Petroleum (sometimes referred to as crude oil or simply “oil”) is a fossil fuel that was formed in the Earth’s crust from the remains of plants and marine organisms. Oil, as a source of energy and for chemical synthesis, is critical for the technological and economic growth in the world. Although oil is a finite resource, new sources continue to be discovered. Oil has high energy density and is chemically complex, making it suitable for multiple uses. Although it is available in large quantities in many parts of the world, in recent decades global attention has turned to reducing greenhouse gas emissions, and alternative energy sources are also being discovered, developed, and scaled to play larger roles in the global energy economy. Even with an expanding portfolio of energy sources and the global movement toward decarbonization, oil will remain part of the energy and petrochemical mix until other alternatives are available at sufficient scale and are cost competitive. The pace of transition will depend on many factors including government policies and regulatory developments.
In some cases, oil naturally finds its way into the sea through fissures and faults. Often, while the collective volumes are large, individual seeps generally release petroleum slowly enough over hundreds to thousands of years to allow surrounding organisms to avoid, adapt to, and, in some instances, even thrive in their presence (NRC, 2003). In other cases, oil finds its way into the sea in less intrinsic ways, due to anthropogenic activities such as exploration, production, and global transport of oil. Oil is transported many miles through subsea pipelines and on transport vessels to support global fossil fuel demands as well as more general consumer needs.
Oil as it exists naturally in our environment does not always lead to damaging effects. However, oil present in locations, concentrations, timespans, or molecular forms outside its natural existence presents a different story. Recognizing the sources, quantities, and composition of natural and anthropogenic inputs of oil into the sea, and understanding the fate and effects of that oil in the marine environment, are important in order to minimize potential impacts. The application of this knowledge provides the mechanisms to evaluate and respond to potential environmental impacts of oil on ocean ecosystems and move toward a restorative state following both chronic and human-caused episodic events.
Oil is encountered in a variety of forms in daily life. Crude oil and other hydrocarbon liquids are refined into petroleum products used for many different purposes: to power vehicles, heat buildings, lubricate parts, and produce electricity. The petrochemical industry uses petroleum as a raw material, or feedstock, for a long list of products; these products represent important contributions to modern societal needs and wants. As energy reliance shifts to alternative sources, it is not clear how production of petroleum for these other uses may change, but consumption of hydrocarbons for purposes other than energy is small relative to energy use. The U.S. Energy Information Administration (EIA) estimates that the non-combustion uses of fossil fuels account for approximately 7% of total fossil fuel consumption in the United States,1 and the International Energy Agency (IEA) estimates non-energy use of oil at approximately 17% and natural gas at approximately 12% globally (IEA, 2021a). Therefore, energy consumption is the main driver for the current and future demand of petroleum.
1.1 PRESENT AND FUTURE ENERGY NEEDS
1.1.1 World Energy Needs
World energy supply and demand was steadily growing until 2020, when the COVID-19 pandemic resulted in lockdowns and travel restrictions and, consequently, a drop in energy consumption. Following the reduction in demand,
1 See www.eia.gov, “Today in Energy,” April 6, 2018.
production of worldwide crude oil and natural gas liquids dropped ~7% from 4,617 million tonnes in 2019 to 4,296 million tonnes in 2020 (IEA, 2021).
In 2019, oil and natural gas represented more than 50% of all energy supply and, with the addition of coal, the total hydrocarbon share was 80% of the worldwide energy supply (see Figure 1.1).
In 2020, the United States remained the top producer of both oil and natural gas. Other top oil producers were Russia, Saudi Arabia, Canada, and the United Arab Emirates, and the top natural gas producers were Russia, Iran, China, and Canada (IEA, 2021).
Transportation is the largest consumer of oil globally, using 56% of the total energy share in 2019 (see Figure 1.2).
Industry and residential use are the largest consumers of natural gas, accounting for 67% of total in 2019 (see Figure 1.3).
The global energy landscape has been reconfigured considerably since the publication of Oil in the Sea III in 2003. A major driver for the change has been increased shale oil and gas production in the United States. Offshore oil and gas production share of the total oil and gas production has been declining (see Figure 3.18). Deep-water exploration is expected to further decline as the energy companies’ investment strategies adapt to shifting energy requirements driven by decarbonization efforts.
