This paper explores three methods for removing carbon dioxide from the atmosphere by applying specific minerals to soil, utilising both organic and inorganic pathways to capture and stabilise carbon. The methods discussed include enhanced rock weathering, where crushed calcium- and magnesium-rich rocks are spread on soil to convert atmospheric CO₂ into stable inorganic carbon; mineral doping of biomass to increase biochar carbon stability, which enhances biochar's long-term carbon retention; and strategic mineral applications to increase soil organic carbon stability. Each approach uses naturally occurring interactions in soil to support carbon retention, though they have primarily been studied independently.

The paper aims to demonstrate potential synergies between these methods that could improve carbon capture efficiency and economic feasibility. The authors first review each technique, outlining the necessary chemical and biological interactions, then examine the types of minerals suited for each method and discuss environmental conditions that may enhance effectiveness. The study highlights the advantages of integrating different mineral-based techniques to support more robust and lasting CO₂ removal. By quantifying these synergies, the authors hope to guide future research and practical applications in carbon capture.

This paper investigates the regional variability in costs, energy demands, and carbon footprints associated with feedstock grinding for Enhanced Rock Weathering (ERW) across the coterminous United States. Recognizing that feedstock grinding is the most energy-intensive step in the ERW lifecycle, the paper performs a state-level geospatial analysis to understand how these factors vary with particle size and local electricity mixes. The study aims to provide a more detailed and accurate life cycle analysis (LCA) specific to the U.S., aiding in the development of economically and technically feasible large-scale deployment strategies for ERW. Key Points:

This paper explores the potential of Enhanced Rock Weathering (ERW) as a method for greenhouse gas removal in the UK. ERW involves the application of finely ground rock to land surfaces, where it interacts with rainwater to convert dissolved CO₂ into stable minerals within the soil. The paper discusses the various factors that influence the efficiency and scalability of ERW, including the type of rock used, soil conditions, and climate. It also examines the current gaps in research, such as the limited number of long-term field trials and the lack of standardized methods for measuring and verifying carbon capture. Additionally, the paper addresses the potential environmental risks and barriers to large-scale implementation, particularly in the context of the UK, where the production of rock dust through quarrying and crushing could present significant challenges. The study highlights the need for further research to assess these risks and to develop more reliable techniques for carbon dioxide removal and verification.

Provides an extensive overview of CCS opportunities in Oman, examining both surface and subsurface options. It investigates the stratigraphy of Oman, focusing on the potential of ultramafic rocks, subsurface sequences, and structural and stratigraphic traps for effective CO₂ sequestration. The study assesses the potential of utilizing producing hydrocarbon fields and deep saline aquifers for CCS, as well as the possibility of creating underground salt caverns in Late Proterozoic to Cambrian evaporites. The methodology includes ranking these CCS opportunities based on various criteria, considering factors such as reservoir pressure support, storage potential, and geological stability. This comprehensive analysis aims to identify the most viable CCS strategies for Oman to enhance hydrocarbon recovery and long-term CO₂ storage.

This paper explores the first laboratory experiments involving CO₂ injection into continental flood basalts in South America. It investigates the mineral composition, texture, and reaction kinetics of these basalts to understand their potential for rapid carbonate precipitation. The study focuses on the Paraná basin, a significant geological formation with extensive layers of continental flood basalts, which presents an opportunity for effective CCS. The methodology includes analyzing the availability of calcium and chemical monitoring to estimate the CO₂ storage potential. The paper emphasizes the advantages of using basaltic formations over other geological reservoirs for CCS, highlighting their high mineral reactivity and long-term storage capabilities.

Presents findings from a long-term, large-scale enhanced weathering (EW) field trial in the US Corn Belt, focusing on carbon dioxide removal (CDR) and agronomic benefits. The study evaluates the application of crushed basalt on maize-soybean rotation fields, assessing both carbon sequestration and impacts on soil fertility and crop yield over four years. The trial aims to determine the practicality and effectiveness of EW as a CDR strategy in commercial farming, with specific attention to its integration into current agricultural practices without sacrificing crop productivity.

