6

Decarbonization

The largest contributor to greenhouse gas emissions through human activity is carbon dioxide (IPCC, 2022). Meeting the Paris Climate Agreement targets requires action throughout society, including the segments discussed throughout this report—food systems, transportation, energy usage, and more. Profound and exponential changes in human lifestyles, social institutions, governance, infrastructure, and technology are needed to meet the goals of the Paris Climate Agreement. Otto et al. (2020) propose key interventions to reduce greenhouse gases in this decade: “removing fossil-fuel subsidies and incentivizing decentralized energy generation, building carbon-neutral cities, divesting from assets linked to fossil fuels, revealing the moral implications of fossil fuels, strengthening climate education and engagement, and disclosing greenhouse gas emissions information” (Otto et al., 2020). In addition, the Intergovernmental Panel on Climate Change’s Sixth Assessment (AR6) has identified the need to permanently sequester about 10 percent of current carbon emissions by 2050 to stay within the Paris temperature limits: that is, the sequestration of 6–10 gigatons/year by 2030 or sooner.

Carbon dioxide removal (CDR) technologies capture carbon either directly from the air or at a fossil-fuel source, then reuse or sequester it depending on the method. Both engineered and nature-based methods are at different stages of research, development, and deployment: direct air capture; mineralization; soils; forests; hybrid, such as bioenergy with carbon capture (BECCS); and ocean sequestration (Table 6-1).

TABLE 6-1 Pathways for Carbon Removal

SOURCE: Erin Burns, Workshop Presentation, May 16, 2022.

CHALLENGES

Decarbonization of energy systems is central to global decarbonization and achievement of all SDGs (IPCC, 2022; Nakicenovic, 2022; Nakicenovic and Lund, 2021). A fundamental energy-systems transformation would help to address health, climate, and other challenges facing humanity, and would especially benefit individuals without access to affordable and clean energy services (GCSA, 2021; IPCC, 2022; TWI2050, 2020).

The actions needed have been assessed multiple times over the past decades (GCSA, 2021; GEA, 2012; Häfele et al., 1981; IPCC, 2018; SAPEA, 2021). The first priority is to invest in decarbonization and efficiency because worldwide investments in renewables previously peaked in 2017 and have now reached new record highs because new renewables such as wind and photovoltaics can be less expensive than fossil alternatives (REN21, 2022). In fact, the investment costs of photovoltaic cells have declined by three orders of magnitude and are now lower than $1/Watt peak (GEA, 2012; SAPEA, 2021). A pervasive transformation toward zero-carbon electricity and electrification of end uses is central to decarbonization and net-zero emissions (IPCC, 2018). This effort should be complemented by low- and zero-carbon fuels such as hydrogen and CDR, along with sustainable biomass (BECCS) to achieve net-negative emissions. Major challenges to transforming energy systems include mobility that can be electrified through electric and plug-in vehicles, heating and cooling through heat pumps, and especially freight transport, aviation, and shipping. Blue hydrogen with CDR natural gas, and then green hydrogen and decarbonized synthetic fuels, offer a viable solution (GCSA, 2021; Nakicenovic, 2022).

Even the strongest advocates warn that CDR, no matter how robust and fully deployed, can never replace aggressive carbon reduction strategies and cannot be perceived as an alternative to mitigation (Burns, 2022). Moreover, CDR technologies are in the early stages of development, their unintended consequences are not known, and they require massive scale-up and financial investment to meet the AR6 goal.

Uncertainty related to performance, longevity, safety, and trust must be addressed. Developing laws and policies that account for timescale for long-term

sequestration—up to millennia—is a similarly daunting challenge. Issues related to land-use; land ownership; and monitoring, reporting, and verification (MRV) must be resolved. The potential implications for biodiversity and society—especially given the uncertainties and the long timescale—remain unclear and the necessary data to inform decision-making are lacking. Sequestration does not create a “product,” but rather a public good that requires public investment (Burns, 2022).

CASE STUDIES AND SYNERGIES

Decarbonization is both a technological challenge and a strategy with economic, environmental, and social consequences that are both known and unknown. Investment in research, development, demonstration, and deployment across the pathways summarized above (Table 6-1) has increased. A notable example is the $1 billion investment by the U.S. government to develop four regional Direct Air Capture hubs (DOE, 2022).

Researchers in academia, the nonprofit sector, and government are addressing the myriad of technical and nontechnical issues. For example, the committee discussed decarbonization options with representatives from Carbon180 (see Box 6-1), Carbon Clean (Bumb, 2022), and the International Biochar Initiative. As noted in Chapter 2, biochar offers potential benefits for soil and agriculture that warrant further investigation (Draper, 2022). Even though large-scale public investment is required to achieve decarbonization goals, the private sector is offering solutions, such as modular carbon capture and utilization technologies (Bumb, 2022), that open up new avenues of financing for CDR.

Certification can help ensure safety, performance, and trust. Yet, current certification and standards are inconsistent, incomplete, and lack rigor. A project coordinated through Arizona State University is examining existing schemes (Box 6-2). Regarding safety, the need for enormous volumes of storage will affect everyone, now and in future generations (Arcusa, 2022). Regarding performance, removal activities must function as promised. Regarding trust, carbon sequestration moves odorless, colorless gas that may have no discernable impact for years or decades. Moreover, certification must be conducted within a recognized and trusted framework. Potential consequences from improper certification include wasting time and resources, enabling scams/fraud, harming communities and the environment, and failing to address climate change.

