Jahr: 2023

Science-Policy Documents

Bednar et al. (2023): Beyond emissions trading to a negative carbon economy: a proposed carbon removal obligation and its implementation

Johannes Bednar, Justin Macinante, Artem Baklanov, James Hall, Fabian Wagner, Navraj S. Ghaleigh, Michael Obersteiner IN: Climate Policy, https://doi.org/10.1080/14693062.2023.2276858

A policy framework based on ‘carbon removal obligations’ (CROs) has been proposed to respond to concerns about the financial and fiscal viability, the lack of incentives for CDR uptake, as well as the physical and technological risks associated with any climate mitigation scenario that relies on large scale CDR. Here the authors propose an updated and improved CRO policy framework, consisting of two core elements: the ‘principal CRO mechanism’ obliges emitters of a tonne of CO2 to remove a tonne of CO2 at the time of maturity of the CRO. On top of this obligation, CRO holders need to pay a fee for the temporary storage of CO2 in the atmosphere.

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Peer-reviewed Publications

Perkins et al. (2023): Toward quantification of the feasible potential of land-based carbon dioxide removal

Oliver Perkins, Peter Alexander, Almut Arneth, Calum Brown, James D.A. Millington, Mark Rounsevell IN: One Earth, https://doi.org/10.1016/j.oneear.2023.11.011

The authors set out research frameworks to work toward quantification of this feasible potential. They first argue that quantifying the feasible potential will substantially reduce current assessed CDR potential. Second, the authors demonstrate how transdisciplinary methods are improving understanding of feasibility constraints on land-based CDR. Third, they explore frameworks for synthesizing these advances during the next IPCC assessment process. The authors conclude that the research community should carefully consider the use of techno-economic CDR assessments in evidence for policymakers.

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Peer-reviewed Publications

Goldberg et al. (2023): Upscaling DAC Hubs with Wind Energy and CO2 Mineral Storage: Considerations for Large-Scale Carbon Removal from the Atmosphere

David S. Goldberg, Sara Nawaz, James Lavin, Angela L. Slagle IN: Environmental Science & Technologie, https://doi.org/10.1021/acs.est.3c03492

The authors consider one location for theoretical scale-up of a DAC hub: the Kerguelen plateau in the Southern Indian Ocean which has high-potential renewable energy resources (wind) and large volumes of basalt rock for mineral storage. With consistent wind, previous studies indicate a hub in this location could collect approximately 75 Mt of CO2 annually, with conservative storage resources for 150–300 Mt of CO2 each year. Even with its immense wind and storage potentials, 14 Kerguelen-scale hubs would be needed to capture and store 1 Gt of CO2 per year. This brings into focus the important social, economic, and environmental trade-offs that must be considered in finding an acceptable balance between climate solutions, renewable energy requirements, and nature. 

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Peer-reviewed Publications

Momeni et al. (2024): Direct air capture of CO2 using green amino acid salts

Arash Momeni, Rebecca V. McQuillan, Masood S. Alivand, Ali Zavabeti, Geoffrey W. Stevens, Kathryn A. Mumford IN: Chemical Engineering Journal, 480, 147934, https://doi.org/10.1016/j.cej.2023.147934

In this study, various green amino acid salts performances in a DAC system were explored using non-porous hollow fiber membrane contactors (HFMCs). Two DAC absorption and desorption apparatuses were developed. For the DAC-absorption unit, the thermodynamic and kinetic behavior of five types of aqueous amino acid salt solutions were evaluated in long-term operations.

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Peer-reviewed Publications

Van Der Bauwhede et al. (2024): Accelerated weathering of silicate rock dusts predicts the slow-release liming in soils depending on rock mineralogy, soil acidity, and test methodology

Robrecht Van Der Bauwhede, Bart Muys, Karen Vancampenhout, Erik Smolders IN: Geoderma, 441, 116734, https://doi.org/10.1016/j.geoderma.2023.116734

This study addressed these questions by comparing and validating three accelerated weathering tests for their capacity to predict the gradual liming effects in a two-year outdoor mesocosm. Five commercial RDs (two basalts, phonolite, foidite, and trachy-andesite) were tested in four acidified forest soils varying in initial pH, in texture and associated pH buffer power.