The worldwide marine transportation flows have changed as a result of U.S. shale production, increased Asian demand, and the introduction of new refinery locations, mainly in the Middle East and Asia. Figures 1.4 and 1.5 illustrate the complex global flows of oil and gas.
1.1.2 Energy Needs of North America
Petroleum is currently the largest North American energy source. As reported in the BP Statistical Review of World Energy (BP, 2021), in 2020 North American petroleum consumption averaged about 20.77 million barrels per day (bbl/d), or 2,967 tonnes per day (t/d). This was the lowest consumption rate since 1995 and the largest annual decrease in petroleum demand on record.2 This anomaly can be attributed to the COVID-19 pandemic and is not necessarily reflective of the current trend. The annual differences were most pronounced in jet fuel, which decreased by 40% from 2019 to 2020. For this reason, 2019 numbers (from BP, 2020) are discussed in this section. In 2019, North American petroleum consumption averaged about 23.54 million bbl/d (3,362 t/d), with the transportation sector (including gasoline, distillate fuel, HGLs, and jet fuel) accounting for the largest share (68%) of U.S. petroleum consumption. The breakdown by sector for the United States is shown in Figure 1.6.
In North America, the most consumed petroleum product is gasoline (42% of total consumption), followed by distillate fuel oil (23% of total consumption), hydrocarbon gas liquids (HGLs) (18% of total consumption), and then jet fuel (6% of total consumption). Distillate fuel oil includes both diesel fuel (used to power farming and construction equipment, boats, trucks, trains, generators, etc.) and heating oil (used for residential and commercial heating and for producing energy in power plants). HGLs include propane, butane, ethane, and others used in the production of plastics, cooking fuel, lighter fuel, and in gasoline.3
1.1.3 Energy Outlook
The global energy demand continues to grow due to the population growth and the improving standard of living around the world (see Figure 1.7). The biggest increase in demand is predicted in Asia (EIA, 2019).
At the same time that global energy demand is increasing, societal concern over climate change is driving decarbonization efforts around the world to reduce greenhouse gas emissions. The need for a decarbonized future to mitigate the potential future financial and human costs of climate change is well accepted globally (IPCC, 2021). The transition from the current energy production, consumption, and transport to the decarbonized future is challenging to imagine, and equally challenging to forecast. To capture the breadth of
2 See www.eia.gov, “Monthly Energy Review,” April 2022.
3 See https://www.eia.gov/energyexplained/oil-and-petroleum-products/use-of-oil.php.
future possibilities, Greene Economics (2021) considered three different projections:
- The Reference case, or business-as-usual scenario: Continuation of current trends.
- The Net Zero by 2050 (NZ2050) case: Reducing global carbon dioxide (CO2) emissions to net zero by 2050 is consistent with efforts to limit the long-term increase in average global temperatures to 1.5°C. (IEA, 2021b).
- Partial Transition: Halfway point between the Reference case and the NZ2050 case (ABS, 2020).
The share of oil and gas as the energy source globally differs considerably among the three scenarios (see Figure 1.8). In all scenarios, renewables have the largest rate of growth.
The following figures illustrate the crude oil (see Figure 1.9) and gas (see Figure 1.10) production in the United States, Canada, and Mexico for the three scenarios.
In the Partial Transition and NZ2050 cases, the peak oil and gas production in the United States has already been reached. In the Reference case, the peak oil production would be reached around 2030, followed by relatively flat production thereafter. Gas production follows similar trends.
The energy outlook projections in Figures 1.9 and 1.10 show a large spread between the three scenarios, reflecting the uncertainty in the future political actions by governments, availability and cost of alternative energy and green fuels, and technological advances in carbon capture, large capacity
batteries and fuel cells. Increase in the use of electric vehicles will have an impact on gasoline demand and consequently on oil demand, production and transportation; however, to achieve zero carbon life cycle for electric vehicles, alternative energy sources such as wind, hydroelectric, and solar are needed.
