Source: Climeworks (Hinwil, Switzerland)
Policymakers, innovators, and climate champions alike are laboring to create sustainable systems that protect the planet and lower our carbon footprint. With nearly every country signed onto the Paris agreement, we are faced with a problem larger than decarbonizing industries and adopting more sustainable lifestyles: we must actively try to alter the chemistry of our atmosphere to pre-industrial levels.
The National Academy of Sciences, Engineering, and Medicine (NASEM) found that climate goals to prevent warming beyond two-degrees Celsius require 10 billion tonnes of annual CO2 removal before 2050 (with approximately double that annual removal until 2100) [1]. For comparison, 10 billion tonnes of CO2 is equal to two years of the United States’ emissions.
Negative emissions technologies (NETs) are a class of solutions that remove CO2 from the atmosphere at rates which can be used to address the climate crisis. NETs systems rely on fundamental principles from biology to geology, chemistry, and other cardinal sciences [2]. Biological principles are relevant in systems with improved forestry practices and land management to maintain and increase the amount of CO2 inhaled by natural processes. Geologists and engineers collaborate to innovate around the natural chemistry of minerals that convert atmospheric CO2 deposits into carbonates. Chemistry is key in direct air capture (DAC) technologies: a type of NETs where atmospheric CO2 is passed over reactive chemicals that catch the CO2 and allow ‘clean air’ to flow through.
The National Academy of Sciences, Engineering, and Medicine (NASEM) found that climate goals to prevent warming beyond two-degrees Celsius require 10 billion tonnes of annual CO2 removal before 2050 (with approximately double that annual removal until 2100) [1]. For comparison, 10 billion tonnes of CO2 is equal to two years of the United States’ emissions.
Negative emissions technologies (NETs) are a class of solutions that remove CO2 from the atmosphere at rates which can be used to address the climate crisis. NETs systems rely on fundamental principles from biology to geology, chemistry, and other cardinal sciences [2]. Biological principles are relevant in systems with improved forestry practices and land management to maintain and increase the amount of CO2 inhaled by natural processes. Geologists and engineers collaborate to innovate around the natural chemistry of minerals that convert atmospheric CO2 deposits into carbonates. Chemistry is key in direct air capture (DAC) technologies: a type of NETs where atmospheric CO2 is passed over reactive chemicals that catch the CO2 and allow ‘clean air’ to flow through.
Source: Carbon Brief
NETs span a large range of solutions from many areas of science and technology, but no single approach to negative emissions is a silver bullet. Each option comes with a unique set of constraints that compliment specific scenarios and geographic locations. Forestry and land management practices may be best suited for areas with arable land that is not used for agriculture. Geologic solutions should be deployed where these minerals are naturally found to avoid transportation emissions. Direct air capture is most effective where it can be coupled with low-carbon energy like solar, wind, or geothermal technologies [3]. The CDR Primer describes the science, economic evaluation, and geographic siting of NETs technology in an open-source document published by the industry’s leading experts.
NETs can be enticing because they seductively suggest that we do not need to change our habits and lifestyles. Deployed irresponsibly, they can be used to warrant a “business as usual” scenario where emitters do not have to make changes. Leading experts advocate for the deployment of NETs to offset emissions that are particularly hard to avoid [4,5]. Cement and steel manufacturing are exemplary depictions of hard to avoid emissions: together they account for nearly 15% of total global emissions, but neither have low-carbon alternatives that are ready to deploy at an industrial level [6].
NETs can be enticing because they seductively suggest that we do not need to change our habits and lifestyles. Deployed irresponsibly, they can be used to warrant a “business as usual” scenario where emitters do not have to make changes. Leading experts advocate for the deployment of NETs to offset emissions that are particularly hard to avoid [4,5]. Cement and steel manufacturing are exemplary depictions of hard to avoid emissions: together they account for nearly 15% of total global emissions, but neither have low-carbon alternatives that are ready to deploy at an industrial level [6].
Source: CDR Primer, Chapter 1
NASEM emphasized that decision makers must champion sustainability and decarbonization on Earth while helping to deploy NETs to remove billions of tonnes of CO2 every year. NETs represent a wide variety of nature-based solutions and engineered options which should be deployed simultaneously to meet the goal of 10 billion tonnes of removal each year. NETs are not alternatives to decarbonization but a tool that has been identified with the potential to offset hard to avoid emissions.
References
References
- National Academies of Sciences Engineering and Medicine (NASEM) (2019) Negative Emissions Technologies and Reliable Sequestration: A Research Agenda (The National Academies Press, Washington, D.C.) Available at: https://www.nap.edu/catalog/25259/ negative-emissions-technologies-and-reliable-sequestration-a-research-agenda.
- G. Dipple, P. Kelemen, C. Woodall, N. McQueen, J. Wilcox, B. Anderegg, J. Freeman, R.Jacobsen, M. Torn (2021) “The Building Blocks of CDR Systems” CDR Primer, edited by J Wilcox, B Kolosz, J Freeman
- Noah McQueen, Peter Psarras, Hélène Pilorgé, Simona Liguori, Jiajun He, Mengyao Yuan, Caleb M. Woodall, Kourosh Kian, Lara Pierpoint, Jacob Jurewicz, J. Matthew Lucas, Rory Jacobson, Noah Deich, and Jennifer Wilcox (2020) “Cost Analysis of Direct Air Capture and Sequestration Coupled to Low-Carbon Thermal Energy in the United States.” Environmental Science & Technology 54 (12), 7542-7551
- A Bergman & A Rinberg (2021) “The Case for Carbon Dioxide Removal: From Science to Justice” CDR Primer, edited by J Wilcox, B Kolosz, J Freeman
- Wilcox, Jennifer (2020) “The Essential Role of Negative Emissions in Getting to Carbon Neutral” Kleinman Center for Energy Policy
- T. Czigler, S. Reiter, P. Schulze, K. Somers (2020) “Laying the foundation for zero carbon cement” McKinsey.
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Katherine Vaz Gomes is a Ph.D. Candidate in Chemical Engineering at the University of Pennsylvania. At Penn, she is also pursuing a certificate in Energy Management from the Kleinman Center for Energy Policy. Katherine’s research focuses on carbon capture and removal: specifically carbon storage in industrial wastes. Her work includes both experimental and technoeconomic analysis of carbon mineralization. In addition to her work at Penn, Katherine is a science advisor at Carbon Direct Inc where she brings engineering expertise to financial investments. Katherine holds a B.S. in Chemical Engineering and Professional Writing from Worcester Polytechnic Institute.
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