Discusses a collaborative initiative between Precision Development (PxD) and the Institute for Governance & Sustainable Development (IGSD) to identify climate change mitigation opportunities, particularly focusing on smallholder farmers in the Global South. It explores innovations for addressing greenhouse gases like methane, nitrous oxide, and carbon dioxide prevalent in agricultural production.

This paper explores the application of enhanced weathering (EW) using crushed silicate rocks in agricultural soils to improve carbon sequestration and enhance soil health. Focusing on conventional row crops and bioenergy crops, it addresses the potential to utilize EW for both food and fuel production lands. The research underscores the current agricultural practices that contribute to carbon loss and how EW can offset these effects by stabilizing soil pH and enhancing nutrient availability. The methodology involves evaluating different crop systems, particularly emphasizing perennial bioenergy crops, which may benefit more significantly from EW due to their extensive root systems and longer growth periods.

This paper examines the potential and costs associated with enhancing the natural process of rock chemical weathering for carbon dioxide removal (CDR). It provides a detailed techno-economic assessment that includes economic costs, energy requirements, and technical parameterization to evaluate the feasibility of this method in achieving substantial CO₂ removal from the atmosphere. The study particularly focuses on the variables of grain size and weathering rates, highlighting their impact on the effectiveness of CDR through enhanced weathering. It compares the suitability and potential negative side effects of using dunite and basaltic rocks, assessing their efficiency and cost-effectiveness in different global regions, particularly in warm and humid climates.

This paper investigates the potential of enhanced weathering (EW) in the UK, focusing on the carbon capture capabilities through the dissolution of silicate minerals. The study presents an energy and carbon balance, alongside the operational costs for implementing EW in the UK, using basic and ultrabasic rock formations. It addresses the energy requirements, primarily from comminution and material transport, and the associated costs of these operations. The paper also discusses the environmental considerations and the need for further research to clarify the weathering rates and impacts of silicate mineral application on land.

This paper evaluates the potential risks associated with terrestrial enhanced rock weathering as a carbon dioxide removal strategy, specifically the accumulation of toxic trace elements in soils. The study critically assesses whether the recommended global application rate of ground basaltic rock could lead to soil concentrations of trace elements like copper and nickel exceeding legal limits. By comparing different scenarios using various rock sources and application rates within the context of national regulatory frameworks, the research seeks to determine the temporal threshold at which these limits might be breached. The findings suggest a need for precise tailoring of ERW deployment to local conditions to balance its climate mitigation benefits against the risk of soil degradation.

The paper focuses on Coastal Enhanced Weathering (CEW) as a method for carbon dioxide removal, where crushed silicate minerals like olivine are dispersed in coastal zones. This process leverages natural forces such as waves and tidal currents to enhance the weathering of the mineral, which absorbs CO₂ from the atmosphere. A Life Cycle Assessment (LCA) was conducted to evaluate the environmental impacts and effectiveness of using different particle sizes of olivine. The LCA provides insight into the trade-offs between the speed of CO₂ uptake, the environmental footprint of different particle sizes, and the logistical challenges involved in the process. The assessment highlights the importance of considering multiple environmental factors, beyond just carbon balances, to fully understand the impacts of CEW.

Investigates the environmental and health impacts of implementing enhanced rock weathering as a carbon dioxide removal (CDR) strategy, detailing the life cycle assessment (LCA) of ERW processes across twelve countries. By accelerating the natural geological carbon sequestration process, ERW uses crushed calcium and magnesium-rich silicate rocks to draw CO₂ from the atmosphere, which can help mitigate climate change impacts when applied to agricultural soils. The study assesses the entire ERW supply chain, from mining to spreading on croplands, under two future energy scenarios to 2050. It aims to understand the sustainability of ERW by examining the environmental impacts per unit area and total impacts per country, using the ReCiPe assessment method. This comprehensive analysis highlights the critical role of energy scenarios in determining the net carbon dioxide removal efficiency and environmental sustainability of ERW deployment.

