As the impacts of climate change become more apparent, a portfolio approach that includes carbon capture and storage can serve as a scalable, systems-level climate solution. The system governing carbon concentration in the atmosphere is unsustainable, due to the imbalance of greater inflow of anthropogenic emissions compared to the outflow of natural dissipation and continued global reliance on fossil fuel and natural gas combustion to meet energy demand (Carter 2021). There are a variety of natural and technological carbon capture and sequestration (CCS) strategies available today, and technological solutions like capturing carbon dioxide (CO₂) emissions from industrial hotspots can allow for iterative modernization of the energy infrastructure over a realistic period of time. This strategy can act as a bridge between needs of the past and future, and realistically address base load energy demand and source reduction. This research presents a system analysis of the concentration of carbon in the atmosphere and provides recommendations on ways to manage the inflow and outflow within the system using CCS technologies, including point source capture and capture of carbon previously admitted.

Authors:

Background: Alyssa Harding

Environmental Impact Analyst: Nicole Manesh

Systems Analyst: Luke Vail

Sustainability Analyst: Logan Callen

Conclusion: Erik Anderson

for Master of Science, Environmental Policy and Management

University of Denver

Faculty: Jay Cooper Beeks, Ph.D.

Presentation

Background

Carbon capture and storage is not a new technology; companies have been extracting carbon dioxide (CO₂) from industrial processing since the 1930’s (Carter 2021). Today the impacts of climate change are reaching an alarming level, making it necessary to use a portfolio approach to meet energy consumption levels and reduce carbon dioxide (CO₂) emissions. Carbon capture and storage can help bridge the gap in the energy portfolio approach and can be easily implemented to offset the current climate crisis. Carbon capture and storage has the capability to remove carbon dioxide (CO₂) emissions from fossil fuel-based energy power plants and increase clean energy technologies in the United States.

Today, fossil fuels and natural gas are the leading sources of energy in the United States (EIA 2020b). The Driving Force for the system is the continuously increasing human demand for reliable and affordable energy. Indicators for the Driving Force can be found in Appendix A below, including 2018 data that shows a growth in the consumption of both natural gas (at 3,928 billion cubic meters), and total electricity (at 22,315 TWh) from previous year’s baselines. The increasing human demand for energy forces Pressure on the system because the majority of energy sources being exploited today in the United States releases carbon dioxide (CO₂) emissions and additional toxic greenhouse gases into the atmosphere, disrupting naturally occurring systems. 

Environmental Impact Analysis

Carbon capture and storage holds the potential to reduce the total worldwide carbon dioxide (CO₂) emissions by up to 10 gigatons of carbon dioxide per year (National Academies of Sciences Engineering. 2018). The current carbon emissions produced in the United States from the combustion of fossil fuels is not sustainable. According to NOAA (2020b), cuts of around 0.3 to 0.6 Gt carbon dioxide emissions (or 1 to 2 Gt of CO₂) are going to be necessary every year between 2020 and 2030 to limit climate change in line with the current goals outlined in the Paris Agreement. In 2020 alone, the average annual concentrations of carbon dioxide (CO₂) in the atmosphere were 412.5 parts per million (IEA 2021a). Applying and expanding carbon capture and storage at fossil fuel-based energy sites in the United States would lessen the overall amount of carbon dioxide (CO₂) emissions and other greenhouse gases from the atmosphere (DOE 2020).

Impact on the Spheres

The environmental impacts from carbon dioxide (CO₂) emissions associated with energy production to meet consumption levels in the United States are disrupting the natural system within the Earth’s spheres (see Figure 1 below). These emissions have polluted the atmosphere and increased ocean acidification in the hydrosphere, and in the lithosphere, heat is being absorbed and leading to desertification (Lindsey 2021). Additionally, the health of all species, including human health threatens the biosphere with increased mortality rates, desertification, and land degradation (Burrows 2021). According to Burrows (2021), air pollution from fossil fuel-based energy plants is responsible for negatively impacting human health for more than 8 million people. As of 2019, carbon dioxide- based emissions from climate change are currently affecting 19% of species listed as “threatened”, increasing their likelihood of extinction (IUCN 2019). Since the carbon capture and storage process traps emissions from heavy industrial power generation processes in facilities, it effectively reduces emissions impact on the atmosphere, hydrosphere, lithosphere, and biosphere and can serve as a bridge during the transitional period to cleaner energy sources.

