CO₂-removal News

Peer-reviewed Publications

Mwaura et al. (2024): Do smallholders have a role to play in atmospheric greenhouse gas removal? Insights from western Kenya

Francis M. Mwaura, Margaret W. Ngigi, Gideon Obare IN: Scientific African 24, e02206, https://doi.org/10.1016/j.sciaf.2024.e02206

Despite consensus by the international community on the need for setting targets for reducing emissions or enhancing removal of greenhouse gases, comprehensive strategies for enumerating smallholders’ roles are yet to be designed and tested. Moreover, although smallholders’ role as net greenhouse gas removers has been speculated, evidence of this fact is necessary. A survey of 380 smallholders involved in maize-farming system in four sub-counties of western Kenya representing heterogeneity in agro-ecological zones and postulated biomass cooking energy access and demand was undertaken. 

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Peer-reviewed Publications

Suhrhoff et al. (2024): A tool for assessing the sensitivity of soil-based approaches for quantifying enhanced weathering: a US case study

Tim Jesper Suhrhoff, Tom Reershemius, Jiuyuan Wang, Jacob S. Jordan, Christopher T. Reinhard, Noah J. Planavsky IN: Frontiers in Climate, https://doi.org/10.3389/fclim.2024.1346117

Enhanced weathering (EW) of silicate rocks spread onto managed lands as agricultural amendments is a promising carbon dioxide removal (CDR) approach. However, there is an obvious need for the development of tools for Measurement, Reporting, and Verification (MRV) before EW can be brought to scale. Shifts in the concentration of mobile elements measured in the solid phase of soils after application of EW feedstocks can potentially be used to track weathering and provide an estimate of the initial carbon dioxide removal of the system. To measure feedstock dissolution accurately it is necessary to control for the amount of feedstock originally present in the sample being analyzed. This can be achieved by measuring the concentration of immobile detrital elements in soil samples after feedstock addition. 

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Podcasts

Plan Sea: Ocean Interventions to Address Climate Change

podcast by Wil Burns & Anna Medlener (Institute for Carbon Removal Law & Policy, American University), 1h

In this episode Lennart Bach, at the Institute for Marine and Antarctic Studies, University of Tasmania, and Veronica Tamsitt, Head of Oceanography at the mCDR MRV company, Submarine, discuss some of the most pertinent issues to assessing the potential role of Ocean Iron Fertilization (OIF) in a marine CDR portfolio, including costs, risks, and legal considerations.

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Peer-reviewed Publications

Gama et al. (2024): Process Operability Analysis of Membrane-Based Direct Air Capture for Low-Purity CO2 Production

Vitor Gama, Beatriz Dantas, Oishi Sanyal, Fernando V. Lima IN: ACS Engineering Au, https://doi.org/10.1021/acsengineeringau.3c00069

This study investigates the feasibility of using membranes as direct air capture (DAC) technology to extract CO2 from atmospheric air to produce low-purity CO2. In this work, a two-stage hollow fiber membrane module process is designed and modeled using the AVEVA Process Simulation platform to produce a low-purity (≈5%) CO2 permeate stream. Such low-purity CO2 streams could have several possible applications such as algae growth, catalytic oxidation, and enhanced oil recovery. An operability analysis is performed by mapping a feasible range of input parameters, which include membrane surface area and membrane performance metrics, to an output set, which consists of CO2 purity, recovery, and net energy consumption.

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Peer-reviewed Publications

Bona et al. (2024): Using the Canadian Model for Peatlands (CaMP) to examine greenhouse gas emissions and carbon sink strength in Canada’s boreal and temperate peatlands

Kelly A. Bona, Kara L. Webster, Dan K. Thompson, Oleksandra Hararuk, Gary Zhang, Werner A. Kurz IN: Ecological Modelling, 490, 110633, https://doi.org/10.1016/j.ecolmodel.2024.110633

This study applied the Canadian Model for Peatlands (CaMP) to 63.9 million hectares of peatlands within boreal and temperate ecozones of Canada to assess the trends in atmospheric carbon (C) emissions and removals and C sequestration over 30 years (1990–2019). While this research is the first to produce estimates of C sequestration and greenhouse gas emission and removal rates across such a large area of Canada, further research is required across peatland types and ecozones to improve parameterization, validation, and process representations. The results stress the importance of ecozone-specific analyses and accounting for infrequent large fire years and fire risk in land management policy and carbon accounting.

