Avoiding the most severe consequences of climate change will require significant innovation, and a range of market, technological, and policy solutions. To meet critical midterm and 2050 reduction targets, analyses clearly point to the need for carbon dioxide removal (CDR), the process of removing carbon dioxide from the atmosphere and durably storing it in terrestrial or geologic reservoirs or products. CDR solutions include both nature-based approaches (e.g., afforestation, reforestation, biochar, soil carbon sequestration) and technological and industrial approaches (e.g., bioenergy with carbon capture and storage, direct air capture). In our recent Closer Look paper, Carbon Dioxide Removal: Pathways and Policy Needs, we assess the role of CDR approaches in a comprehensive decarbonization plan, considering their respective potentials and barriers for large-scale deployment.
Importantly, CDR solutions are not a substitute for emissions reductions, which remain an urgent priority. However, a number of recent studies—including the landmark 2018 Intergovernmental Panel on Climate Change (IPCC) Special Report on Global Warming of 1.5 Degrees C—have emphasized the need for CDR to reach global climate objectives. All IPCC mitigation pathways that limit global warming to 1.5 degrees C by 2100 use CDR in their projected models. Similarly, the National Academy of Sciences has estimated that to meet the Paris Agreement goals, 10 gigatons of carbon dioxide will need to be removed globally each year through 2050, with 20 gigatons of carbon dioxide removed each year from 2050 to 2100.
CDR solutions are key in the transition to a decarbonized future because they can help hard-to-decarbonize sectors address unavoidable emissions. For example, industrial processes such as limestone calcination would still emit carbon dioxide even if they are powered by clean energy sources. Strategies to decarbonize these sectors include CDR and negative emissions. In other cases, reducing the last few percentage points of emission might cost enough to create economic hardships for businesses and consumers. Compensating for those emissions with CDR, as part of a clear net-zero mandate, can provide environmental and economic benefits.
Industry must begin an unprecedented level of development and deployment now, so CDR projects can be realized at the necessary scale by mid-century. Whether industry can scale CDR solutions to the levels needed to have a significant impact on climate mitigation, depends on numerous factors, including:
- the potential a given technique or technology has to remove carbon dioxide from the atmosphere
- cost effectiveness
- level of readiness to be deployed
- how quickly the carbon sink reaches capacity
- permanence of the carbon removals.
Nature-based solutions, while not without challenges, are largely affordable, readily available, and have an important role to play in both the near- and long-term. Technological solutions may be more scalable and more permanent but will require further development to reach commercial viability. Given the variation in removal potential, cost, readiness, and other factors, the United States will need a portfolio of CDR solutions to maximize the chances of meeting its climate targets. Policy can play a vital role in making such a portfolio a reality.
Policies to address economic and technological barriers for large-scale deployment of CDR solutions include a combination of “technology-push” and “demand-pull” policies. Technology-push policies can enhance the development of CDR technologies through research, development, and demonstration funding as well as developing carbon dioxide transport and storage infrastructure. Demand-pull policies include market-based instruments such as carbon pricing, allowing CDR projects to participate in low-carbon standards (a clean energy standard or a low-carbon fuel standard), fostering markets for utilization of the captured carbon dioxide. Other policies would also be necessary to foster trust and long-term support for CDR. These include establishing rigorous and credible life-cycle analyses for CDR solutions, and reducing uncertainties related to long-term carbon storage and liability.
In order to meet domestic and international climate goals, it’s critical that the United States deploy an unprecedented combination of nature-based and technological CDR solutions. The scientific community has demonstrated how both suites of technologies are necessary as we creep ever closer to points of no return. Targeted policies can not only help ensure that CDR solutions are available at the scales necessary and give U.S. companies a competitive advantage in developing and exporting breakthrough technologies, but also help to cement and restore U.S. leadership in the global climate challenge.