Humans and Property

 Storing carbon and capturing it from the atmosphere would be to the benefit of human health, as well as developing the economics associated with carbon dioxide (Tan et al. 2016). Carbon capture and storage technology is being utilized internationally in Sweden and France to heat homes and other properties and is being viewed as a carbon-free energy source to lower global carbon dioxide emissions (Tan et al. 2016). Property concerns and heat capacity were raised originally by homeowners, including home values, safety of being in close proximity to carbon storage facilities, and overall community character for these neighborhoods. If the correct balance and public access and education to information about carbon capture and storage technology was struck during the time of its initial development for homes and properties, society would have a more adaptive and accepting perspective on carbon capture and storage potential (Tan et al. 2016).

Carbon Capture and Storage Concerns

Carbon capture and storage technologies are not without environmental flaws. Critics assert that carbon capture and storage pose potentially negative environmental impacts contributing to the depletion of natural resources (Singh et al. 2015). Further energy supply will be necessary for capturing the carbon dioxide-based emissions and will most likely utilize more fossil fuel resources during the transportation of these carbon (CO₂) emissions to be stored (Singh et al. 2015). One of the most significant concerns is that the carbon capture and storage process will not offset more greenhouse gases and carbon dioxide emissions than it is able to prevent from disrupting the atmosphere. Due to the current human application of the carbon capture and storage mechanical process, efficiency concerns are present. Additionally, the storage containers required for carbon capture storage technology will also contribute to depletion of metal (Singh et al. 2015).  The necessary production increase for metal containers will be required to store the captured carbon properly and safely. It is estimated that for every ton of steel that is produced for metal production that 1.85 tons of carbon dioxide is emitted, worsening the total global carbon dioxide emissions significantly (EPA 2021). The environmental concerns associated with carbon capture and storage are present, but with emerging advances in clean and renewable energies many of these qualms have the potential to be offset or lessened as technology advances.

Environmental Benefits

The benefits that carbon capture and storage (CCS) can contribute to human health and ecosystems from reduced climate change related impacts considerably outweigh any negative impacts from using the emerging technology in power plants. The excess of carbon dioxide-based emissions from the current unstable energy system is hurting the environment substantially. Human health risks, species survival and habitat loss, and ocean acidification is continuing to escalate due to the excess of carbon dioxide emissions (Singh et al. 2015). These environmental crises along with the currently degrading atmosphere, biosphere, hydrosphere, and lithosphere conditions can all benefit significantly from the removal or storage of carbon dioxide emissions through carbon capture and storage technologies (see Figure 1 below).

Managing to capture and safely dispose of carbon emissions from power plants will help contribute to the evolving clean and renewable energy transition occurring in the United States and internationally. Switching from current fossil fuel powered technologies to electric vehicle-based technologies, carbon capture and storage can be utilized during this transitional period as a parallel path approach to systems emission reductions. Currently the United States Department of Energy is working with private industries to further develop carbon capture technologies to make them more sustainable, and this research suggests that CCS can serve as a bridge to a cleaner energy economy as moratoriums on fossil fuel and carbon intensive energy production phase in (DOE 2020). The Department of Energy (2020) is working and researching over 18 projects that will be “Direct Capture of Carbon Dioxide from the Atmosphere”. The selected projects will help the United States create technical solutions needed to help reduce carbon (CO₂) emissions balancing the nation’s energy consumptions while continuing to work towards overall energy-based emission reductions and help the health of earth’s natural systems (DOE 2020). 

System Description

Meadows

The Source in this system is the energy demand required by humans to satisfy everyday needs and behaviors. Nearly 84 percent of the energy consumed by humans to satisfy these needs and behaviors is produced using fossil fuels, the combustion of which emits CO₂ into the atmosphere (IEA 2020c). The constant flow of fossil fuel combustion for energy production into the system continually increases atmospheric CO₂ concentrations. This increased concentration of atmospheric CO₂ represents the stock in this system. As of 2020, the concentration of CO2 in the atmosphere has reached a record high of 412.5 parts per million (ppm) (IEA 2021a). According to Rahman et al. (2017, 112) the acceptable threshold for atmospheric CO2 concentration is only around 350ppm which is clearly exceeded by the current concentration.