Hydrocarbons will continue to be a part of the energy mix, but their share is likely to decrease if the use of alternative fuels continues to increase at a faster rate than oil production increases. This will introduce a major transition to both the energy industry and consumers. New energy sources and fuels, such as biofuels, ammonia, and hydrogen, can introduce new safety and pollution concerns, and the regulators, the research community, and the industry are encouraged to proactively review and address any potential adverse effects from these transitions. While energy transition is taking place, continued attention to environmental concerns associated with fates and effects from human-caused chronic and episodic inputs of petroleum and fossil fuels remains critical.
1.2 STUDY RATIONALE
This study is the fourth in a series by the National Academies on inputs, fates, and effects of petroleum-based hydrocarbon mixtures in the sea. The first study, Petroleum in the Marine Environment, was published in 1975. As understanding of the science surrounding oil in the sea advanced, new reports were released. Table 1.1 lists the report series and sponsors.
Nearly two decades have passed since Oil in the Sea III was released. Since the last report, there have been significant advances in technology and science in general. There are almost 20 additional years of research on long-term
TABLE 1-1 Oil in the Sea Report Series
|1975||Petroleum in the Marine Environment||U.S. Environmental Protection Agency (U.S. EPA), U.S. Coast Guard (USCG), Office of Naval Research, The Rockefeller Foundation, American Chemical Society|
|1985||Oil in the Sea: Inputs, Fates, and Effects||USCG|
|2003||Oil in the Sea III: Inputs, Fates, and Effects||Mineral Management Services, U.S. Geographical Survey (USGS), USCG, U.S. Department of Energy, U.S. EPA, National Oceanic and Atmospheric Administration (NOAA), U.S. Navy, American Petroleum Institute (API), National Ocean Industries Association|
|2022||Oil in the Sea IV: Inputs, Fates, and Effects||API, Bureau of Ocean Energy Management, Bureau of Safety and Environmental Enforcement, Fisheries and Oceans Canada, Gulf of Mexico Research Initiative (GoMRI), National Academies of Sciences, Engineering, and Medicine’s Presidents’ Circle Fund|
effects of oil spills on the environment from accidents such as the Exxon Valdez. Since 2003, there have been six large (more than 10,000 bbl) spills in North American waters (see Figure 1.11), including the largest maritime spill in North American history, the Deepwater Horizon explosion and oil spill (see Box 1.1), referred to throughout this report as the DWH oil spill. Financial support for science issued directly from BP following the spill along with the civil and legal penalties, and enactment of the Natural Resource Damage Assessment (NRDA),4 led to a wealth of new research and literature on oil spill science. This surge in knowledge was a strong impetus for the committee’s undertaking of Oil in the Sea IV.
It should be noted that several other relevant studies have been conducted by the National Academies since the 2003 report to better understand inputs, fates, and effects of oil in the sea:
- Oil Spill Dispersants: Efficacy and Effects (2005)
- An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico (2013)
- Responding to Oil Spills in the U.S. Arctic Marine Environment (2014)
- Spills of Diluted Bitumen from Pipelines: A Comparative Study of Environmental Fate, Effects, and Response (2016)
- The Use of Dispersants in Marine Oil Spill Response (2020)
1.2.1 Statement of Task
The committee’s Statement of Task is included in Box 1.2. The committee’s deliberations and report writing were informed by review of scientific literature and by a series of public meetings and presentations, drawing in expertise from academic, governmental, and non-governmental organizations.
In designing the study, the committee first reached consensus on what was and was not to be included in the report by defining four key terms included in the Statement of Task:
Oil: fossil fuel hydrocarbon; organic compounds containing primarily hydrogen (H) and carbon (C); originating from natural gas and petroleum present in geological formations; in their natural forms or as their human-produced hydrocarbon-containing derivatives (refined and modified products) in different physical states (gas, liquid, solid)
Marine environment: oceans, coastal ecosystems, and estuaries
Marine life and ecosystems: organisms directly in or in contact with the marine environment, at least part of the time
4 See https://darrp.noaa.gov/what-we-do/natural-resource-damage-assessment.
North American waters: includes the countries of Canada, the continental United States and Hawai’i, and Mexico; extending seaward of these land masses to the exclusive economic zone (EEZ) established by the 1982 United Nations Convention in the Law of the Sea. In regions where the seaward boundary of the EEZ terminated before the base of the continental slope, North American waters extend to the base of the slope.
