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        <title>Frontiers in Climate | Carbon Dioxide Removal section | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/climate/sections/carbon-dioxide-removal</link>
        <description>RSS Feed for Carbon Dioxide Removal section in the Frontiers in Climate journal | New and Recent Articles</description>
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        <pubDate>2026-05-13T05:08:58.465+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2026.1834276</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2026.1834276</link>
        <title><![CDATA[Potential and challenges for CDR in the European pulp and paper sector]]></title>
        <pubdate>2026-05-11T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Kristin Jordal</author><author>Rahul Anantharaman</author><author>Michaël Becidan</author><author>Simon Harvey</author><author>Rubén M. Montañés</author><author>Elin Svensson</author><author>Ugo Sirtori</author><author>Chiara Spampinato</author><author>Conny Johansson</author>
        <description><![CDATA[The European pulp and paper sector has an estimated potential for large-scale, permanent Carbon Dioxide Removal (CDR) of 50 Mtpa, through the implementation of CO2 capture and storage (CCS). CCS has been explored for this sector in literature, but results are limited compared to many other sectors and show substantial variability in costs and performance across mill types, operating conditions and locations. Several assessments highlight large kraft pulp mills in Northern Europe as among the most cost-effective opportunities. However, the characteristics of pulp mill black liquor recovery boiler flue gases raise concerns regarding the interaction with CO2 capture, due to elevated levels of alkali species, sulfur compounds, chlorides, trace metals and other constituents. Potential challenges include solvent degradation, foaming, fouling, corrosion and operational instability. Supported by results from pilot testing on two black liquor recovery boiler flue gases at a Swedish kraft pulp mill, this Perspective argues that more research is required in the public domain to understand the physico-chemical mechanisms involved in alkaline solvent CO2 capture from black liquor flue gases. Unleashing the CDR potential in the pulp and paper sector also requires a supportive regulatory framework and beneficial financial conditions, including buyers of CDR certificates on an megatonne scale. In view of the long investment cycles (up to 40 years) this Perspective calls for the development of scenarios for a stable, sustainable, climate-neutral economy well beyond 2050.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2026.1761760</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2026.1761760</link>
        <title><![CDATA[The state of macroalgae carbon dioxide removal: insights from a methodology development team]]></title>
        <pubdate>2026-05-07T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Donald E. Martocello III</author><author>Thomas Storwick</author><author>Carolyn Buchwald</author>
        <description><![CDATA[In the face of anthropogenic climate change, there is strong impetus to develop and implement durable carbon dioxide removal (CDR) technologies, alongside emissions reductions. CDR is an emerging private sector industry seeking to provide scientifically rigorous carbon offsets for entities unable to reduce carbon emissions below regulatory compliance or to support voluntary claims of carbon neutrality and reduction. Among nature-based CDR strategies, macroalgae (seaweed) cultivation is frequently cited as a promising and emerging pathway for ocean carbon storage in a variety of contexts. Despite widespread discussion in the literature and numerous papers that have modeled successful long-term storage by macroalgae cultivation, few field-scale studies exist and no accepted carbon crediting framework exists. Recently, a joint industry-academic partnership attempted to develop a rigorous ecologically-sound carbon credit methodology that aligned the goals of private sector and academic interests in macroalgae CDR. This perspective piece discusses the story of this endeavor, outlining the fundamental science necessary for developing a methodology, challenges that ultimately prevented the team’s completion, and insights into the necessary steps for advancing macroalgae CDR further. Rigorous and scalable macroalgae CDR will likely require public-led investment, greater reliance on affordable monitoring and measurements (e.g., satellite-based remote sensing), and rapid advances in computational processing likely facilitated by artificial intelligence. It is our hope that this perspective on our lessons learned can help inform and better steer the emerging CDR industry and provide a starting point for the next entity that seeks to pursue macroalgae-based CDR, including building on our most recent draft methodology.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2026.1805906</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2026.1805906</link>
        <title><![CDATA[Biotechnological innovations in the realm of carbon capture, storage and utilization]]></title>
        <pubdate>2026-04-22T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Fanny Machado Jofre</author><author>Carina Aline Prado</author><author>Vinícius Pereira Shibukawa</author><author>Maria Teresa Ferreira Ramos Raymundo</author><author>Thais Aline Prado Mendonça</author><author>Anuj Kumar Chandel</author>