There are natural sinks in this system such as photosynthetic plants, and oceans whose natural processes remove carbon from the atmosphere (McKinney et al. 2019, 491). However, these natural sinks cannot keep up with the amount of carbon that is released from anthropogenic sources. This means the system’s inflows far outweigh the outflows, resulting in a surplus of the stock (atmospheric CO₂). Increased atmospheric CO₂ concentrations lead to climate change impacts including changing weather patterns, drought, ocean acidification and desertification (among other impacts on the spheres) that require additional energy production and consumption to be addressed (McKinney et al. 2019, 481-84). This produces a destructive feedback loop in which the impacts of the system’s stock increase the demand for harmful flows into the system due to the unbalanced nature of the system’s flows.

Therefore, CCS technologies have the potential to be leveraged as an additional sink in this system to bridge current energy usage to a green energy future. CCS technologies are capable of both reducing the amount of CO₂ that is emitted during combustion and reducing the inflow of CO₂ into the stock, but also remediating CO₂ that is already in the atmosphere, creating an additional outflow to the system. The CO₂ sequestered by CCS technologies can then be removed from the system through several methods such as underground storage, being used as energy feedstocks or to produce building and industrial materials (Roberts 2019). This alternative to the existing system would in turn alleviate the effects of the destructive feedback loops that arise in response to global energy demand. Both the current and alternative systems are illustrated by systems diagrams in Figure 2 below.

DPSIR Analysis

The driving force of this system is the need for reliable, accessible, and affordable energy to satisfy human needs and behaviors. Currently, this energy use is supported by the use of electricity, natural gas, and liquid fuels, the current consumption of which is outlined in Figure 1 above. The pressure on the system comes from the fact that many of these energy sources release CO₂ and other greenhouse gases such as methane and nitrogen oxides into the atmosphere. This includes coal used for electricity production and natural gas. These CO₂ emissions then accumulate in the atmosphere and hydrosphere, and the extraction of oil and gas depletes reserves in the lithosphere, altering the state of the system. The impacts of these changes to the system are felt in the form of heat trapped within the atmosphere, ocean acidification, desertification and other natural hazards, and increased mortality rates among several species. Responses to this issue need to come in the form of policies that promote a transition to renewable and low-carbon forms of energy production while emphasizing CCS as a bridge technology for renewable penetration. Ideally, a response would require CCS for any source releasing carbon through combustion, coupled with policies that protect forests and other natural carbon sinks, implement a social cost of carbon, and incentivize the use of renewable energy. The full scope of this system and its environmental impacts are illustrated in Figure 3 below.

Sustainability Analysis

The global demand for reliable and affordable energy has led to an energy system that generates large amounts of carbon dioxide. This energy system is currently unsustainable as it creates greater emissions than can be dissipated naturally. The carbon dioxide released to the atmosphere creates detrimental impacts to the environment, economy, and society. From this triple-bottom line perspective, the energy system is currently unsustainable and will require actions to avoid additional damages. Carbon capture and sequestration (CCS) technology will play a critical role in the decarbonization of the energy system (IEA 2020e).

Environmental Sustainability

Major impacts from excess carbon dioxide from this unbalanced energy system can be seen in the environment. Carbon emitted to the atmosphere has led to the average annual concentration of carbon dioxide in the atmosphere to be 412.5 parts per million (IEA 2021a). It is expected that this will increase to between 730 and 1,020 ppm by 2100. These increases are expected to lead to temperatures likely landing in the 2-4.5°C range above pre-industrial levels. The hydrosphere also absorbs a lot of the excess atmospheric carbon that leads to greater ocean acidification, continuing from the current 0.1 pH unit decrease from pre-industrial times and moving down another 0.14-0.35 pH units (IPCC 2018b, 749-750). Currently, 19% of species listed as “threatened” are affected by climate change, increasing the likelihood of more extinctions of species in the biosphere (IUCRN 2019). Continued emissions of carbon dioxide for energy demand will continue to upset all the different environmental spheres. CCS technology is expected to contribute 15-55% of the cumulative mitigation efforts worldwide through 2100 if implementation is adopted (IPCC 2018a, 12).