There are several important distinctions between this study and previous ones in the series. “Oil” is referred to in several ways in the Statement of Task, including as “hydrocarbons,” “fossil fuel hydrocarbons,” and “petroleum.” The committee chose to define “oil” in this report to mean “fossil fuel hydrocarbons.” Whereas the 2003 report’s definition was limited to the liquid state, this committee’s definition incorporates the gas, liquid, and solid states of fossil fuel hydrocarbons. Including the gaseous state allows the committee to consider hydrocarbon inputs into the water column such as those dissolved from natural seeps.
By opening up the definition of fossil fuel hydrocarbons to the solid state, flocculants and tar balls are also addressed. The committee also discussed possible inclusion of plastics composed of hydrocarbons synthesized from petrochemicals in the inputs section, as they are a source of fossil fuel hydrocarbons in the sea, but (1) the committee felt plastics, which
include more than hydrocarbons (e.g., cellulose acetate), were beyond the spirit of the task and (2) a National Academies report quantifying the United States’ contribution to global marine plastic waste (NASEM, 2021) was under way concurrently with the Oil in the Sea IV study and should be referenced to understand the additional volume, transport, and fate of plastic pollution in the sea.
Additionally, the committee included a chapter (Chapter 2) to further define the commonly used but complex term “oil” and to review the basic physical chemical properties of gas, oil, and gas and oil mixtures. This chapter is foundational to later discussions on fates and effects of oil in the sea in Chapters 5 and 6. Geographically, this study encompasses North American waters, which the committee defined to include waters surrounding the continental United States, Hawai’i, Canada, and Mexico. The committee used the same geographic zones as presented in Oil in the Sea III, which are also included in Appendix A of this report.
In terms of defining marine life and ecosystems, the committee determined that humans are part of the marine ecosystem and therefore examined the effects of oil in the sea on human health that had not been thoroughly evaluated in previous reports in this series. This evaluation included the potential direct effects of crude oil and of crude oil components and derivatives through inhalation, ingestion, and skin contact on response workers and community members. The committee also evaluated the growing literature on the socioeconomic impact of oil spills on the mental and behavioral health of local community members.
Fates and effects of oil in the sea are not only coupled in many ways, they are also dependent on the particular oil spill response. Each response effort, from natural attenuation to complex operations, influences the fate and effects of oil in the sea. For this reason, a chapter on source control and response is also included (see Chapter 4).
1.2.2 Progress on Oil in the Sea III Recommendations
The committee’s charge includes identifying progress made on recommendations included in the Oil in the Sea III report and, specifically, highlighting recommendations that have not been acted on, but remain a priority. Table 1.2 summarizes the committee’s opinion on the status of each recommendation in Oil in the Sea III. Many of the recommendations are not
TABLE 1-2 Recommendations from Oil in the Sea III: Inputs, Fates, and Effects
Significant progress has been achieved
Recommendation partially addressed
Recommendation not addressed
|#||Recommendation (with cross-reference to information supporting the rating, within the current report)|
|1||Federal agencies, especially the U.S. Geological Survey (USGS), the Minerals Management Service (MMS), and the National Oceanic and Atmospheric Administration (NOAA) should work to develop more accurate techniques for estimating inputs from natural seeps, especially those adjacent to sensitive habitats. (Chapter 3)|
|2||To refine estimates associated with non-point sources, federal agencies, especially the U.S. Environmental Protection Agency (U.S. EPA) and the USGS, should work with state and local authorities to routinely collect and share data on the concentration of petroleum hydrocarbons in major river outflows and harbors in storm and wastewater streams. (Chapter 3)|
|3||The comprehensive port control regime, administered by the U.S. Coast Guard (USCG), cooperative programs with ship owners and the boating community, and active participation of the International Maritime Organization (IMO) in developing effective international regulatory standards have contributed to the decline in oil spills and operational discharges. These efforts and relationships should be continued and further strengthened where appropriate. (Chapter 3)|
|4||Federal agencies, especially the USCG, should work with the transportation industry to undertake a systematic assessment of the extent of non-compliance. If the estimates of noncompliance assumed in this report are essentially correct, more rigorous monitoring and enforcement policies should be developed and implemented. (Chapter 3)|