This paper discusses the potential of powdered basalt as a soil amendment for removing CO₂ from the atmosphere, a technique under the umbrella of negative emission technologies aimed at climate change mitigation. By focusing on basalt's dual capability to enhance soil fertility and react with atmospheric CO₂, the study explores the broader implications of this nature-based solution. The paper emphasizes the readiness of this technology for integration into existing land management systems and considers the logistics and sustainability of upscaling basalt application, highlighting the need for further research on its environmental impacts and practical deployment at scale.

Overview:

This paper explores the role of enhanced rock weathering deployment with agriculture as a negative emission technology (NET) to mitigate future warming and protect coral reefs, emphasizing co-benefits and opportunities for carbon removal.

Key Points:

• Introduction to ERW: ERW on croplands is proposed as a NET to achieve net-zero carbon emissions, offering co-benefits for agriculture, soils, and ocean acidification.
• Probability Enhancement: ERW deployment with croplands to remove 2 Gt CO₂ yr-1 doubles the probability of meeting the Paris 1.5 °C target by 2100 in a high mitigation climate scenario.
• Comparison with CCS: ERW has an equivalent effect on carbon removal as CCS at the same rate, with potential tripled chances of meeting a 1.5 °C target when co-deployed.
• Impact on Ocean Acidification: ERW deployment may reverse about one-third of the surface ocean acidification effect caused by atmospheric CO₂ increases over the past 200 years, offering a co-benefit for marine calcifying ecosystems.
• Benefits for Coral Reefs: ERW increases the percentage of coral reefs above an aragonite saturation threshold of 3.5, highlighting a significant co-benefit for coral reef preservation compared to CCS.
• Limitations: While ERW deployment shows promise, its effectiveness in ocean state recovery is uncertain, emphasizing the need for rapid CO₂ emissions reductions in the near term.

The abstract discusses Enhanced Silicate Weathering (ESW) as a Negative Emission Technology (NET) for actively removing CO₂ from the atmosphere. It emphasizes the significant potential of ESW to contribute to climate change mitigation and notes discrepancies between laboratory and real soil conditions. The abstract suggests that the effectiveness of ESW could be largely influenced by biological processes in the soil, such as the activity of plants, microbes, and macro-invertebrates, which have been shown to affect weathering rates but are often overlooked in lab studies. It advocates for more comprehensive research that includes these biological interactions to fully assess the potential of ESW as a climate change mitigation strategy.

This paper explores the potential of enhanced weathering (EW) as a negative emission technology (NET) to bolster biomass production and influence soil hydrology. It delves into the deployment of EW to supply essential nutrients to areas of afforestation-reforestation and bioenergy grasses that are phosphorus-deficient. The study leverages stoichiometric ratios and biomass estimates from vegetation models to evaluate nutrient demands and the resulting carbon sequestration potential, while also assessing the impact of basalt powder application on soil hydrological properties.

This paper examines the potential risks and co-benefits of CO₂ removal through enhanced weathering (EW) and ocean alkalinity enhancement (OAE) for marine pelagic ecosystems (marine environments characterized by their open water, away from the shore or bottom)

Key Points:

• CO₂ Removal Challenge: To limit global warming, hundreds of gigatons of CO₂ need removal by the end of the century, with EW and OAE proposed as potential solutions.
• Enhanced Weathering and Ocean Alkalinity Enhancement: EW and OAE involve accelerating weathering reactions of minerals to consume CO₂, potentially releasing mineral dissolution products.
• Potential Consequences for Pelagic Communities: Assessing the maximum additions of mineral dissolution products indicates high perturbation potentials for certain elements like Fe and Si, with implications for pelagic ecosystems
• Side Effects Qualification: Fe, Ni, and Si may have intermediate to high potential for side effects, while Ca and Mg show lower potential, with variations based on mineral type and location.
• Ecological/Biogeochemical Implications: The choice of minerals used in EW/OAE can influence ecological and biogeochemical consequences, potentially benefiting specific marine organisms like calcifiers or silicifiers.
• Call for Research: Dedicated research is needed to assess the risks and co-benefits of mineral dissolution products on marine and other environments before implementing EW and OAE at a planetary scale.