Economic Sustainability

These environmental impacts not only create issues to the environment, but they lead to economic losses as well. In 2020, climate related disasters were estimated to have caused $210 billion in damages (Newburger n.d.). Additionally, in the U.S. alone, climate change is estimated to have impacted crops, livestock, and fisheries in the billions of dollars per year as well (EPA 2017). To fully implement the research and development, storage, and use of CCS, it is estimated that $15 billion would be needed in the next 10 years (NPC 2019, 34). The scaling up of this technology also allows bioenergy with CCS (BECCS) to be utilized and would represent negative emission approaches that will be critical moving forward (NPC 2019, 12). The cost of inaction in reducing carbon dioxide emissions greatly exceeds the costs of implementing CCS to help decarbonize and enable transitions to cleaner renewable energy.

With the Biden administration raising the social cost of carbon to around $51 per ton, CCS technologies help transition to clean energy resources while providing cost effective solutions to removing carbon from current energy and industrial plants, as well as industries like cement, steel, and chemical manufacturing where there are limited other options (Chemnick 2021). Carbon capture costs vary widely between different projects but can range from $15-25/t CO₂ for concentrated sources like natural gas or hydrogen processing, or things like bioethanol and ammonia. For more dilute streams like cement and power production, the costs can range higher in the $40-120/t CO₂ (IEA 2021g). Many of these technologies are already below that social cost of carbon. There are other biological sequestration methods that will be useful as well, like forests and algae farms, however those methods do not provide the solutions for other industries like CCS at source points can offer. CCS helps keep dispatchable baseload energy available to support the increase of intermittent non-dispatchable renewable resources at the lowest cost (NPC 2019, 8). For these economics to be implemented to their maximum potential, policy and other legal frameworks will need to be implemented in addition to management of environmental impacts and risks (IPCC 2018a, 12).

Social Sustainability

Decarbonization of the global energy system is not only critical to reducing environmental and economic destruction, it also will reduce the loss of human life. It is estimated that fossil fuel-based air pollution is responsible for nearly 8 million human deaths globally (Burrows 2021). Additionally, climate change impacts from carbon emissions create equity, poverty, and quality of life issues as well. Common resources, like the atmosphere, are currently being exploited by fossil fuel corporations that can externalize their costs to everyone across the globe. With an estimated cost of carbon of $51 per ton, and 50 gigatons emitted per year, that comes to approximately $2.5 trillion dollars that is externalized to the public globally. This tragedy of the commons system trap leads to developing countries not only being saddled with the burden of climate change and sea-level rise and their corresponding costs to mitigate the issues, but it also creates an unfair advantage to those countries already profiting from the pollution, leading to a success to the successful system trap as well (Meadows 2008, 116-130).

Additionally, the social inertia present in the fossil fuel economy should not be ignored. With the fossil fuel industry representing approximately $18 trillion dollars of market capitalization in the economy, policies that do not provide them flexible solutions are likely unable to pass the political process due to lobbying and corporate influences on government in addition to the wasted effort to enforce a large resistant sector (Scott 2020). With investment banks also loaning nearly $750 billion to fossil fuel companies as well, it is important to ensure those actors are included in collaborative policies to avoid resistance traps (Nauman and Morris 2021). A flexible policy, like a carbon tax, can not only incentive companies to move towards the important goal of carbon emission reductions, but it also enables market efficiencies and collaboration to allow those businesses to focus on finding methods, like CCS, to decarbonize that allow them to transition without major disruptions to their businesses. The energy system’s unnecessary generation of carbon dioxide creates large-scale issues to the environment, economy, and society and removing those emissions should be the primary goal of collective social actions. This currently unsustainable energy system will require various coordinated urgent actions, like enabling adoption of CCS, to counteract the system’s current inertia towards catastrophic issues.

Analysis

This section will contain a brief analysis on the suitability of CCS technology in a climate change mitigation strategy and to what extent it should be implemented amid competing contributors to a clean energy economy. These factors will be viewed through the lens of cost-effectiveness, overall impact, and long-term sustainability.

Recommendations

Recommendations are based on the technical, scalable, cost-effective, feasible, and impactful nature of CCS technology in a climate change mitigation strategy.

