CO2-removal News

Ishaq & Crawford (2025): Negative Emission Technologies: A Way Forward?

Haris Ishaq and Curran Crawford, IN: RSC Sustainability, https://doi.org/10.1039/D5SU00162E

This review systematically evaluates the current landscape, technical performance, and scalability of key NETs, including Bioenergy with Carbon Capture and Storage (BECCS), Direct Air Carbon Capture and Storage (DACCS), afforestation, soil carbon sequestration and biochar, enhanced weathering, and ocean-based methods. Technological advancements required are analyzed to highlight and enhance the efficiency, scalability, resource requirements (land, water, and minerals), and economic viability of these solutions. The interplay between NETs and existing emissions reduction strategies is critically examined, emphasizing the need for synergies that maximize overall climate benefits while minimizing resource competition. Comparative analyses highlight differences in technological readiness, energy use, and environmental impacts, offering insights into the practical and theoretical limits of CO₂ sequestration for each approach. The review also explores energy balances, cost structures, and life-cycle assessments (LCA), identifying bottlenecks in deployment and potential areas for innovation to enhance efficiency and reduce costs. Additionally, the authors evaluate the current policy frameworks that support NET development, identifying key challenges in both governance and measurement/reporting/verification (MRV) that must be addressed to facilitate widespread deployment.

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Winkler et al. (2025): Exploring Key Dimensions of Policy Instruments for Carbon Dioxide Removal

Malte Winkler, Soyoung, Antonia Holland-Cunz, Matthias Honegger, Matthias Poralla, Alicia Vollmer & Axel Michaelowa, IN: Climate Policy, https://doi.org/10.1080/14693062.2025.2521118

This article examines several non-market policy instruments through a new CDR-specific assessment framework across four dimensions: feasibility, climate effectiveness, impacts on individuals and society, and the ratio and distribution of impacts. Four theoretical scenarios, heterogeneous in assumed time horizon, spatial coverage, and utilized non-market policy instrument, are evaluated: (1) a technology-specific Carbon Contract for Difference in the EU; (2) an internationally funded capacity-building campaign for Brazilian farmers to utilize voluntary carbon markets; (3) a global carbon takeback obligation for fossil fuel producers; and (4) a national corporate tax exemption for Direct Air Capture (DAC) plant setup and operation.

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Hao et al. (2025): Enhanced Carbon Sequestration Potential Following Sediment Dredging in River Ecosystems: Insights into CO₂ Fluxes, Phytoplankton, and Carbon Fixation Pathway Responses

Zhuo Hao, Shibo Chen, Qingwen Zhang, Bing Liu, Shanghong Chen, IN: Environmental Science & Technology, https://doi.org/10.1021/acs.est.5c05177

River systems play crucial roles in the global carbon balance; however, the environmental consequences of sediment dredging on carbon dioxide (CO₂) emissions and carbon sequestration potential remain poorly understood. This study presents the first systematic investigation linking sediment dredging to long-term carbon sequestration dynamics in river ecosystems, addressing critical uncertainties in anthropogenic impacts on aquatic carbon balance. Over a three-year period, dredging significantly altered CO₂ flux (fCO₂) and dissolved CO₂ partial pressure (pCO₂), with pronounced seasonal variability driven by dissolved organic carbon as a key predictor.

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Filahi et al. (2025): Toward Energy-Efficient Greenhouse CO₂ Enrichment: Advancements and Challenges in Direct Air Capture with Solid Sorbents

Ismail Filahi, Ayalew H. Assen, Mohammed Ouikhalfan, Karim Adil, Youssef Belmabkhout, IN: Energy & Fuels, https://doi.org/10.1021/acs.energyfuels.5c02235

This Review highlights recent advances in DAC solid sorbents, including zeolites, metal–organic frameworks (MOFs), ion-exchange resins, and amine-modified mesoporous solids, with a focus on key performance metrics such as adsorption capacity, stability, regeneration efficiency, and scalability in a greenhouse facilities context. Additionally, this Review compares the energy and cost profiles of DAC-enhanced CO₂ enrichment against conventional methods. By outlining both recent progress and persistent challenges, this Review aims to provide insights into the potential of DAC as a sustainable pathway to CO₂ enrichment in greenhouse cultivation.

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De Castro et al. (2025): Ocean liming effect on a North Atlantic microbial community: changes in composition and rates

Inês De Castro, Susana C. Ribeiro, Antonio Miguel Louvado, Newton Carlos Marcial Gomes, Mário Cachão, Eduardo Brito De Azevedo, Joana Barcelos E Ramos, IN: Frontiers in Marine Science, DOI: 10.3389/fmars.2025.1602158

Within OAE, ocean liming—the addition of quicklime (CaO) or hydrated lime (Ca(OH)₂)—can not only remove CO₂ from the atmosphere but potentially counteract the effects of ocean acidification. Although quite attractive, these technologies have yet to be tested regarding ecological safety and efficacy. Here the authors report the impacts of ocean liming on the abundance, composition and extracellular enzymatic activity (EEA) rates of a North Atlantic planktonic community.