|5||Federal agencies, especially the U.S. EPA, should continue efforts to regulate and encourage the phase-out of inefficient two-stroke engines, and a coordinated enforcement policy should be established. (Chapter 3)|
|6||The USCG should work with the IMO to assess the overall impact on air quality of VOC from tank vessels and establish design and/or operational standards on VOC emissions where appropriate. (Chapter 3)|
|7||Federal agencies, especially the Federal Aviation Administration, should work with industry to more rigorously determine the amount of fuel dumping by aircraft and to formulate appropriate actions to limit this potential threat to the marine environment. (Chapter 3)|
|8||Federal agencies, especially NOAA, MMS, the USCG, and the USGS, should work with industry to develop and support a systematic and sustained research effort to further basic understanding of the processes that govern the fate and transport of petroleum hydrocarbons released into the marine environment from a variety of sources (not just spills). (Chapter 5)|
|9||Federal agencies, especially the U.S. Coast Guard, NOAA, and U.S. EPA, should work with industry to develop a more comprehensive database of environmental information and ambient hydrocarbon levels, and should develop and implement a rapid response system to collect in situ information about spill behavior and impacts. (Chapters 5 and 6)|
|10||Federal agencies, especially the USGS, NOAA, U.S. EPA, and MMS, should develop and support targeted research into the fate and behavior of hydrocarbons released to the environment naturally through seeps or past spills. (Chapter 5)|
|11||Federal agencies, especially the USGS and U.S. EPA, should work with state and local authorities to establish or expand efforts to monitor vulnerable components of ecosystems likely to be exposed to petroleum releases. (Chapter 6)|
|12||To assess the impacts attributable to different sources including oil spills and nonpoint sources, federal agencies, especially the USGS and U.S. EPA should work with state and local authorities to undertake regular monitoring of total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) inputs from air and water (especially rivers and harbors) to determine background concentrations. (Chapter 3)|
|13||Federal agencies, especially the USGS, MMS, NOAA, and U.S. EPA, should work with industry to develop or expand research efforts to understand the cumulative effects on marine organisms. Furthermore, such research efforts should also address the fates and effects of those fractions that are known or suspected to be toxic in geographic regions where their rate of input is high. (Chapter 6)|
|14||Federal agencies, especially the USGS, U.S. EPA, and NOAA, should work with state and local authorities and industry to implement comprehensive laboratory- and field-based investigations of the impact of chronic releases of petroleum hydrocarbons. (Chapter 6)|
|15||In areas of sensitive environments or at-risk organisms, federal, state, and local entities responsible for contingency plans should develop mechanisms for higher levels of prevention, such as avoidance, improved vessel tracking systems, escort tugs, and technology for tanker safety. (Chapter 3)|
The U.S. Departments of the Interior and Commerce should identify an agency, or combination of agencies, to develop priorities for continued research on the following:
|17||The federal agencies identified above, in collaboration with similar international institutions, should develop mechanisms to facilitate the transfer of information and experience. (Chapter 6)|
written in a way in which success is measurable; in some cases the agencies called out have changed (or the agencies’ responsibilities have changed); and in many cases there is no funding source to support the recommendations. For these reasons, the committee categorized the recommendations by whether or not (1) significant work has been accomplished, (2) the recommendation has been partially addressed, or (3) the recommendation has not been acted upon.
In the committee’s assessment, significant progress has occurred toward addressing three of the recommendations. Recommendations partially addressed in the areas of fates and effects are primarily due to the surge in research following the DWH oil spill; the ranking is not necessarily indicative of specific agency or interagency response. Most notably, significant progress was made on recommendations aimed at reducing oil inputs into the sea (Recommendations 3, 5, and 6)—the committee commends these efforts. Recommendations 1, 2, 4, 7, and 12, which were aimed at better quantification of oil inputs into the sea were largely not addressed. Recommendation 8 regarding sustained funding and effort to advance understanding of fates, and Recommendations 14 and 16, regarding the effects of oil in the sea were not addressed outside the context of the DWH-funded research. Details on recommendations that have not been fully addressed but remain a priority are called out in the appropriate sections within the body of this report.