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Peer-reviewed Publications

Silcox & Chandran (2024): Demand-side flexibility enables cost savings ina reversible pH-swing electrochemical processfor oceanic CO2 removal

Rachel Silcox, Rohini Bala Chandran IN: Cell Reports Physical Science, 5, https://doi.org/10.1016/j.xcrp.2024.101884

A reversible pH-shifting seawater process uses hydrogen and redox salt to extract CO2, generating and consuming power during acidification and basification, respectively. An equivalent circuit model predicts performance dependent on key transport and thermodynamic parameters. The need to overcome mass-transport limitations, particularly liquid boundarylayer diffusion, is crucial for industrial current densities. Energy-intensity calculations indicate this process is competitive with prior oceanic CO2 removal processes and even with direct air capture, when pumping energy cost is eliminated.

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Peer-reviewed Publications

Abegg et al. (2024): Expert Insights into Future Trajectories: Assessing Cost Reductions and Scalability of Carbon Dioxide Removal Technologies

Manon Abegg, Zeynep Clulow, Lucrezia Nava, David M. Reiner IN: Frontiers in Climate, doi:10.3389/fclim.2024.1331901

This study explores the future costs and scalability of DACCS and BECCS to advance net-zero goals. The authors analyze expert opinions on these technologies‘ potential costs and deployment scales for 2030, 2040, and 2050. Data was collected from 34 experts, comprising 21 DACCS and 13 BECCS specialists. They provided 90% confidence interval estimates and ‚best estimates‘ for future costs and deployment under two International Energy Agency (IEA) policy scenarios -Stated Policies (STEPS) and Net Zero Emissions by 2050 (NZE).

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Peer-reviewed Publications

Robertson et al. (2024): Polymer Sorbent Design for the Direct Air Capture of CO2

Mark Robertson, Jin Qian, Zhe Qiang IN: ACS Applied Polymer Materials, https://doi.org/10.1021/acsapm.3c03199

Here, direct air capture (DAC) represents an essential need for reducing CO2 concentration in the atmosphere to mitigate the negative consequences of greenhouse effects, involving systems that can reversibly adsorb and release CO2, in which polymers have played an integral role. This work provides insights into the development of polymer sorbents for DAC of CO2, specifically from the perspective of material design principles. The authors discuss how physical properties and chemical identities of amine-containing polymers can impact their ability to uptake CO2, as well as be efficiently regenerated. 

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Peer-reviewed Publications

Ünal et al. (2024): The nexus between direct air capture technology and CO2 emissions in the transport sector

Emre Ünal, Alexander Ryota Keeley, Nezir Köse, Andrew Chapman, Shunsuke Managi IN: Applied Energy, 363, 123112, https://doi.org/10.1016/j.apenergy.2024.123112

British Columbia provides a substantial chance to examine emissions that were produced after the DAC actions were put into place in 2015. In this study, the difference-in-differences methodology is employed for the very first time to compare the emissions that are produced by the transport sectors in British Columbia with those emitted by other provinces in Canada. The role that GDP and population play in the release of emissions is also taken into consideration in this paper. Based on the research results, it can be observed that the implementation of DAC initiatives has yielded notable effects. 

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Peer-reviewed Publications

Nature – Yu et al. (2024): Maximizing carbon sequestration potential in Chinese forests through optimal management

Zhen Yu, Shirong Liu, Haikui Li, Jingjing Liang, Weiguo Liu, Shilong Piao, Hanqin Tian, Guoyi Zhou, Chaoqun Lu, Weibin You, Pengsen Sun, Yanli Dong, Stephen Sitch, Evgenios Agathokleous IN: Nature Communications, 15, https://doi.org/10.1038/s41467-024-47143-5

Forest carbon sequestration capacity in China remains uncertain due to underrepresented tree demographic dynamics and overlooked of harvest impacts. In this study, the authors employ a process-based biogeochemical model to make projections by using national forest inventories, covering approximately 415,000 permanent plots, revealing an expansion in biomass carbon stock by 13.6 ± 1.5 Pg C from 2020 to 2100, with additional sink through augmentation of wood product pool (0.6-2.0 Pg C) and spatiotemporal optimization of forest management (2.3 ± 0.03 Pg C). 

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