Basis of Recommendations

The results of the environmental impact analysis, sustainability analysis, and system analysis all contribute to the conclusion that CCS technology is a high-value component of a climate change mitigation strategy and will likely be instrumental in bridging the gap between fossil fuel dependency and a clean energy economy. This finding is supported by several studies recently undertaken and published by reputable research organizations. For instance, the United Nations Economic Commission for Europe stated in a technical analysis that “Carbon capture, use, and storage (CCUS) technology is an essential step towards mitigating climate change…”, “CCUS technologies are the key to unlock the full decarbonization of the energy sector…”, and “CCUS may be expensive, but it is an affordable option for an economy that aspires to be carbon neutral” (UNECE 2021). Furthermore, another study concluded that CCUS technology is low-risk and well-entrenched from a technical standpoint, beneficial to the environment as it incorporates a system perspective to mitigate technosphere impacts and creates an open-loop recycling of CO2–carbon, and economically viable for scaling when compared to other sequestration services given a price point for carbon and use-infrastructure (Mikhelkis and Govindarajan 2020).

A significant contributor and point of reference for the optimism described in CCS feasibility studies is the current and projected state of the system as it relates to concentration of carbon dioxide in the atmosphere. In 2020, carbon dioxide concentration in the atmosphere reached 412.5 million parts per million (Tieso 2021), and with inflows consistently overwhelming ecosystem services’ ability to outflow carbon dioxide through natural dissipation and sequestration, the timeframe for atmosphere recovery is pushed back exponentially; at 2010 levels, it would take ~900 years for carbon dioxide to dissipate to preindustrial levels given no additional emissions (Mearns 2014). Despite the rapid adoption rate of electricity as a fuel over the past decade and the associated growth rates of natural gas and renewables (40% and 21% of total generation, respectively (EIA 2021b), research organizations like the International Energy Agency (IEA) remain skeptical of encompassing net-zero greenhouse gas emission commitments made by developed countries (IEA 2019), being fueled by reports like those published by the U.S. Energy Information Administration that project renewables will only make up 42% of electricity generation by 2050 (EIA 2021b) and from McKinsey & Co., that find coal, oil, and, gas will continue to be 74 percent of primary global energy demand in 2050 (Nyquist 2016). These findings tend to coincide with the projected industrialization period of emerging markets and developing countries, and the continued exportation of externalities and polluting industry by developed ones. In any sense, there seems to be a growing consensus that CCS is a critical part of the future industrial technology portfolio and evolving climate mitigation strategy, especially as demonstration projects provide high efficiency rates; CCUS is expected to deliver almost one-fifth of the emissions reductions needed across the industry sector (38% emissions reductions in chemical subsector and 15% in both cement and iron and steel subsector) (IEA 2019) and 15% of the cumulative reduction in emissions in the energy sector by 2070 (IEA 2021). Furthermore, in the oil sands industry, direct-use CCUS can mitigate 7% of industry GHG emissions from 2020 to 2050 at -$16.15/tCO2e (Janzen, Davis, and Kumar 2020).

Personal, Corporate, and Policy Recommendations

Although CCS has been deployed most extensively in the US, it remains an emerging technology nationally and globally. Therefore, personal and corporate level actions are likely to be of a lesser scale than that of potential policy actions, which will be the main driver of future CCS use as a climate mitigation tool.

Personal Recommendations

Though it may appear the future of CCS is out of the average person’s control, this is not entirely true. Those that support increased public spending on climate change mitigation plans, environmental protection, energy reform, ambient quality (air), and responsible long-term economics have the right to advocate, vote, assemble, protest, hold office, and influence political representatives in a way that favors CCS scaling and implementation. Although individuals likely will not affect the adoption rate of CCS through their own spending power, personal shifts to less energy and resource intensive activities will contribute to the overarching goal that CCS is a component of – reducing the concentration of carbon dioxide in the atmosphere and inhibiting the continued devastation of global climate change. Other ways individuals can become involved in the shift to CCS is investing in private or public companies that have stakes in CCS deployment or ESG initiatives or championing a movement at one’s own company to become a more responsible asset holder.

Lastly, individuals who wish to contribute to the scaling and implementation of CCS can help make others more aware and competent of associated costs and benefits, technical information, and legal proceedings. This recommendation targets Leverage Point 6, “Information Flows – the structure of who does and does not have access to information”, described in Thinking in Systems, A Primer (Meadows 2008) as improving the pathways that distribute the spread of factual, system-based information. This is process is cornerstone to rallying the support of communities, from local to international and at all levels of the socioeconomic pyramid, in efforts against climate change. Information flows contribute to the revision of Stock-and-Flow Structures (Leverage Point 10) and the evolution of worldviews and transcendence of paradigms (Leverage Point 2), both of which are necessary for the advancement of environmental stewardship (Meadows 2008, 139). In this way, CCS could be more of a consumer-end demand, or a grassroots push, than a top-down strategic necessity or pull (at least without policy intervention). 

