CO2-removal News

Mühlbauer et al. (2025): Assessment of technologies and economics for carbon dioxide removal from a portfolio perspective

Andreas Mühlbauer, Dominik Keiner, Christoph Gerhards, Upeksha Caldera, Michael Sterner, Christian Breyer IN: International Journal of Greenhouse Gas Control, 141, https://doi.org/10.1016/j.ijggc.2024.104297

This study addresses the need for diverse carbon dioxide removal (CDR) portfolios and introduces the LUT-CDR tool, which assesses CDR technology portfolios aligned with hypothetical societal preferences. Six scenarios are described, considering global deployment limitations, techno-economic factors, area requirements, technology readiness, and storage security for various CDR options.

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Nature – Deng et al. (2025): Towards negative carbon footprint: carbon sequestration enabled manufacturing of coral-inspired tough structural composites

Haoxiang Deng, Haixu Du, Ketian Li, Yanchu Zhang, Kyung Hoon Lee, Botong Zheng, Qiming Wang IN: npj Advanced Manufacturing, 2, https://doi.org/10.1038/s44334-024-00012-x

Traditional carbon sequestration methods focus on storing CO2 or converting it into liquid substances. However, natural processes like those found in corals demonstrate superior capabilities by transforming CO2 into robust, load-bearing solids with exceptional mechanical properties. Inspired by coral’s biomineralization, this study introduces an electrochemical manufacturing method that converts CO2 into calcium carbonate minerals around 3D-printed polymer scaffolds.

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Kim et al. (2025): Carbon dioxide removal (CDR) potential in temperate macroalgal forests: A comparative study of chemical and biological net ecosystem production (NEP)

Ju-Hyoung Kim, Hyung Woo Lee, Juhyung Lee, Miok Kim, Kitak Lee, Changsin Kim, Eun Ju Kang, Ye Rim Kim, Yeo Jin Yoon, Soo Bin Lee, Hyun Jeong Kim, Eun Jin Choi, Ho-Sung Yoon, Boseong Kim, Jin Woo Kang, Ji Chul Oh, Jun Ho Kim, Im Ho Choi IN: Marine Pollution Bulletin, 210, https://doi.org/10.1016/j.marpolbul.2024.117327

Accurately estimating the carbon dioxide removal (CDR) potential of macroalgae in natural conditions remains challenging, necessitating the use of multiple independent methods to reduce the uncertainties in these estimates. In this study, the authors compared two methods for estimating net ecosystem production (NEP), a key parameter in determining CDR potential: 1) NEPChem., derived from seawater carbonate chemistry and 2) NEPBiol., based on photorespiratory measurements using benthic tent incubation. This study, conducted in a macroalgal forest dominated by Ecklonia cava, involved simultaneous measurements of NEPChem. and NEPBiol. over a course of one year.

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Nature – Duarte et al. (2025): Carbon burial in sediments below seaweed farms matches that of Blue Carbon habitats

Carlos M. Duarte, Antonio Delgado-Huertas, Elisa Marti, Beat Gasser, Isidro San Martin, Alexandra Cousteau, Fritz Neumeyer, Megan Reilly-Cayten, Joshua Boyce, Tomohiro Kuwae, Masakazu Hori, Toshihiro Miyajima, Nichole N. Price, Suzanne Arnold, Aurora M. Ricart, Simon Davis, Noumie Surugau, Al-Jeria Abdul, Jiaping Wu, Xi Xiao, Ik Kyo Chung, Chang Geun Choi, Calvyn F. A. Sondak, Hatim Albasri, … Pere Masque IN: Nature Climate Change, 2025, https://doi.org/10.1038/s41558-024-02238-1

Here, the authors quantify carbon burial in 20 seaweed farms distributed globally, ranging from 2 to 300 years in operation and from 1 to 15,000 ha in size.