        <description><![CDATA[The global energy transition increasingly relies on biotechnological innovation to meet climate targets. This study aims to evaluate the integration of carbon capture, storage, and utilization (CCUS) within a circular bioeconomy, bridging the gap between governance and technological implementation. While previous research often treats CCUS and bioenergy in isolation, this review provides a novel, integrated framework that connects climate governance (from COP26 to COP30) with specific carbon-negative pathways and advanced materials. The objectives are to assess the deployment of biofuels (SAF, biohydrogen), biochar, and bioplastics, specifically highlighting the role of Metal–Organic Frameworks (MOFs) in enhancing capture efficiency. Unique to this work is the inclusion of a multi-dimensional analysis incorporating Technological Readiness Levels (TRL), Life Cycle Assessment (LCA), and—crucially—Techno-Economic Analysis (TEA) to evaluate the impact on industrial scale-up. Main findings indicate that while biotechnological pathways are diversifying, the transition to commercial viability depends on aligning these advances with transparent financial mechanisms, such as blockchain-backed carbon credits. The outcomes serve as a strategic roadmap for industrial stakeholders to optimize investment in carbon-negative assets and provide policymakers with a scientific basis for standardizing sustainability metrics through the Global Biofuels Alliance (GBA), ultimately facilitating the scalability of commercially viable negative-emission solutions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2026.1732612</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2026.1732612</link>
        <title><![CDATA[Comparative study on the enhancing effects of CaSO4 and CaCl2 supplementation on red mud carbonation]]></title>
        <pubdate>2026-02-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yu Cheng</author><author>Shiying Yan</author><author>Lu Jin</author><author>Xu Wang</author><author>Ming Jia</author><author>Ping An</author><author>Binghui Sun</author>
        <description><![CDATA[Red mud (RM), a strongly alkaline solid waste generated during alumina production, can undergo carbonation with CO₂ for mineral sequestration. To investigate the promoting effect of external calcium sources on RM carbonation, desulfurization gypsum (CaSO4) and calcium chloride (CaCl2) were selected as supplements, and RM samples with/without these calcium sources were prepared. Experiments were conducted under various CO₂ concentrations (100, 15, 1%) and atmospheric conditions for both RM suspensions and solid-state RM (simulating open-air piles). The results showed that: (1) With increasing CO₂ concentration, the time for RM suspensions to reach pH equilibrium shortened (30 min for 100% CO₂ vs. 15 h for 1%), and the equilibrium pH decreased (to 6.8 for 100% CO₂ vs. 8.3 for 1%); (2) Under atmospheric conditions, the pH of RM suspensions supplemented with CaSO4 and CaCl2 decreased to 8.6 and 8.0, respectively, with CaCO3 characteristic peak intensity increasing compared to pure RM; (3) For solid RM, the two calcium sources lowered the minimum pH to 8.8 (CaSO4) and 8.4 (CaCl2), ultimately stabilizing around 9.0, whereas pure RM remained at 10.1. The CO₂ sequestration capacities reached 45.3 g/kg and 47.2 g/kg, respectively, while forming a porous CaCO3 coating on the RM particles. The calcium sources significantly enhanced the stability and durability of the carbonation reaction, providing a scientific basis for long-term CO₂ sequestration.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2026.1744296</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2026.1744296</link>
        <title><![CDATA[Beyond ‘doing both’—framing carbon removal carefully]]></title>
        <pubdate>2026-01-29T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Nils Markusson</author><author>Juanita von Rothkirch</author><author>Kate Dooley</author>
        <description><![CDATA[There is a common framing in communications about carbon dioxide removal (CDR) which amounts to saying ‘we need to do both’ CDR and emissions reductions, but without explaining further what this means or how to achieve it. This leaves the impression that such framing is empty and performative, doing little to counteract the risk of mitigation deterrence, i.e., that the pursuit of CDR undermines and delays emission reductions, which the framing is meant to address. This article substantiates and illustrates this claim, and develops recommendations for how to frame CDR more carefully. Such careful framing crucially involves indicating the relatively minor role CDR can play compared to emissions reductions on the path to net zero. Finally, we reflect on the barriers to and importance of these recommendations being taken up.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1717924</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1717924</link>
        <title><![CDATA[A novel methodology to characterize the potential impacts of electrochemical ocean alkalinity enhancement on juvenile coho salmon (Oncorhynchus kisutch)]]></title>
        <pubdate>2026-01-27T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Mallory C. Ringham</author><author>Matthew P. Galaska</author><author>Michelle Knowlen</author><author>Jeremy Loretz</author><author>Tyson Minck</author><author>Todd Pelman</author><author>Nathan Soccorsy</author><author>Kyla Westphal</author><author>Jay Word</author>
