CO2-removal News

Peer-reviewed Publications

Price (2026): Losing out in Land-Based Greenhouse Gas Removal – A critical justice perspective on biochar

Catherine Price, IN: Exchanges: The Interdisciplinary Research Journal, https://doi.org/10.31273/eirj.v13i2.1892

Biochar is an emergent technology that is currently being investigated for its greenhouse gas removal potential at scale. This provides an ideal opportunity to investigate the potential injustices that may arise with biochar production and deployment so that these can be addressed. The author draws from original data collected in 2022-consisting of 37 semi-structured interviews with mostly UK-based stakeholders who have an interest or potential interest in biochar-supplemented with a document analysis. The paper uses the ‘multioptic vision’ model of who, what, and how to explore the potential injustices of biochar production and deployment.

LINK

#
Peer-reviewed Publications

Lee et al. (2026): Life cycle greenhouse gas reduction in bioenergy with carbon capture and storage processes for green hydrogen production

Ha Eun Lee, Jester Lih Jie Ling and See Hoon Lee, IN: Bioresource Technology, https://doi.org/10.1016/j.biortech.2026.134906

As the transition to a net-zero economy accelerates, bioenergy with carbon capture and storage (BECCS) has emerged as a critical negative emission technology. Nevertheless, the environmental viability of these systems is frequently uncertain due to the variety of operational configurations and carbon accounting frameworks in existence. The present study evaluates the environmental impacts of hydrogen production using BECCS under two energy-supply configurations: grid-connected and on-site self-sufficient scenarios.

LINK

#
Peer-reviewed Publications

Gately et al. (2026): Abrupt alkalinization alters microbial diversity and promotes the proliferation of marine parasites in coastal microcosm experiments

James A Gately, Sylvia M Kim, Zoe S Welch, Joaquín Martínez Martínez, Dylan Catlett, Benjamin Jin, Madeline Manzagol, Angela Larson, Mark A Brzezinski and Maria D Iglesias-Rodriguez, IN: ICES Journal of Marine Science, https://doi.org/10.1093/icesjms/fsag063

Mitigation of anthropogenic climate interference will likely require the removal of legacy atmospheric carbon dioxide (CO₂). Ocean alkalinity enhancement (OAE) is an abiotic marine carbon dioxide removal approach that accelerates the natural Earth process of rock weathering, but its effects on marine ecosystems remain uncertain. Here, the authors used outdoor microcosm experiments to investigate the effects of abrupt limestone-inspired and NaOH alkalinity additions of ∼750 μmol kg−1, reflecting model-predicted OAE scenarios that produce severe localized impacts (e.g. large variations in pH and Ω). They assess the response of seasonal marine microbial communities (phytoplankton, bacteria) and viruses from the Santa Barbara Channel, analyzed by high-throughput amplicon sequencing and flow cytometry.

LINK

#
Peer-reviewed Publications

Duret et al. (2026): Slaking quicklime with seawater for open-ocean alkalinity enhancement: Technical feasibility and cost implications

Manon Tiphaine Duret, Connor Clark and Kenton Heidel, IN: Frontiers in Climate, https://doi.org/10.3389/fclim.2026.1824086

Scalable carbon dioxide removal (CDR) solutions, such as ocean alkalinity enhancement (OAE), are necessary to mitigate climate change. One OAE approach is open-ocean liming, consisting in distributing hydrated lime (Ca(OH)₂) to increase seawater alkalinity and thereby long-term carbon storage in the ocean. Large-scale deployment would require transporting and distributing substantial quantities of Ca(OH)₂, making logistics a non-negligible component of total implementation costs. Most OAE studies to date assume the transport of Ca(OH)₂ rather than quicklime (CaO). However, CaO is denser, contains ~20% more alkalinity per unit mass, and has superior bulk handling properties compared to Ca(OH)₂. If technically feasible, transporting CaO and slaking it onboard using seawater could therefore reduce logistics costs. Here, the authors experimentally assess the feasibility of slaking CaO with artificial seawater. Slaking efficiencies and kinetics were comparable between seawater and deionized water, with CaO reactivity explaining more variance than solution composition. Seawater slaking produced secondary minerals, including likely brucite (~5 wt% of slurry) and gypsum (~0.3 wt%), but their formation is unlikely to reduce OAE efficiency under recommended alkalinity distribution practices. The authors also developed a simple transport cost model to compare land-slaked Ca(OH)₂ transport vs. transport and onboard slaking of CaO.

LINK

#
Peer-reviewed Publications

Agarwal et al. (2026): Direct Air Capture (DAC) Technologies and Subsurface Integration: A Comprehensive Technical Review

Akshit Agarwal, Yousef Al-Enizi and Cenk Temizel, IN: Offshore Technology Conference, https://doi.org/10.2118/232545-MS

Direct air capture (DAC) is one of the most promising negative emissions technologies (NETs), and is considered a key enabler to meet global climate mitigation goals and facilitate the transition to a low-carbon economy. Therefore, this review aims to provide an overview of the present state-of-the-art concerning DAC technologies, sorbent materials, energy systems, and subsurface storage techniques for long-term CO₂ sequestration. The DAC technologies can be classified into two main types, namely solid-sorbent based DAC and liquid- solvent based DAC systems. These two DAC technologies are compared and evaluated based on their technical features and performance parameters, and the challenges that arise during the application of these technologies are discussed. Additionally, this review focuses on the subsurface storage of captured CO₂ in deep saline aquifers, analyzing the processes of CO₂ transport and trapping, and discussing monitoring strategies and technologies. Energy consumption is considered the major cost factor of DAC technologies; therefore, this review examines possible ways to improve energy efficiency and integrate renewable energy sources.Furthermore, techno-economic evaluations show that capture costs of DAC technologies range from $200 to $600/ton CO₂, but costs may decrease by a factor of less than three due to the development and scale-up of new technologies. As part of practical applications, synergies between DAC technologies and enhanced oil recovery (EOR) processes in oil fields and the reuse of abandoned oil and gas reservoirs will be examined.