Corporate Recommendations

Corporate actions also have their limitations, as the technical aspects of CCS have largely been scoped and executed on in demonstration projects; the next step is to establish a tangible measure of value for CCS services, which a market devoid of concrete considerations for ecosystem services is unlikely to produce on its own, even with increasing stringency of standards. As previously noted, corporations can be driven to make more sustainable investments, such as those that have a higher risk tolerance for early-stage technologies like CCS. Corporations can also lobby in government for more stringent environmental protection standards and be more transparent and honest when sharing operational data (especially those concerning actual valuation). Arguably, industries that rely heavily on the byproducts of fossil fuels, such as the coal, oil, and gas industry, as well as the plastics, pharmaceutical, and food industry, should be some of the greatest advocates for CCS; CCS enables, to an extent, the preservation of fossil fuels as a means of power production in the future – which is becoming increasingly clouded by net-zero emissions commitments.  

Policy Recommendations

There are several ways to incentivize greater business investments in CCS technology, most of which stem from providing a monetary value for the prevention or removal of carbon dioxide from the atmosphere, either through direct-use/point-source capture or sequestration, respectively. Representatives advocating for CCS should encourage and contribute to the development of policy that effectively mandates and enforces a standard carbon pricing model, like a carbon tax. More so, a much more stringent emissions standard or cap-and-trade program would bring the allowance ceiling down to the point that the price of CCS technologies would be cost-effective with noncompliance costs and/or alternative means of reducing emissions (such as infrastructure remodeling or abandonment of hydrocarbon-based business models altogether). This recommendation is based on the Leverage Point of Numbers and the Leverage Point of Rules, which together incentivize, punish, and constrain actions that exist outside the constants and parameters set as the basis of systems goals (Meadows 2008). The use of subsidies, taxes, and standards ensures, to a quantifiable point, the protection of some standing stock of natural resources; essentially controlling system behavior like inflows and outflows through the manipulation of value, like money. Another way to use these leverage points favorably is to implement tax credits for fossil-fuel based energy power plants and industrial facilities that emits large amounts of carbon dioxide. These tax credits could be applicable in federal law (as federal tax credits) under Section 45Q of the Internal Revenue Code, as well as in state law – especially in those states that are occupied most heavily by these facilities like California, Texas, and Louisiana.

Another recommended policy that would help implement CCS would be Extended Product Responsibility (EPR), which makes producers of goods and services accountable for the byproducts and physical waste of their services. This would incentivize use cases for CCS, as carbon dioxide emitters would be tied to the gaseous byproduct of hydrocarbon combustion. The captured carbon dioxide would have a variety of uses and can be thought of as a source rather than the measure of stock in a sink. For instance, the carbon dioxide yielded from CCS operations may be used as a source in building and industrial materials, thereby offsetting a larger proportion of externalities projected by fossil fuels throughout the product life cycle.

Lastly, it is recommended that legislatures make use of Meadows’ 9th Leverage Point, which is Delays – specifically in the stock of atmospheric emissions. Even after a transition away from fossil fuels occurs, there will still be renewable biomass and biogas that is generated from solid and liquid waste streams. Developing regulations that ensure those resources require CCS technology should be implemented. Meadows (2008, 152) shows that delays in a system can act as leverage points. The requirements for CCS to be implemented on all emitting resources not only can mitigate the continued use of fossil fuels, but it will also slow down emissions to allow for more time for technology and prices to allow for more transitions to renewable energy resources while ensuring emitting renewable resources mitigated in the future as those technologies are built out more to reduce the waste stream’s pollution. Additionally, regulations that require siting of CCS storage should be limited to sites or technologies with little to no leakage. Meadows (2008, 151) showcases the fact that utilizing delays is critical for slow to respond systems. Utilizing locations or technologies that have little or no leakage risk means the emissions can be delayed from making their way to the atmosphere for longer periods of time if the locations have little to no leakage. This ensures that the emissions do not loop back into the atmosphere and can be sequestered in the lithosphere for long periods of time.