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Nature – Malakar et al. (2025): Navigating stakeholder heterogeneity in carbon dioxide removal governance

Yuwan Malakar, Kerryn Brent, Audrey Bester, John Gardner, Will Howard, Andrew Lenton IN: Nature Reviews Clean Technology, 1, https://doi.org/10.1038/s44359-024-00006-0

Responsible carbon dioxide removal (CDR) governance will require engagement with numerous stakeholders who have differing agendas, roles and influence in the CDR landscape. However, there is little guidance on how to understand and appropriately engage with this heterogeneous set of stakeholders. In this Perspective, the authors discuss how to navigate stakeholder heterogeneity and engagement in CDR, using a framework based on multi-level perspective and stakeholder theory.

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Nature – Ascenzi et al. (2025): Increased but not pristine soil organic carbon stocks in restored ecosystems

Irene Ascenzi, Jelle P. Hilbers, Marieke M. van Katwijk, Mark A. J. Huijbregts, Steef V. Hanssen IN: Nature Communications, 16, https://doi.org/10.1038/s41467-025-55980-1

It is unclear how much soil organic carbon (SOC) stocks recover across different restored ecosystems. Here, the authors show SOC recovery in different contexts globally by consolidating 41 meta-analyses into a second-order meta-analysis.

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Javadi et al. (2024): The impact of regional resources and technology availability on carbon dioxide removal potential in the United States

Parisa Javadi, Patrick O’Rourke, Jay Fuhrman, Haewon McJeon, Scott C Doney, William Shobe, Andrés F Clarens IN: Environmental Research: Energy 1, 045007, https://doi.org/10.1088/2753-3751/ad81fb

Using the global change analysis model for the United States (GCAM-USA), the authors modeled six classes of CDR and explored their potential using four scenarios: a scenario where all the CDR pathways are available (Full Portfolio), a scenario with restricted carbon capture and storage (Low CCS), a scenario where the availability of bio-based CDR options is limited (Low Bio), and a scenario with constraints on enhanced rock weathering (ERW) capabilities (Low ERW). 

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Xu et al. (2024): Investigating CO₂ sequestration via enhanced rock weathering: Effects of temperature and citric acid on dolomite and basalt

Qiao Xu, Feifan Zhang, Fanhao Song, Hongyan Guo, Xiaozhi Wang, Fenfen Bi, Meiling Xu IN: Journal of Cleaner Production 485, 144414, https://doi.org/10.1016/j.jclepro.2024.144414

Enhanced rock weathering is a promising approach for CO₂ sequestration, regulated by biotic factors such as root exudates and abiotic factors like temperature. Using dolomite and basalt, this study examined the CO2 sequestration potential of ERW as affected by elevated temperature and citric acid, and the effects on soil C dynamics and heavy metal release in a 90-day leaching experiment.

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Tyka (2025): Efficiency metrics for ocean alkalinity enhancements under responsive and prescribed atmospheric pCO2 conditions

Michael D. Tyka IN: Biogeosciences 22, 341-353, https://doi.org/10.5194/bg-22-341-2025

Ocean alkalinity enhancement (OAE) and direct ocean removal (DOR) are emerging as promising technologies for enacting negative emissions. The long equilibration timescales, potential for premature subduction of surface water parcels, and extensive horizontal transport and dilution of added alkalinity make direct experimental measurement of induced CO2 uptake challenging. Therefore, the challenge of measurement, reporting, and verification (MRV) will rely to a great extent on general circulation models, parameterized and constrained by experimental measurements. This paper examines the commonly used metrics of OAE efficiency, their exact physical meanings, the assumptions inherent in their use, and the relationship between them.

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Mesnage et al. (2025): Porous biochar for improving the CO2 uptake capacities and kinetics of concrete

Matthieu Mesnage, Rachelle Omnée, Johan Colin, Hamidreza Ramezani, Jena Jeong, Encarnacion Raymundo-Piñero IN: Cement and Concrete Composites 157, 105932, https://doi.org/10.1016/j.cemconcomp.2025.105932

Carbonation is a natural process in concrete where atmospheric CO2 diffuses into the pores of the material and reacts with cement hydrates to form calcium carbonate. Although this process can help to sequester atmospheric CO2 and mitigate rising levels in urban areas, it slows down over time, resulting in low CO2 uptake over the service life of concrete. This study proposes a sustainable method to improve carbonation kinetics and CO2 capture in cement materials by incorporating highly porous biochar.

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