LINK

#
Peer-reviewed Publications

Wu et al. (2026): Forest carbon protocols underestimate climate-driven carbon loss risks

Chao Wu, Grayson Badgley, Michael L. Goulden, James T. Randerson, Anna T. Trugman, Jonathan A. Wang, Linqing Yang, Nezha Acil, Susan C. Cook-Patton, Danny Cullenward, Steven J. Davis, Christopher A. Williams and William R. L. Anderegg, IN: Nature, https://doi.org/10.1038/s41586-026-10571-y

Although the reduction of fossil fuel emissions remains of the utmost importance to mitigate climate change, maintaining and enhancing carbon sinks in forests have been widely promoted as nature-based climate solutions1,2,3,4. However, disturbances that could result in losses of forest carbon stocks are poorly accounted for when estimating the potential role of forests in climate mitigation5,6,7. This makes it difficult to appropriately size ‘buffer pools’: a mechanism designed to compensate for unintended carbon losses in carbon crediting projects8,9. Here the authors use forest inventory, satellite data, disturbance modelling and machine learning to map reversal (carbon loss) risk in the contiguous United States (CONUS) from natural disturbance.

LINK

#
Peer-reviewed Publications

Grosselindemann et al. (2026): The efficiency and ocean acidification mitigation potential of ocean alkalinity enhancement on multi-centennial timescales

Hendrik Grosselindemann, Friedrich A. Burger, and Thomas L. Frölicher, IN: Biogeosciences, https://doi.org/10.5194/bg-23-3299-2026

Carbon dioxide removal (CDR) strategies such as ocean alkalinity enhancement (OAE) are likely required in addition to rapid emissions reductions to limit global warming to well below 2 °C. However, the long-term efficiency of OAE and its potential to mitigate climate change and ocean acidification remain uncertain. Here, the authors investigate efficiencies, climate and ocean acidification responses of idealized OAE using a fully coupled, emission-driven Earth system model across three global warming stabilization scenarios (1.5, 2, and 3 °C) spanning 1861–2500. OAE is implemented as a continuous global surface alkalinity addition of 0.14 Pmol yr−1 following the CDRMIP protocol from 2026 onward.

LINK

#
Peer-reviewed Publications

Rombouts et al. (2026): Interactions between silicate weathering and ectomycorrhiza in severely acidified forests

Thomas Rombouts, Robrecht Van Der Bauwhede, Matteo Campioli, Håkan Wallander, Judith Sitters and Erik Verbruggen, IN: Communications Earth & Environment, https://doi.org/10.1038/s43247-026-03592-y

Soil acidification driven by anthropogenic nitrogen (N) deposition is a growing global threat to forest health. Aside from direct nutrient-related effects, as forest soils acidify, severe reductions in ectomycorrhizal (EcM) fungi abundance and diversity follow. This is worrisome, as EcM fungi are essential for tree nutrient acquisition and are important catalysts of mineral weathering and soil formation. Conventional remediation techniques such as dolomite liming often increase buffering too rapidly, leading to disturbed EcM fungal communities. Enhanced silicate weathering (ESW), the application of finely ground rock dust, has emerged as a more gradual, slow-release antacid. However, interactions and feedback processes between ESW and EcM remain poorly understood. ESW may improve EcM conditions, with outcomes depending on fungal community composition and mineralogy of the applied rock dust. Because EcM also accelerates mineral weathering, the authors postulate a positive feedback between ESW, EcM recovery and silicate dissolution. This synergy could restore nutrient cycling and tree vitality, while stabilising soil organic carbon (SOC) through complexation onto secondary minerals.

LINK

#
Peer-reviewed Publications

Cajada et al. (2026): Reversal of the warm Arctic -cold Eurasia intraseasonal coupling by CO₂ removal

M. Inês Cajada, Seok-Woo Son, Ye-Jun Jun, Shih-Yu Simon Wang, Jin-Ho Yoon and Seung-Ki Min, IN: Environmental Research Letters, https://doi.org/10.1088/1748-9326/ae6dd7

Midlatitude winter climate variability arises partly from its interactions with Arctic climate variability. A prominent example is the intraseasonal coupling between warm temperature anomalies over the Barents–Kara Seas and cold anomalies over central Eurasia, commonly referred to as the Warm Arctic–Cold Eurasia (WACE) relationship. Numerous studies have examined how this coupling may weaken under continued greenhouse gas warming. Yet, it remains unclear whether the WACE response to CO₂ warming reflects an irreversible change in atmospheric circulation or a reversible response to altered background conditions. In this study, the reversibility of the WACE relationship is investigated using a large-ensemble CO₂ ramp-up and ramp-down experiment. The WACE relationship is projected to weaken under increasing CO₂ concentrations.

LINK

#
Peer-reviewed Publications

Su et al. (2026): Feasible net carbon sink outcomes of China terrestrial ecosystem under economic and ecosystem service constraints

Boru Su, Moucheng Liu and Tianxiang Hao, IN: Environmental Impact Assessment Review, https://doi.org/10.1016/j.eiar.2026.108506

Ecosystem management (EM) is a key pathway for strengthening terrestrial carbon sinks in China, and net carbon sink effects depend on the feasibility of planned measures under economic cost and ecosystem service (ES) demand constraints. This study assessed the potential net carbon sink (CS) under full EM implementation, feasible CS1 under joint constraints, and the resulting CS limitation during 2020–2060 by integrating a CS–ES–economic benefits (EB) linkage framework and an integrated assessment model.

LINK

#