        <description><![CDATA[Ocean alkalinity enhancement (OAE) includes a branch of marine carbon dioxide removal (mCDR) methods that add alkalinity to the surface ocean, leveraging the ocean's vast natural ability to capture and store atmospheric CO2. The impact of OAE on marine ecosystems will depend on the type and delivery of alkaline feedstock to the ocean, which typically results in elevated pH and total alkalinity and decreased pCO2 in the near-field of an OAE application. These signals will decrease in space and time away from the point of alkaline addition until are no longer measurable against the background of natural variability in the marine environment. It is important to evaluate potential impacts of OAE on marine ecosystems within the context of realistic OAE deployments. This study highlights the use of an effluent dilution model to describe the measurable extent of the release of electrochemically-generated aqueous alkalinity from Ebb Carbon's research pilot in Port Angeles, WA. We describe a novel laboratory method to simulate the potential exposure of juvenile coho salmon to the pilot's alkaline discharge, representing exposure to OAE field conditions as salmon swim through the pilot's mixing zone. Salmon were exposed to an electrochemically generated alkalinity-enhanced seawater solution pulsed into a test chamber at a dilution factor predicted approximately 3 m from the alkaline outfall. The alkalinity-enhanced seawater was held for 30 s, 1 min, and 5 mins, then was slowly flushed with ambient seawater. The alkaline solution, initially at pHNBS 10.0, was released into seawater at pHNBS 7.6, resulting in peak pH of the mixed solution of 8.04-8.09, with an increase in total alkalinity of ~60 μmol/kg. The results of the study indicated no impact on juvenile coho salmon behavior, survival, or physical effects on gills, eyes, or external body tissues, relative to control tests. The experimental design, developed for performance by a commercial toxicology laboratory and supported by standard mixing analyses, allows for rapid repetition with species of interest near OAE deployments.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1710187</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1710187</link>
        <title><![CDATA[A robust deep learning framework for predicting carbon dioxide-water alternating gas injection performance and optimization]]></title>
        <pubdate>2026-01-15T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Shahab Ud Din</author><author>Liang Xue</author><author>Guo Dongdong</author><author>Tamer Abu-Alam</author><author>Muhsan Ehsan</author><author>Anas A. Ahmed</author>
        <description><![CDATA[Carbon dioxide (CO2) emissions pose a major environmental concern, and various methods are used for CO2 sequestration. CO2-water activating gas (CO2-WAG) injection is a technique used to increase production of oil and sequester CO2 in subsurface formations. However, the performance of the CO2-WAG project depends on various parameters, such as injection rates, cycle size, and ratio, that traditionally require numerous computationally expensive simulations. The study introduces a robust machine learning workflow for CO2-WAG performance prediction and optimization by using a model calibrated using Bell Creek formation properties. Machine learning models are based on algorithms like extreme gradient boosting (XGBoost), linear regression (LR), random forest (RF), k-nearest neighbor (KNN), support vector regression (SVR), artificial neural network (ANN), convolutional neural network (CNN), and hybrid models such as ANN and CNN coupled with XGBoost (ANN-XGBoost, and CNN-XGBoost) to predict CO2-WAG performance. A dataset of 2,400 samples was generated using the CMG-GEM numerical simulator, incorporating seven input parameters (e.g., injection rate, CO2-WAG cycle size, and WAG ratio) and three output parameters, with 80% of the dataset allocated for training and 20% for validation and testing. Among the proposed models, the hybrid model ANN-XGBoost demonstrated superior performance, accurately predicting total oil production, CO2 storage, and efficiency, with high R2 scores of 0.99159, 0.97515, and 0.98706, and corresponding lower RMSE values of 2.8 × 10−2, 1.5 × 10−1, and 2.4 × 10−2. Coupling the proxy with particle swarm optimization (PSO) yielded 12.8% increase in cumulative oil production and 11% increase in CO2 storage. Furthermore, in terms of speed, the projected workflow requires less minutes to complete predictions and optimization, while traditional numerical simulators require 4–5 min per scenario. These findings validates the robustness and computational efficiency of the proposed machine learning workflow for predicting CO2-WAG performance and optimization.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1657058</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1657058</link>
        <title><![CDATA[Evidence for carbon dioxide removal via enhanced rock weathering with steel slag, though not basalt, in a midwestern U.S. field trial]]></title>
        <pubdate>2026-01-13T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Daniel P. Maxbauer</author><author>Ella Milliken</author><author>Jahmaine Renzo Yambing</author><author>Emma Watson</author><author>Rachel B. Gregg</author><author>Liza Swanson</author><author>Jaeeun Sohng</author><author>Noah W. Sokol</author><author>Noah J. Planavsky</author>