Investigates the potential of enhanced silicate rock weathering and soil carbonation for carbon dioxide sequestration in São Paulo State, Brazil. It particularly focuses on the basaltic rocks extracted from the Paraná Basin and their use in carbon dioxide removal practices through a detailed Life Cycle Assessment (LCA). The study analyzes the environmental impact of transportation and overall emissions related to the deployment of these rocks in agriculture, providing a balanced view of their net effectiveness in greenhouse gas removal.

Reviews the potential of enhanced weathering (EW) using crushed reactive silicate rocks, like basalt, across tropical agricultural and tree plantations to assist in carbon capture and storage efforts. It examines the suitability of warm tropical climates and their prolific crop production as key factors that could increase weathering rates. While acknowledging potential benefits such as improved crop yields and soil health, the paper also addresses significant concerns. These include environmental impacts from mining, energy consumption for rock processing, and potential negative effects on biodiversity from increased silicate runoff. The research outlines priority areas for further investigation into EW's application in tropical regions, considering factors like particle size, soil type, and ecological effects.

Presents a comprehensive study on the potential of Enhanced Rock Weathering (ERW) on croplands to sequester carbon dioxide (CO₂) on a global scale. Utilizing a 1-D reactive transport model called SCEPTER, the study simulates ERW at approximately 1,000 agricultural sites worldwide, focusing on the application of basalt dust. The research explores the interaction between ERW and varying climate conditions, assessing how regional climates impact the efficiency of this negative emissions technology. Additionally, the paper examines the resilience of ERW under global warming scenarios, investigating the economic implications for its implementation, especially in hot and humid environments. The study also considers the practicality of large-scale ERW deployment by addressing issues related to material weathering efficiency and optimization strategies to enhance cost-effectiveness.

Explores the feasibility of enhanced weathering (EW) as a carbon dioxide removal strategy in cropland soils, using direct measurements from a corn cropping system in California. Focusing on soil-applied crushed silicate rocks, like metabasalt and olivine, the study tests the effectiveness of EW under arid conditions. Through field testing during an extreme drought, it documents a significant increase in soil pore water bicarbonate alkalinity, indicating rapid CO₂ sequestration. This research addresses the gap in direct field evidence supporting the potential of EW to mitigate atmospheric CO₂, even in moisture-limited environments.

Explores the potential of using Greenlandic glacial rock flour for CO₂ sequestration through enhanced weathering in agricultural soils. It introduces a new method for adjusting CO₂ uptake calculations to reflect the influence of soil pH and partial pressure of CO₂ (pCO₂), focusing on the effects of non-carbonic acids in acidic environments. By establishing a practical protocol to quantify CO₂ uptake, the study aims to provide a more accurate assessment of how effectively silicate mineral weathering can contribute to carbon capture, especially in soils with lower pH values.

This study explores the application of crushed basalt on UK agricultural soil to enhance weathering rates and CO₂ drawdown in a controlled environment mimicking natural conditions. Using soil cores treated with basalt and monitored over 14 months, the research provides a detailed assessment of basalt dissolution and its impact on soil chemistry and potential CO₂ removal. This methodological approach seeks to bridge the gap between laboratory simulations and actual field conditions, offering insights into the effectiveness of enhanced weathering under specific environmental constraints such as low water availability in dry croplands.

Examines a large-scale field trial of enhanced rock weathering on an oil palm plantation in Sabah, Malaysia, to assess its effectiveness in atmospheric CO₂ removal. Over three years, crushed silicate rock was applied to specific catchments, and comparisons were made with untreated adjacent catchments. The focus of the study is on observing CO₂ drawdown through changes in stream water alkalinity and soil carbonate content, rather than solely relying on theoretical models. This real-world application provides critical insights into the practical deployment of ERW and its potential scalability.