Although CDR is emerging as an important climate agenda item, other decarbonization options will play a substantial role in reducing net emissions, including zero-carbon energy sources such as renewables and nuclear energy. Needed are efficiency improvements across the whole energy system, especially in end use, as well as new climate-friendly lifestyles and behaviors. As described in Box 5-1, Copenhagen aims to become carbon neutral by 2025 and to rebuild with livability linked to sustainability, by reducing energy consumption, reorienting energy production to wind and other renewable sources, and increasing green mobility. AR6 states that measures that promote walkable urban areas,

combined with electrification and renewable energy, can improve health through cleaner air and enhanced mobility (IPCC, 2022). Design and management of urban areas play important roles in achieving decarbonization goals.

This grand transformation toward full decarbonization of energy systems and end use is not only about technology and economics. It is also about people, societies, and values and behaviors. Technology is an integral part of society and a

collective expression of sundry individual choices (Nakicenovic and Lund, 2021; Nakicenovic, 2022).

KEY RESERCH PRIORITIES FOR DECARBONIZATION

The committee proposes the following key priorities for research to operationalize sustainable development to contribute to decarbonization:

• Examine fundamental science for ocean- and nature-based CDR, including chemical pathways, microbiome variability and durability of soil

• sequestration, forest and ocean-based proposals, and suitable reservoirs for underground or deep sea storage.¹
• Conduct standards setting for monitoring, reporting, and verification techniques for various pathways.
• Explore acceptable levels of uncertainty in certification in both technical and social dimensions including intergenerational justice.
• Improve the understanding of possible impacts on biodiversity, land, or ocean use for food or other unintended consequences such as tipping points for carbon sinks becoming sources.
• Examine technologies that enable large-scale deployment of carbon capture, utilization, and storage, with an emphasis on durability and ways to scale-up. Examples include the Sleipner T carbon dioxide treatment platform and the carbon capture plant in Iceland (Panko, 2021).

POSSIBLE ACTIONABLE STEPS FOR DECARBONIZATION

The committee identifies the following possible actionable steps to operationalize sustainable development to contribute to decarbonization:

• The U.S. government and other national governments could identify strategies for CDR that are place-based, community embraced, and environmentally and intergenerationally just.
• The U.S. government could build on the current U.S. $1 billion allocated for the four regional Direct Air Capture hubs (DOE, 2022) to establish other CDR demonstration projects, such as biochar in concrete, asphalt, and soil, as well as global satellite forest monitoring.
• The U.S. government and other national governments could set a flue point capture target of $50/tonne for hard to abate industries, including establishing an international prize competition. An example includes the $100 million Prize for Carbon Removal initiative (XPrize Foundation, 2022).
• The U.S. government and other national governments could ramp up research, development, demonstration, and deployment (RDD&D) for all forms of CDR, as companies are increasing their investments for decarbonization efforts (Judge, 2022).
• The U.S. government and other national governments could play a leadership role in international collaboration and co-funding of research, provide international incentives for ethical deployment and scale-up, and propose an international framework for standards and MRV to deter

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¹ The National Academies has released a number of in-depth studies on many of these topics, including NASEM. 2022. A Research Strategy for Ocean-based Carbon Dioxide Removal and Sequestration. Washington, DC: The National Academies Press. https://doi.org/10.17226/26278; and NASEM. 2019. Negative Emissions Technologies and Reliable Sequestration: A Research Agenda. Washington, DC: The National Academies Press. https://doi.org/10.17226/25259.

• national and corporate “greenwashing.” Although groups such as Frontier² and First Movers³ are using procurement strategies to accelerate carbon removal, standards are needed. Relevant examples include Climate Bonds Certification (2022) and Green Bond Principles (2022). Bilateral city exchanges, city networks, and academic institutions could encourage collaborative research opportunities in emerging countries.
• The U.S. government could enhance federal coordination between agencies, such as the U.S. Department of Agriculture, Department of Energy, Department of Interior, Environmental Protection Agency, General Services Administration, and Department of Defense relating to incentives, MRV, siting, and accounting.
• The U.S. government could expand attribute-focused rather than prescriptive tax incentives, such as focusing on sequestration durability instead of pathway-specific technology.
• Federal and state governments and international coalitions, working with multi-sector partnerships such as the Global Carbon Removal Partnership,⁴ could use procurement to catalyze and set standards for private-sector investments, promote incentives for sequestration and not just capture, and utilize lessons learned from partnerships (see case studies) to engage in international dialog on ethics and environmental justice in CDR, as well as framework and standards for MRV.
• Governments, the private sector, and nongovernmental organizations could work together to promote decarbonization in agriculture, industry, and energy production, including by building carbon-neutral cities, strengthening climate education and engagement, and encouraging low-carbon lifestyles for mobility, housing, and consumption.

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² See https://frontierclimate.com.

³ See https://www.protocol.com/first-movers-coalition-climate-davos.

⁴ See https://carbonremovalpartnership.net.

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