Throughout the study process, the committee acknowledged the remarkable and unprecedented advancements seen in oil spill science in the past 20 years, especially following the DWH oil spill.5 Research funding sustained for over a decade was a key factor leading to the wealth of knowledge described in this report. This is not to say that unrelated efforts have not also been impactful, but it is clear what can be done with a continued dedicated funding stream, as seen over the past decade and as called for in previous Oil in the Sea recommendations.
This report aims to augment, but not repeat the information provided in Oil in the Sea III. During the writing of this report, more published information became available and will become available after this compilation is completed. The committee has aimed to bring the most recent published research to light.
Reiterating past recommendations, and to keep the momentum expanding understanding of the fates and effects of oil in the sea in the context of a constantly evolving fossil fuel landscape (i.e., changes in exploration, production, transportation, consumption of oil as well as the chemical composition of oil being transported and consumed), and to reduce and mitigate oil’s impact on the marine environment, the committee developed the following overarching conclusion and recommendation, which is echoed throughout the report.
Conclusion: Long-Term Funding Enables Great Advances in Knowledge
The establishment of, and 10 years of funding for, the GoMRI after the DWH oil spill resulted in an extraordinary output of discipline-specific research and, more importantly, of multidisciplinary research by funding a mix of field, laboratory, mesocosm, and test facility research, and related modeling. Similar periods of advancement were seen following other oil spills such as the Exxon Valdez and the Hebei Spirit. Advancement of oil spill science has a history of being hindered by a boom and bust funding cycle, which led to the inability to sustain continuity of oil spill research along with the scientific community conducting that research.
1.2.3 Report Organization
The Statement of Task aligns with the narrative of how oil interacts with the sea, and this is how the report is organized, shown in Figure 1.12. Chapter 2 sets the stage by delving into
5 There are thousands of scientific publications and reports pertinent to the committee’s task; where practicable recent published reviews and a selection of relevant specific references were cited—it was impractical to cite all papers in the report’s subject areas published since 2003.
the details of exactly what oil is, incorporating important advancements in analytical chemistry and models to predict oil behavior. The journey begins in Chapter 3 with the origin of oil that ends up in the sea. Where is the oil coming from? What are the quantities of oil input into the sea? How have the quantities changed since Oil in the Sea III? How do we expect the volumes to change into the future and what other forms of potential inputs might be realized in the coming years? What can be done to prevent oil from entering the sea? Chapter 4 then discusses accidental spill mitigation measures through both source control and response in terms of what can be done to reduce the quantities of oil entering the environment and also to minimize the negative effects of oil on the marine ecosystem. Chapter 5 continues the story of what happens to the oil once it reaches the sea, assimilating significant advancements in understanding of transport and fate of oil in the sea. The story ends with Chapter 6, which discusses the harm the oil can have on the marine environment and marine organisms over its journey from source to contact, synthesizing a vast amount of literature focused on effects of oil on both the ecosystem and on humans.
Within each subsequent chapter, findings are identified in bold text. Synthesis of those findings is included in the last subsection of each chapter, described through conclusions and a list of specific research needs to advance understanding of the particular subject.
Although the committee has divided the report into distinct chapters, complex and intrinsic interdependencies exist among inputs, fates, effects, and the measures to reduce them—either from the source or by response. Because of the interconnected nature of oil spill science, overall recommendations are not specifically tied to one topic (or chapter) or another and are therefore presented in the final chapter of this report (see Chapter 7).
The Venn diagram in Figure 1.13 depicts the complicated relationships among oil parameters, environmental conditions, and biological components. These interactions illustrate the multitude of parameters adding to the complexity of changes over time and space in determining the potential effects from an oil spill and appropriate response strategies. While the listing of items in the diagram is not exhaustive, it clearly depicts the numerous combinations of possible variables. Thus, this simple diagram helps to serve as a visualization of the aspects covered in each of the chapters in this report.