Schlagwort: enhanced weathering

Peer-reviewed Publications

Suhrhoff et al. (2025): Aggregated monitoring of enhanced weathering on agricultural lands – Preprint

Tim Jesper Suhrhoff, Anu Khan, Shuang Zhang, Beck J Woollen, Tom Reershemius, Mark A. Bradford, Alexander Polussa, Ella Milliken, Peter A. Raymond, Chris Reinhard, Noah Planavsky, IN: CDRXiv, https://doi.org/10.70212/cdrxiv.2025394.v1

Terrestrial enhanced weathering (EW) on agricultural land is a promising carbon dioxide removal (CDR) pathway with high potential to scale. Enhanced weathering also has the potential to provide significant agronomic co-benefits to farmers and producers. Today, most EW field trials are funded through the voluntary carbon market (VCM) with the purpose of generating carbon removal credits for corporate sustainability goals. As a result, monitoring, reporting, and verification (MRV) frameworks for EW are designed for attribution of tons of removal via weathering to individual fields. Here, the authors describe approaches for aggregation of weathering indicators across multiple fields using aqueous, solid, and gas phase measurements.

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Peer-reviewed Publications

Planavsky et al. (2025): Bridging time lags in durable carbon removal on working lands

Noah J. Planavsky, Beck J. Woollen, Ella Milliken, Mojtaba Fakhraee, David J. Beerling and Christopher T. Reinhard, IN: ESS Open Archive, https.://doi.org/ 10.22541/essoar.175855457.77763746/v1

Enhanced weathering and biochar application on working lands show promising signs of delivering durable carbon dioxide removal required to meet internationally agreed upon climate change mitigation goals. Although both technologies can scale comparatively quickly, their ability to offset radiative forcing from anthropogenic greenhouse gas emissions is delayed by time lags between deployment and realized carbon removal. Here, the authors suggest that coupling enhanced weathering and biochar with point-source methane emissions reductions provides a robust crediting framework for carbon credits that can continuously-and immediately-offset anthropogenic emissions.

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Peer-reviewed Publications

Nature – Beerling et al. (2025): Challenges and opportunities in scaling enhanced weathering for carbon dioxide removal

David J. Beerling, Christopher T. Reinhard, Rachael H. James, Anu Khan, Nick Pidgeon and Noah J. Planavsky, IN: Nature Reviews Earth & Environment, https://doi.org/10.1038/s43017-025-00713-7

Terrestrial enhanced weathering (EW) on agricultural lands is a proposed carbon dioxide removal (CDR) technology involving the amendment of soils with crushed base cation-rich rocks, such as basalt. Over a quarter of a billion dollars have been raised by commercial EW start-ups across the globe, accelerating the deployment of EW at scale. In this Review, the authors outline the scientific knowledge and policy requirements for scaling EW.

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Peer-reviewed Publications

McBride et al. (2025): Quantifying potential carbon dioxide removal via enhanced weathering using porewater from a field trial in Scotland

Amy L. McBride, Kirstine Skov, Peter Wade, Joey Betz, Amanda Stubbs, Tzara Bierowiec, et al., IN: Frontiers in Climate, https://doi.org/10.3389/fclim.2025.1606574

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.

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Peer-reviewed Publications

MacDonald et al. (2025): Atmospheric carbon dioxide mineralisation in anthropogenically-derived carbonate deposits

John MacDonald, Charlotte Slaymark, Amanda Stubbs and Marta Kalabová, IN: Swiss Digital Karst, https://doi.org/10.57035/journals/sdk.2025.e31.1929

Removing carbon dioxide from the atmosphere is important in minimising the impact of anthropogenically-induced climate change. Anthropogenic geomaterials, such as slag and cement, can be utilised in an engineered context for mineralising CO₂. However, such anthropogenic geomaterials, typically waste products, were usually deposited on the land surface and left to passively mineralise CO₂, resulting in the formation of anthropogenic carbonates. In this study, the authors document anthropogenic carbonates from a suite of locations across Scotland and Northern England, and use stable carbon and oxygen isotopes to show that they are formed from atmospheric CO₂.

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Peer-reviewed Publications

Kukla et al. (2025): Swapping carbonate for silicate in agricultural enhanced rock weathering

Tyler Kukla, Yoshiki Kanzaki, Freya Chay, Noah Planavsky, Chris Reinhard, IN: CDRXiv, https://doi.org/10.70212/cdrxiv.2025304.v1

Enhanced rock weathering with crushed silicates is often considered as an alternative to agricultural liming for soil pH management and carbon dioxide removal. But swapping carbonates for silicates does not guarantee better carbon removal outcomes. Carbonates weather rapidly, and recent work has found that they can remove more carbon than fast-reacting silicates in some environments. On the other hand, carbonate dissolution can mobilize fossil carbon and potentially lead to carbon emissions, depending on the spatial and temporal boundaries of the system. Here, the authors use a one-dimensional reactive transport model, SCEPTER, to analyze the conditions where carbonate weathering breaks even with basalt — a common silicate rock used in enhanced weathering — from an end-to-end carbon removal perspective.