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Peer-reviewed Publications

Nature – Fu et al. (2023): Substantial blue carbon sequestration in the world’s largest seagrass meadow

Chuancheng Fu, Sofia Frappi, Michelle Nicole Havlik, Wells Howe, S. David Harris, Elisa Laiolo, Austin J. Gallagher, Pere Masqué, Carlos M. Duarte IN: Communication Earth & Environment, 4, https://doi.org/10.1038/s43247-023-01154-0

Here, the authors sampled 10 seagrass meadows across an extensive island chain in The Bahamas. They estimate that Bahamas seagrass meadows store 0.42–0.59 Pg organic carbon in the top-meter sediments with an accumulation rate of 2.1–2.9 Tg annually, representing a substantial global blue carbon hotspot. Autochthonous organic carbon in sediments decreased from ~1980 onwards, with concomitant increases in cyanobacterial and mangrove contributions, suggesting disturbance of seagrass ecosystems, likely caused by tourism and maritime traffic activities. This study provides seagrass blue carbon data from a vast, understudied region and contributes to improving climate action for The Bahamas and the Greater Caribbean region.

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Reports

Report: Roads to Removal in the United States

Roads2Removal, December 2023

The Roads to Removal (R2R) report is a national collaborative effort by more than 68 scientists, and 13 institutions that examines regionally specific opportunities to address the pressing issue of climate change and the urgent need to remove CO2 from the atmosphere and store it at the gigaton scale. R2R researchers evaluated various techniques for CDR at the county level based on factors such as feasibility, capacity, impact, and cost. Chapters in the report include Forests, Soils, Biomass Carbon Removal and Storage (BiCRS) and Direct Air Capture (DAC), as well as the feasibility and costs of transporting CO2 and storing it underground. The report also examines the environmental and socioeconomic co-benefits and the significance of avoiding and reducing negative impacts on people and the environment.

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Peer-reviewed Publications

Arwa and Schell (2024): Batteries or silos: Optimizing storage capacity in direct air capture plants to maximize renewable energy use

Erick O. Arwa, Kristen R. Schell IN: Applied Energy 355, 2024, 122345, https://doi.org/10.1016/j.apenergy.2023.122345

DAC is an energy intensive chemical process, whose designs are currently incompatible with intermittent renewable energy (RE) sources. This research develops a model to enable the flexible operation of DAC, to maximize RE usage. A new model of the chemical process flow of a liquid solvent DAC that includes silos to store CaCO3 and CaO is developed. A linear programming optimization model that minimizes energy costs while achieving the CO2 capture targets of the DAC plant is developed. Scenario analysis establishes the storage silo size and battery storage size needed to reduce renewable energy curtailment to zero for a given RE profile.

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Peer-reviewed Publications

Li et al. (2024): The interactions between olivine dissolution and phytoplankton in seawater: Potential implications for ocean alkalinization

Canru Li, Xiangdong Liu, Yan Li, Yuan Jiang, Xianghui Guo, David A. Hutchins, Jian Ma, Xin Lin, Minhan Dai IN: Science of The Total Environment, 912, 168571, https://doi.org/10.1016/j.scitotenv.2023.168571

Olivine is considered the most promising mineral for ocean alkalinization enhancement due to its theoretically high CO2 sequestration efficiency. Olivine dissolution has been predicted to alter marine phytoplankton communities, however, there is still a lack of experimental evidence. The olivine dissolution process in seawater can be influenced by a range of factors, including biotic factors, which have yet to be explored. In this study, the authors cultivated two diatoms and one coccolithophore with and without olivine particles to investigate their interactions with olivine dissolution.

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