        <description><![CDATA[Enhanced weathering is an emergent pathway for permanent atmospheric carbon dioxide removal (CDR). However, despite a dramatic increase in academic and commercial research, there remain relatively few published examples of field evidence demonstrating the effectiveness of enhanced weathering. Here, we present results from a three-year field trial that evaluated steel slag and crushed basalt applied as amendments in a conventional agricultural system in the Midwestern United States. Steel slag applied to initially acidic soil increased porewater pH and alkalinity and increased soil pH and Ca-saturation. Together, changes in porewater chemistry and soil properties provide strong evidence for steel slag weathering and CDR. However, steel slag applied to soils with a neutral initial pH did not generate significant changes in soil or porewater chemistry. In addition, coarse-grained crushed basalt did not generate significant change in any of the soils. Strong acid effects were apparent in all 3 years of monitoring soil porewater chemistry. Overall, our results demonstrate clear evidence of CDR from applying steel slag amendments to acidic cropland soils while also highlighting the difficulty of greenhouse gas reduction accounting from enhanced weathering and the variable outcomes that can occur depending on feedstock and soil type.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1688361</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1688361</link>
        <title><![CDATA[An uncertainty-aware framework for solid-phase measurement and verification of enhanced weathering]]></title>
        <pubdate>2026-01-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Brian Rogers</author><author>Kate Maher</author>
        <description><![CDATA[Reliable verification of enhanced weathering as a carbon dioxide removal strategy requires accurate quantification of feedstock dissolution in amended soils. However, spatial heterogeneity introduces significant uncertainty, particularly in sampling designs that rely on sparse or repeated measurements at fixed locations. Here, we develop a probabilistic framework to evaluate how spatial uncertainty in solid-phase geochemical measurements influences the precision of feedstock dissolution estimates derived from an element-element mixing model. We first quantify how variance in soil compositions affects errors in modeled feedstock dissolution and apply distance-based sensitivity analysis to identify the measurement variance thresholds required to achieve desired uncertainty levels. Next, we simulate spatially heterogeneous soil conditions and various composite sampling configurations to identify the optimal sampling strategy likely to meet specified uncertainty criteria. Our findings underscore the necessity of accurately estimating field-scale variance in baseline soil concentrations prior to developing sampling plans. Analysis of data from existing high-density soil sampling campaigns indicates that geochemical variance is likely too high for element-element mixing models to serve as effective near-term constraints on feedstock dissolution. The framework presented here can be further extended to other solid- and multi-phase measurement models for enhanced weathering verification.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1665329</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1665329</link>
        <title><![CDATA[Ocean alkalinity enhancement in an estuary]]></title>
        <pubdate>2026-01-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Minna Ho</author><author>Jeroen Molemaker</author><author>Pierre Damien</author><author>Matthew C. Long</author><author>Daniele Bianchi</author><author>James C. McWilliams</author>
        <description><![CDATA[A high-resolution numerical ocean model is used to assess ocean alkalinity enhancement (OAE) in the San Francisco Bay (SFB) estuary. A novel tracer-based approach is introduced to simulate alkalinity release and the subsequent CO2 ingassing. The model is run for 6 days and accurately reproduces observational data of currents, density, and tides. Estuarine dynamics induce mixing, advect buoyant water out of the Bay, and transport the added alkalinity from deep in the estuary to the surface of the open ocean. Over 80% of the tracer remains in the upper 15 m throughout the simulation. The estimated air-sea equilibration rate of the added alkalinity is approximately 2% per day. Alkalinity exported to the open ocean plays a disproportionately large role in increasing the CO2 ingassing rate compared to that in the estuary. This rate is relatively fast compared to open-ocean OAE studies due to the San Francisco Bay buoyant plume, which confines the released alkalinity to the surface mixed layer. While estuaries offer many benefits for OAE releases, further studies are needed to quantify their biogeochemical and ecosystem impacts.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1658453</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1658453</link>
        <title><![CDATA[Responsible research and innovation of carbon removal: strategies for field trials]]></title>
        <pubdate>2025-12-10T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Laurie Waller</author><author>Emily Cox</author><author>Amy Binner</author><author>Tatiana Cantillo Garcia</author><author>Rosie Everett</author><author>Karen Henwood</author><author>Julie Ingram</author><author>Carol Morris</author><author>Kate O'Sullivan</author><author>Nick Pidgeon</author><author>Catherine Price</author><author>Mark Reed</author><author>Alessandro Silvestri</author><author>Rob Bellamy</author>