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Meyer zu Drewer et al. (2025): Pyrogenic Carbon and Carbonating Minerals for Carbon Capture and Storage (PyMiCCS) Part I: Production, Physico-Chemical Characterization and C-Sink Potential

Johannes Meyer zu Drewer, Maria-Elena Vorrath, Thorben Amann, Jens Hartmann, María De La Rosa, Jens Möllmer, Sara Maria Pérez-Dalí, William Meredith, Clement Uguna, Colin Snape, Claudia Irene Kammann, Hans-Peter Schmidt, Nikolas Hagemann, IN: Frontiers in Climate, DOI: 10.3389/fclim.2025.1631368

The combination of pyrogenic carbon (PyC) and enhanced weathering of minerals (Mi) for carbon capture and storage (CCS), in short PyMiCCS, presents a potentially synergetic and multifunctional approach that may be achieved by either co-application of biochar and rock powder to soils or the co-pyrolysis of biomass and rock powder before soil use. Here, the authors mixed biomass (wood; straw) with 10 to 50 wt% silicate rock powder (namely basanite or diabase) for co-pyrolysis to produce twelve different rock-enhanced (RE-) biochars. Products were subject to physico-chemical characterization, including an assessment of carbon yield and proxies for biochar persistence.

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Nature – Bindl et al. (2025): Risks of relying on uncertain carbon dioxide removal in climate policy

Matilyn Bindl, Morgan R. Edwards and Ryna Yiyun Cui, IN: Nature Communications, https://doi.org/10.1038/s41467-025-61106-4

What are the consequences of planning for levels of CDR today that may differ from those realized in the future? Here, the authors combine decision analysis and a global integrated assessment model (GCAM) to quantify the climate, technology, economic, and equity outcomes of planning for high or low CDR adoption under uncertainty.

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Ahmad et al. (2025): Bioenergy with Carbon Capture and Storage (BECCS): Case Study of Pakistan (2015‐2024)

Mushtaq Ahmad, Basit Ali, Muhammad Ilyas, Shah Hamdani, Aiman Sher and Muhammad Yasir, IN: MAK Journal of Engineering and Applied Sciences, doi: 10.36478/makjeas.2025.18.23

This study discusses the availability of biomass resources, current policy and institutional landscape, technological readiness of BECCS and barriers and opportunities of BECCS implementation in Pakistan to explore the potential of BECCS. The case study measures how far Pakistan can utilise BECCS in the specified time frame. In this thesis, the focus on the discourse around sustainable energy transition in developing countries is applied through an analysis of Pakistan’s energy and environmental strategies through the last decade. Second, it aims to provide policymakers (and other stakeholders within industry and researchers that wish to use BECCS in national context for climate and energy policies and planning).

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Monteiro et al. (2025): Degrees of reversibility of ocean deoxygenation in an atmospheric carbon dioxide removal scenario

Estela A. Monteiro, David Peter Keller, James Christian, Jasmin G. John, Michio Kawamiya, Roland Séférian, Jerry Tjiputra, Andrew J. Wiltshire and Andreas Oschlies, IN: Environmental Research Letters, https://doi.org/10.1088/1748-9326/ade900

To reduce the carbon burden in the atmosphere in the future and thereby mitigate anthropogenic climate change, carbon dioxide removal (CDR) techniques have been increasingly studied and tested. However, information on the impact of CDR on oceanic oxygen is still scarce. In the current study the authors explore dissolved oxygen responses from an idealized CDR implementation, with atmospheric CO₂ ramp-up and ramp-down simulations following the Carbon Dioxide Removal Model Intercomparison Project (CDRMIP) protocol.

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Lin et al. (2025): Interactive effects of warming and drought on soil organic carbon sequestration and methane uptake in straw and biochar amended soils: Mechanisms and global implications

Jitong Lin, Guopeng Liang, Marcela Hernández, Zhiyu Xu, Yinghao Xue, Renhua Sun, Yuanfeng Sun, Lulu Dai, Yanhong Lou, Haojie Feng, Hui Wang, Quangang Yang, Hongjie Di, Hong Pan, Yuping Zhuge, IN: Chemical Engineering Journal, https://doi.org/10.1016/j.cej.2025.164817

The interactive effects of warming and drought on soil carbon-methane feedback in straw- versus biochar-amended agricultural systems need more comprehensive quantification, despite their critical implications for climate-smart soil management. By integrating controlled incubation experiments with a global meta-analysis (105 observations), the authors revealed that drought suppressed CH₄ uptake by 58.9% in carbon-amended soils through synergistic depletion of methanotrophic functional capacity (pmoA gene abundance) and microbial biomass carbon, while attenuating thermal sensitivity of methane uptake.

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