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Peer-reviewed Publications

Tian et al. (2025): Stability of alkalinity in the land-ocean transition zone: a geochemical CDR perspective for the Elbe River, Germany

Mingyang Tian, Jens Hartmann, Niels Suitner, Thorben Amann, Stephan Kempe, Carl Lim and Charly A Moras, IN: Environmental Research Letters, https://doi.org/10.1088/1748-9326/adeeab

Carbon dioxide removal (CDR) strategies like enhanced weathering and river/ocean alkalinity enhancement have been suggested to increase alkalinity in rivers, coastal areas, and eventually oceans. The effectiveness and sustainability of these CDR approaches depend on the persistence of added alkalinity, since exceeding certain Ω-thresholds for a given water composition may lead to carbonates formation, causing the loss of previously added alkalinity. In this research, stability of alkalinity was tested using incubation experiments with Elbe estuary freshwater from two seasons (March and August).

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Peer-reviewed Publications

Raudsepp et al. (2025): The fate of CO₂, Ca, and Mg after terrestrial rock weathering

Maija J. Raudsepp, Sasha Wilson and Benjamin M. Tutolo, IN: Geology, https://doi.org/10.1130/G53354.1

The silicate−carbonate cycle controls atmospheric CO₂ concentrations and moderates Earth’s climate over geologic time scales. Chemical weathering of silicate minerals by CO₂ results in the release of cations and the neutralization of CO₂ to HCO₃⁻ or CO₃²⁻. The precipitation of Ca- and Mg-carbonate minerals is expected once waters are supersaturated. However, quantifying the magnitude of supersaturation required, particularly for Mg-carbonates, has remained challenging. Here the authors present a database of 854 water samples from the Central Plateau, British Columbia, Canada, representing a wide range of salinities, including both Na−(SO₄)−HCO₃−CO₃ and Mg−Na−SO₄ hypersaline lakes, to determine the geochemical thresholds for Ca- and Mg-carbonate formation.

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Peer-reviewed Publications

Desmalles et al. (2025): Impact of Basalt Rock Powder on Ryegrass Growth and Nutrition on Sandy and Loamy Acid Soils

Charles Desmalles, Lionel Jordan-Meille, Javier Hernandez, Cathy L. Thomas, Sarah Dunham, Feifei Deng, Steve P. McGrath and Stephan M. Haefele, IN: Agronomy, https://doi.org/10.3390/agronomy15081791

Enhanced weathering of silicate rocks in agriculture is an option for atmospheric CO₂ removal and fertility improvement. The objective of the authors’ work is to characterise some of the agricultural consequences of a basaltic powder amendment on soil-crop systems. Two doses of basalt (80 and 160 t ha⁻¹) were applied to two types of slightly acid soils (sandy or silty clayey), derived from long-term trials at Bordeaux (INRAE, France) and Rothamsted Research (England), respectively. For each soil, half of the pots were planted with ryegrass; the other half were left bare.

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Peer-reviewed Publications

Buma et al. (2025): Expert elicitation on agricultural enhanced weathering highlights CO₂ removal potential and uncertainties in loss pathways

Brian Buma, Christiana Dietzen, Doria Gordon, Katharine Maher, and 20 more, IN: Research Square, https://doi.org/10.21203/rs.3.rs-7040857/v1

Enhanced weathering (EW) in agriculture is a potential gigatonne-scale carbon dioxide removal (CDR) pathway. The true scale of potential CDR remains difficult to constrain due to its complexity across the entire field-to-ocean pathway and a paucity of system-level empirical data. The authors used a formal expert elicitation process to quantify the ranges of best CDR estimates, uncertainties, and key data needs for six EW feedstocks. Expert opinion of the CDR potential varied by feedstock, with estimates averaging 0.2–0.7 Gt CO₂e/yr, but with a wide range (less than zero to greater than 5 Gt CO₂e/yr). The efficiency of CDR, meaning the fraction of potential CDR ultimately realized from a given amount of material applied ranged from 27–39%. Key constraints included feedstock availability at scale (especially for wollastonite), calcite saturation, secondary clay formation, and deep soil/freshwater emission pathways.

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