        <description><![CDATA[Demonstrating methods for removing carbon dioxide from the atmosphere is now a focus of research and development programmes designed to support decision making about future technology deployment. In this perspective piece, we outline some of the approaches to responsible research and innovation (RRI) being put to work in a United Kingdom-based programme organising field trials of various carbon removal methods. Unlike the disruptive technologies that predominate in RRI scholarship, many land-based methods for carbon removal have already been deployed, in some cases over many decades, with governance closely linked with longstanding fields of research and practice. We highlight why responsible innovation frameworks that developed in the context of geoengineering controversies may be only partially-suited to field trials of land-based carbon removal methods. We suggest that field trials of carbon removal methods are not simply evidentiary procedures but also strategic sites within an emerging innovation regime where RRI approaches can be both implemented and critically tested.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1649723</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1649723</link>
        <title><![CDATA[Assessing the limitations of commercial sensors and models for supporting marine carbon dioxide removal monitoring: a case study]]></title>
        <pubdate>2025-11-03T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Tristen Stewart</author><author>Peter Regier</author><author>Kyle E. Hinson</author><author>Carolina Torres Sanchez</author><author>Quinn Mackay</author><author>Nicholas D. Ward</author><author>Jessica N. Cross</author>
        <description><![CDATA[Several unknowns remain surrounding marine Carbon Dioxide Removal (mCDR) monitoring, reporting, and verification (MRV) practices and capabilities. Current in-situ sensor technology is limited (primarily pH and pCO2), requiring calculations and assumptions to estimate changes in carbonate chemistry parameters, including total alkalinity (TA). Considering that cost, energy consumption, and accuracy of commercial sensors can vary by orders of magnitude, understanding how well existing sensors perform in an mCDR context is important for this emerging community. Likewise, documenting sensor limitations and how relatively simple models can optimize sensor deployments will improve MRV efforts and support protocol development. Here we (1) compare performance a variety of commercially available sensors in a blind mesocosm experiment simulating ocean alkalinity enhancement (OAE), and how sensor performance impacted carbonate chemistry estimates; (2) evaluate if sensors can distinguish the OAE signal from natural variability during a small scale OAE field test in Sequim Bay, WA, USA, and (3) use an idealized ocean biogeochemistry model to explore optimal sensor network design based on (1) and (2). Our mesocosm results indicate that correctly constraining pH uncertainty will be critical for accurate TA estimates with current sensor technology compared to the less impactful variation caused by uncertainty in pCO2 (pH data that are presented throughout are reported on the total scale (pHT) unless otherwise noted). Our pilot field test demonstrated that sensors were capable of distinguishing mCDR signatures from natural variability under optimal real-world conditions. Idealized modeling simulations of the field test showed that a range of sparse and dense (3 to 100) sensors sampling areas of detectable increases will underestimate the net change in surface pH by at least 35–55%, at both realistic and highly elevated alkalinity input levels. We also highlight the limitations of current sensing technology for MRV, and the importance of ocean biogeochemistry models as critical tools for predicting when and where mCDR signals will be detectable using available sensors. Overall, our findings suggest that commercially available pCO2 sensors and some pH sensors will form an important backbone for mCDR MRV tasks, though complete MRV characterization will require these data to be used in combination with other tools.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1685187</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1685187</link>
        <title><![CDATA[Permanent storage of carbon dioxide in mafic rock formations: exploring Sweden’s potential]]></title>
        <pubdate>2025-10-31T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Emelie Crafoord</author><author>Christina Wanhainen</author><author>Glenn Bark</author>
        <description><![CDATA[Mineral carbonation in reactive bedrock offers a rapid and permanent method for carbon dioxide (CO2) sequestration, converting CO2 into stable mineral phases within a geologically short timeframe. This study presents the first-ever systematic assessment of onshore CO2 mineral storage potential in Sweden, based on fieldwork, sampling, and mineralogical and geochemical analyses conducted at 23 localities. While this theoretical assessment cannot resolve uncertainties related to reactivity, dissolution capacity, and sequestration efficiency, it provides a critical foundation for identifying potentially favorable storage reservoirs. The findings highlight the Örnsköldsvik and Sundsvall areas in central Sweden, hosting a gabbro-anorthosite complex together with a set of dolerites, as the more suitable lithologies for onshore CO2 storage. These rocks are distinguished by their high content of reactive minerals—including olivine, Ca-rich plagioclase, and clinopyroxene—and low content of alteration phases. In the few locations where secondary phases such as serpentine and chlorite were observed, they were confined to grain boundaries and microfractures and did not appear to be pervasive throughout the rock. This preservation of primary mineralogy and textures supports the interpretation that these two lithologies are among the most suitable for CO2 mineral storage within the studied rock formations, under geochemical and thermal conditions favorable for mineral carbonation. This work provides the necessary foundation for future and ongoing experimental validation of reactivity and permeability and detailed site-specific investigations.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1616362</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1616362</link>
