2010, at the Wayback Machine
- Nicodem, David E.; Fernandes, Conceicao; Guedes, Carmen L.B; Correa, Rodrigo J. (1997). "Photochemical processes and the environmental impact of petroleum spills". Biogeochemistry. 39 (2): 121–138. doi:10.1023/A:1005802027380.
- "Hindsight and Foresight, 20 Years After the Exxon Valdez Spill". NOAA Ocean Media Center. 2010-03-16. Retrieved 2010-04-30.
- State of Maine (www.maine.gov)
- Ramanathan, V.; Feng, Y. (2009). "Air pollution, greenhouse gases and climate change: Global and regional perspectives". Atmospheric Environment. 43 (1): 37–50. Bibcode:2009AtmEn..43...37R. doi:10.1016/j.atmosenv.2008.09.063.
- Paul Davidson (2015-04-14). "IMF: Low oil prices will spur global economy". USA Today. Retrieved 2020-02-15.
- Hana Vizcarra and Robin Just. "EPA VOC and Methane Standards for Oil and Gas Facilities". Harvard Law - Environmental & Energy Law Program. Retrieved 2020-02-08.
- David Cody; et al. (2019-05-02). "Global Fossil Fuel Subsidies Remain Large: An Update Based on Country-Level Estimates". International Monetary Fund. Retrieved 2020-02-11.
- Jocelyn Temperly (2018-02-28). "OECD: Fossil fuel subsidies added up to at least $373bn in 2015". CarbonBrief.org. Retrieved 2020-02-15.
- Wataru Matsumura and Zakia Adam (2019-06-13). "Fossil fuel consumption subsidies bounced back strongly in 2018". International Energy Agency. Retrieved 2020-02-15.
- Umair Irfan (2019-05-19). "Fossil fuels are underpriced by a whopping $5.2 trillion". vox.com. Retrieved 2020-02-11.
- Teresa Hartmann (2017-09-28). "How does carbon trading work". World Economic Forum. Retrieved 2020-02-11.
- Ouyang, Xiaoling; Lin, Boqiang (2014). "Impacts of increasing renewable energy subsidies and phasing out fossil fuel subsidies in China". Renewable and Sustainable Energy Reviews. 37: 933–942. doi:10.1016/j.rser.2014.05.013.
- Article on Sweden's Phasing Out of Petrol Use (www.guardian.co.uk)
- Farrell, Alexander E.; Plevin, Richard J.; Turner, Brian T.; Jones, Andrew D.; O'Hare, Michael; Kammen, Daniel M. (2006). "Ethanol Can Contribute to Energy and Environmental Goals". Science. 311 (5760): 506–508. Bibcode:2006Sci...311..506F. doi:10.1126/science.1121416. JSTOR 3843407. PMID 16439656.
- Panwar, N.L.; Kaushik, S.C.; Kothari, Surendra (2011). "Role of renewable energy sources in environmental protection: A review". Renewable and Sustainable Energy Reviews. 15 (3): 1513–1524. doi:10.1016/j.rser.2010.11.037.
- Chong, Zheng Rong; Yang, She Hern Bryan; Babu, Ponnivalavan; Linga, Praveen; Li, Xiao-Sen (2016). "Review of natural gas hydrates as an energy resource: Prospects and challenges". Applied Energy. 162: 1633–1652. doi:10.1016/j.apenergy.2014.12.061.
- Hekkert, Marko P.; Hendriks, Franka H.J.F.; Faaij, Andre P.C.; Neelis, Maarten L. (2005). "Natural gas as an alternative to crude oil in automotive fuel chains well-to-wheel analysis and transition strategy development". Energy Policy. 33 (5): 579–594. doi:10.1016/j.enpol.2003.08.018.
- Cherubini, Francesco (2010). "The biorefinery concept: Using biomass instead of oil for producing energy and chemicals". Energy Conversion and Management. 51 (7): 1412–1421. doi:10.1016/j.enconman.2010.01.015.
- Leson, Gero; Winer, Arthur (1991). "Bio filtration : An Innovative Air Pollution Control Technology for VOC emissions". Journal of Air and Waste Management Association. 41 (8): 1045–1054. doi:10.1080/10473289.1991.10466898.
- Information about petroleum spills in water from the State of New Department of Environmental Protection
- Safety Data Sheet -- Crude Oil (fscimage.fishersci.com)
- Beyond Katrina: Disaster on the Gulf Coast Continues --- 2010 Gulf of Mexico Oil Spill News, Information & Resources, 2008 Mississippi River Oil Spill Coverage