Conclusion

As the projected impacts of climate change continue to mount, it becomes more and more pressing that we develop a realistic mitigation strategy in a timely manner. In comparison to a business-as-usual scenario, strategies that reduce greenhouse gas emissions and influences from the technosphere will always be more difficult and expensive to implement, however they are likely necessary and cost-effective given the valuation of ecosystem services, discounting, and consideration for future generations. CCS has been shown to be an essential element in the bridging of the current fossil fuel dependent economy and the future clean energy economy due to its ability to retain and aid in the phasing out of existing energy and industrial infrastructure, all the while mitigating significant accumulations of carbon dioxide in the atmosphere. However, CCS also raises concerns that are intrinsic to a scaled model, the most pressing being the feasibility of bipartisan policies incentivizing use cases, unknown environmental impacts, perverse incentives that lessen the desire to wean off and eventually be fully removed from fossil fuels, and competition of resources and funding (is CCS as competitive as other mitigation alternatives?). More research needs to be conducted on CCS to answer these questions, and demonstration projects that integrate “Use” should become more prolific to show potential investors the system-end benefits of the technology. In the event direct-source CCS becomes a less strategic option for managing inflow of carbon emissions into the stock (perhaps renewables have scaled beyond expectations), CCS can be utilized as a remediation tool to open up new outflow pathways to heal the atmosphere faster than natural dissipation. Furthermore, CCS can be used as a component of more carbon-intensive renewable fuel sources, like biomass and biogas.

In the current model, CCS (along with other revolutionary technologies) faces political and economic opposition due to a lack of policy designed to incorporate the cost of ecosystem services and intrinsic value of the environment. Only once the foundation of thought is changed will communities be able to support a more meaningful and inclusive structure of human-world interactions. For the system to change, its drivers must do so first.

Appendix A – DPSIR model contents for each of the system elements along with key indicators

Nature of the Driving Force	Indicator of the Driving Force
Humans require affordable, reliable, and accessible energy to support their needs and behaviors	In 2018, global total electricity consumption reached 22,315 terawatt hours (IEA 2020c)
	In 2018, global natural gas consumption reached 3,928 billion cubic meters (IEA 2020d)
	In 2019, global liquid fuels consumption reached 100 million barrels per day (EIA 2021)
Nature of the Pressure	Indicators of the Pressure
Many sources of energy release carbon dioxide into the atmosphere like coal, natural gas, and petroleum, but also renewable resources like biomass and biogas	In 2018, global coal emissions totaled 14,766 metric tons of CO₂ (IEA 2021b)
	In 2018, global oil emissions totaled 11,415 metric tons of CO₂ (IEA 2021b)
	In 2018, global natural gas emissions totaled 7,104 metric tons of CO₂ (IEA 2021b)
Nature of the State	Indicators of the State
The release of carbon dioxide from fossil fuel resources, and even renewable resources like biomass and biogas, accumulates in the Earth’s atmosphere and hydrosphere	In 2020, average annual concentrations of CO₂ in the atmosphere were 412.5 part per million (IEA 2021a)
	In 2018, the average pH of the ocean was 8.1 (NOAA 2020)
	In 2016, there were 1.65 trillion barrels of proven oil reserves in the lithosphere (Worldometer 2021)
Nature of the Impacts	Indicators of the Impacts
The increased concentrations of carbon dioxide in the ocean and atmospheres creates more heat trapped and more acidic waters which leads to increased mortality rates, drought, famine, disease and pest oubreaks, wildfires, and desertification	In 2020, global surface temperatures were 1.0 degrees Celsius above the long-term average (Lindsey and Dahlman 2021)
	In 2018, fossil fuel air pollution is estimated to be responsible for more than 8 million humans globally (Burrows 2021)
	As of 2019, climate change is currently affecting 19% of species listed as “threatened”, increasing likelihood of extinctions (IUCN 2019)
Nature of the Responses	Indicators of the Responses
Implement regulations that require carbon capture utilization and sequestration (CCUS) for any source releasing carbon through combustion	Measure of how many metric tons of carbon are sequestered annually
Implement a global social cost of carbon for any emissions released to disincentivize carbon pollution and incentivize renewable technologies	Measure the amount of carbon tax dollars collected that are applied to carbon reduction efforts
CCUS as a bridge for baseload energy solutions as renewable penetration is increased and to enable more time for newer technologies to be developed	Measure of energy resource mix percentage changes as energy sources moves towards 100% renewable

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