        <title><![CDATA[Using magnesium hydroxide for ocean alkalinity enhancement: elucidating the role of formation conditions on material properties and dissolution kinetics]]></title>
        <pubdate>2025-10-24T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Cody Shaw</author><author>Mallory C. Ringham</author><author>Brendan R. Carter</author><author>Michael D. Tyka</author><author>Matthew D. Eisaman</author>
        <description><![CDATA[Mg(OH)2 holds potential as an alkalinity source for Ocean Alkalinity Enhancement (OAE). In this study, Mg(OH)2 was produced via precipitation from the alkalinity exchange of NaOH addition into brine. Mineralogy characterization (XRD, EDS, SEM) and dissolution kinetics (total alkalinity release rates) were used to investigate the adoption of seawater-precipitated Mg(OH)2 for OAE and compared to industrial sources. XRD revealed industrial sources contained a higher degree of crystallinity of 0.83–0.85 compared to 0.16–0.33 for seawater-precipitated paste. Mg(OH)2 at a higher degree of crystallinity (>80%) had significantly slower dissolution rates than Mg(OH)2 with a lower degree of crystallinity (<20%). A strong inverse relation between degree of crystallinity and dissolution rate was found for both seawater-precipitated and industrial sourced Mg(OH)2. Despite similar elemental composition to industrial sources, seawater-precipitated Mg(OH)2 exhibited lower crystallinity resulting in faster and more complete dissolution, suggesting a potential advantage over other alkalinity sources. Its seemingly tunable dissolution kinetics due to crystallinity provides an opportunity to optimize the material for OAE and carbon dioxide removal efficiency.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1640617</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1640617</link>
        <title><![CDATA[Regional ocean biogeochemical modeling challenges for predicting the effectiveness of marine carbon dioxide removal]]></title>
        <pubdate>2025-10-08T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Nicholas D. Ward</author><author>Kyle E. Hinson</author><author>Rémi Pagès</author><author>Jessica N. Cross</author><author>Marjorie A. M. Friedrichs</author><author>Claudine Hauri</author><author>Parker MacCready</author><author>Chinmayee V. Subban</author><author>Jilian Xiong</author><author>Pierre St-Laurent</author><author>Zhaoqing Yang</author>
        <description><![CDATA[Effectively scaling diverse marine carbon dioxide removal (mCDR) technologies from pilot-scale demonstrations to industrial-scale deployments requires a quantitative understanding of how much additional carbon a given deployment will sequester compared to a scenario with no mCDR intervention and the long-term durability of the stored carbon. Given the high environmental variability and vast size of the ocean carbon pool, observations alone cannot resolve the amount, rate, and fate of mCDR-associated carbon sequestration. Likewise, when conducting an mCDR deployment it is impossible to observe a counterfactual scenario with no mCDR deployment performed. For this reason, ocean biogeochemical models are expected to play a key role in advancing mCDR deployments by informing observational requirements, defining uncertainty envelopes, and ultimately verifying durable carbon sequestration. However, current models, which are designed to capture basic ocean processes, have limitations when being used for this new application—simulating perturbations to the ocean system ranging in scale. Here, we describe our perspective on the most critical ocean biogeochemistry model process representations that need to be refined or added to accurately simulate the impact of a subset of mCDR approaches on carbon uptake and ocean biogeochemistry.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1627432</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1627432</link>
        <title><![CDATA[What regional agricultural actors want to know about carbon dioxide removal in Northern Germany]]></title>
        <pubdate>2025-09-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Juliane El Zohbi</author><author>Lea Griesing</author><author>Gabriele Torma</author><author>Diana Rechid</author>
        <description><![CDATA[Many countries, including Germany, have made their climate targets dependent on the implementation of methods for removing carbon dioxide from the atmosphere. Actors in the agricultural sector can contribute to this implementation. However, there is a knowledge gap regarding carbon dioxide removal (CDR) among agricultural actors. In this study, we interviewed 34 agricultural actors at the micro, meso, and macro levels to identify the factors hindering the implementation of CDR practices, namely soil carbon sequestration, biochar, and agroforestry. We identified 22 information needs related to the dimensions of Climate change mitigation, Technological conditions, Environmental impacts, Economics, Policy & government, and Social aspects from the interviews. Farmers expressed more information needs compared with representatives from farming associations or local and regional administrations. Across all interviews, recommendations for action were most requested, with a high preference for information in digital online formats. Our findings provide a checklist for future research in the form of co-developed actionable knowledge between researchers and agricultural actors to increase the knowledge but especially the use of agricultural practices to remove carbon dioxide from the atmosphere.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1652680</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1652680</link>
        <title><![CDATA[Determining the net influence of biological processes on aqueous hydroxide-based ocean alkalinity enhancement: a mesocosm approach]]></title>
        <pubdate>2025-09-15T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Derek Fucich</author><author>Heather J. Lynch</author><author>Cody Shaw</author><author>Matthew D. Eisaman</author><author>Mallory C. Ringham</author>
        <description><![CDATA[Ocean alkalinity enhancement (OAE) presents a promising means to leverage the ocean carbon sink to mitigate the effects of anthropogenic climate change. We report on a series of mesocosm experiments simulating electrodialysis-based OAE through the addition of aqueous sodium hydroxide to seawater in large tanks (~6,000 L) and small aquaria (~10 L) at Flax Pond Marine Laboratory, NY. In previous studies, the confounding effects of biological processes were controlled by imposing a sterilization treatment to seawater throughout each experiment. Here, we take the first steps in characterizing the influence of biological processes on OAE-based CO2 uptake through comparisons between sterilized and unsterilized mesocosms and aquaria. We combine our results with those of similar Flax Pond mesocosm experiments and develop a model to identify the most influential variables for determining the rate and magnitude of CO2 uptake. We found that the rate of CO2 uptake varies with changes in initial carbonate chemistry, the amount of alkalinity added, whether the mesocosm was sterilized, and the season in which the seawater was collected. Our model suggests that sterilized tanks did not differ in the amount of CO2 sequestered, but experienced a slower rate of equilibration relative to unsterilized tanks. These results indicate that laboratory mesocosm experiments could reasonably represent CO2 uptake in the field even with the complication of biological processes over the timeline of air-sea CO2 equilibration. This finding is valuable in supporting the measurement, reporting and verification of OAE, which must rely on a combination of laboratory data, near-field measurements, and modeling exercises.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1606574</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1606574</link>
        <title><![CDATA[Quantifying potential carbon dioxide removal via enhanced weathering using porewater from a field trial in Scotland]]></title>
        <pubdate>2025-09-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Amy L. McBride</author><author>Kirstine Skov</author><author>Peter Wade</author><author>Joey Betz</author><author>Amanda Stubbs</author><author>Tzara Bierowiec</author><author>Talal Albahri</author><author>Giulia Cazzagon</author><author>Chieh-Jhen Chen</author><author>Amy Frew</author><author>Matthew Healey</author><author>Ifeoma Idam</author><author>Lucy Jones</author><author>Mike E. Kelland</author><author>Jim Mann</author><author>David Manning</author><author>Callum Mitchell</author><author>Melissa J. Murphy</author><author>Anežka Radkova</author><author>Marta-Villa de toro Sanchez</author><author>Utku Solpuker</author><author>Yit Arn Teh</author><author>Rosalie Tostevin</author><author>Will Turner</author><author>Jez Wardman</author><author>Morven Wilkie</author><author>XinRan Liu</author>
        <description><![CDATA[Enhanced weathering (EW) is cited as a promising carbon dioxide removal (CDR) strategy, and is being rapidly commercialized. Rigorous monitoring, reporting and verification (MRV) are essential to ensure carbon claims are accurate and carbon credits are not mis-sold. MRV protocols incorporate multiple approaches, including soil and porewater sampling. This paper calculates potential CDR (pCDR) from porewater (direct pCDR), via an alkalinity estimation calculated from charge balance, and from soil samples (inferred pCDR), via the accumulation of exchangeable cations on soil exchange sites. These pCDR estimations are then compared to the maximum theoretical CDR potential. The data were collected from a 1.5 year field trial, situated in south-east Scotland. Crushed basalt was surface-applied to plots at rates of 0 (control), 23, 78 and 126 t ha−1. Application rates were increased relative to common agricultural spreading practices (78 and 126 t ha−1) to increase the chances of detecting a signal. To calculate direct pCDR from porewater, ion concentrations of porewater samples extracted from a depth of 5 and 10 cm were integrated with precipitation surplus to estimate the flux of cations leaching from each depth over c. 2 week periods, as water budgets allowed. Ordinary least squares model results identified a significant effect of treatment as an explanatory variable for potential CDR, both at 5 and 10 cm depth. Direct pCDR ranging from 0.33 to 0.53 tCO2 ha−1 after c. 1.5 years of weathering was calculated in the 5 cm depth treatment in the 78 and 126 t ha−1 application treatment relative to the control. The model prediction interval was overlapping between the control and the 23 t ha−1 treatment at 5 cm depth, as well as for all the treatments in the 10 cm treatments when evaluated relative to the control. Carbonate precipitation was also assessed, but remained below the detection limit (0.1 wt.% inorganic carbon). Inferred pCDR calculated from 30 cm-deep soil samples were not significant, possibly as a result of experimental design and sampling density. Overall, when direct pCDR is normalized to mass of rock applied and duration of weathering (e.g., mass-time-normalized-pCDR), the values fall within the mid-range of values published from other field studies.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1592454</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1592454</link>
        <title><![CDATA[Pyrogenic carbon and carbonating minerals for carbon capture and storage (PyMiCCS) part II: organic and inorganic carbon dioxide removal in an Oxisol]]></title>
        <pubdate>2025-08-25T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Maria-Elena Vorrath</author><author>Thorben Amann</author><author>Johannes Meyer zu Drewer</author><author>Nikolas Hagemann</author><author>Cierra Aldrich</author><author>Janine Börker</author><author>Maria Seedtke</author><author>Joscha N. Becker</author><author>Mathilde Hagens</author><author>Annette Eschenbach</author><author>Jens Hartmann</author>
        <description><![CDATA[Enhanced rock weathering (ERW) and pyrogenic carbon capture and storage (PyCCS, or “biochar carbon removal”) are two promising carbon dioxide removal (CDR) techniques that can contribute to soil restoration. These technologies can be combined by co-application of rock powder and biochar or by co-pyrolysis of rock powder with biomass to produce rock-enhanced (RE) biochar. In a 27-week laboratory experiment, we quantified the carbon (C) sink development of co-applications and RE-biochars produced by co-pyrolysis of basanite rock powder with either 50 or 90 wt% willow wood or 90 wt% wheat straw. Incubators featured two elevated soil pCO2 levels (0.012 and 0.062 atm, equivalent to about 1.2 and 6.2 Vol-% CO2) in a clay-rich, nutrient-poor Oxisol, with a simulated annual rainfall of 1,600 mm. Results showed strong initial fluxes of total alkalinity (TA), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and major cations (Mg2+, Ca2+, K+, Na+), which decreased over time. Notably, elevated pCO2 had minimal impact on the release of DOC but doubled the TA flux from ERW. An important observation was the impact of waterlogging on water fluxes in soil columns without biochar, which lowered the amount of leached cations from rock and biochar. We defined the carbon sink (C-Sink) to include all DIC of geogenic and biogenic origin, and pyrogenic carbon from biochar. Biogenic cations were not considered as contributing to additional CO2 sequestration. For a soil application equivalent to application of 12 t ha−1, the total net C-Sink ranged from −0.1 to 30.9 t CO2 ha−1 after 27 weeks under 1.2 Vol-% CO2. We were not able to determine a change in rock weathering rates from co-pyrolysis since biogenic and geogenic cations could not be distinguished. A 20-year forecast suggests net C-Sinks between 0.5 t and 28.7 t CO2 ha−1, driven by increased contributions from weathering, alongside a C-Sink loss of carbon due to biochar mineralization. While biochar alone generally produces a larger C-Sink, co-application with rock powder fosters soil remineralization and provides a higher permanence of the C-Sink. Additionally, biochar increases water-holding capacity, prevents waterlogging of soils and likely improves the retention of organic carbon in soils.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fclim.2025.1528951</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fclim.2025.1528951</link>
        <title><![CDATA[Removal of dissolved inorganic carbon from seawater for climate mitigation: potential marine ecosystem impacts]]></title>
        <pubdate>2025-07-31T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Guy Hooper</author><author>Helen S. Findlay</author><author>Thomas G. Bell</author><author>Rod W. Wilson</author><author>Paul R. Halloran</author>
        <description><![CDATA[Electrochemical technology can be used to remove inorganic carbon from seawater and facilitate the removal of carbon dioxide (CO2) from the atmosphere. Electrochemical ‘Direct Ocean Carbon Capture and Storage’ (DOCCS) is a marine carbon dioxide removal (mCDR) method that removes atmospheric CO2 by releasing low-carbon seawater into the surface ocean, where it re-equilibrates with the atmosphere and stores atmospheric CO2. At the point of release, DOCCS discharge has low concentrations of dissolved inorganic carbon (DIC) and high pH, potentially causing unintended marine environmental impacts; however, its chemistry moves progressively towards that of ambient seawater as it dilutes and re-equilibrates with the atmosphere. To date, there are no published studies that investigate the impact of DOCCS discharge on marine ecosystems. Research from relevant analogues, where biological responses to low-DIC and/or high-pH seawater are investigated, provides some insight into potential DOCCS impacts. Despite this, significant evidence gaps remain. These evidence gaps are discussed alongside DOCCS-specific recommendations for future environmental impact research. Understanding the potential risks/benefits to marine ecosystems from discharge of low-DIC and high-pH seawater is critical to: (i) support licensing applications; (ii) develop any necessary mitigating actions; (iii) determine the net benefit of mCDR approaches; and (iv) stimulate informed public discourse about the acceptability of such approaches.]]></description>
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