Investigates the integration of enhanced weathering (EW) with cotton farming in Thessaly, Greece, as part of the broader Project Carbdown. It focuses on utilizing local ultramafic rocks rich in olivine for EW in an effort to improve carbon dioxide removal (CDR) efficiencies in agricultural settings. The trial aims to assess the practicality and effectiveness of EW by combining it with the irrigation practices of cotton cultivation, which dominates the region. The study examines the potential scalability of this CDR method by leveraging the existing agricultural infrastructure without competing for arable land needed for food production. The selection of the Thessaly region is strategic due to its extensive cotton fields and the unique geological features that may enhance EW.

Explores the carbon sequestration capabilities of peridotites and basalts through enhanced weathering in seawater, employing open system experiments with batch reactors at ambient conditions. The study contrasts the effects of ultrafine ground peridotites against basalts in artificial seawater to assess their ability to draw CO₂ directly from the atmosphere and precipitate carbonate minerals. The findings reveal differing effectiveness between rock types and processing methods, highlighting the influence of particle size on the weathering process and subsequent CO₂ sequestration.

This paper investigates CO₂ consumption by chemical weathering in the Tao He, Huang Shui, and Datong He rivers, which originate from the northeastern Qinghai-Tibet Plateau (QTP). The study focuses on understanding the chemical weathering mechanisms in the QTP sections, the transition zones between the QTP and the Loess Plateau (LP), and the LP sections of these rivers. The authors address the spatial variability of chemical weathering in these areas, considering the influence of complex lithologies, climatic and tectonic zones, and anthropogenic activities. They highlight the necessity of examining these regions due to their high chemical weathering rates and potential impact on global CO₂ consumption. The paper also compares seasonal variations in CO₂ consumption by chemical weathering among the three rivers and contrasts these findings with other regions to better understand the broader implications for the global carbon cycle.

The paper explores the role of silicate rock weathering as a global carbon sink, utilizing high-precision data from 1996-2017 and future projections for 2041-2060 based on the Celine model. It addresses the understanding of the global silicate rock weathering carbon sink (SCS) by quantifying its magnitude and distribution, and predicting future trends under different greenhouse gas emission scenarios. By creating a detailed spatial dataset, the research clarifies the current status and potential future developments of SCS in light of increasing temperatures, providing a foundation for assessing the impact of climate change on this natural process.

Investigates the influence of chemical weathering on CO₂ consumption in the Bishuiyan subterranean basin, Guangxi, China. It utilizes water chemistry equilibria methods to analyze water chemistry, focusing on the contributions of carbonate and silicate weathering to the ionic composition of the waters. The study highlights the higher ion concentrations in the basin compared to global averages, emphasizing the roles of Ca2+ and HCO₃₊^-, and the notable presence of SO₄2- and NO₃₊^-. It examines the primary ionic contributors to the dissolved load balance, revealing that carbonate weathering dominates, followed by silicate weathering and atmospheric input. Additionally, the paper explores the impact of atmospheric CO₂ and allogenic acids on rock weathering. The quantitative analysis provides insights into the weathering rates and the carbon sink effects of carbonate and silicate weathering, offering a comprehensive baseline for understanding the chemical weathering processes in small watersheds with varying lithological characteristics.

This paper explores the contribution of highly active weathering regions to global CO₂-consumption by chemical weathering of silicates. It addresses the influence of silicate/carbonate weathering ratios on long-term climate changes. The study highlights the need for high-resolution representation of these regions due to their potential significance for global climate change. The paper examines previous approaches for estimating global CO₂-consumption and identifies gaps in spatial resolution and lithological classification. To improve accuracy, the authors apply a high-resolution CO₂-consumption model to a global vector-based lithological map with 15 lithological classes, calibrated with data from areas representing a wide range of weathering rates. This enhanced classification scheme aims to better represent CO₂-consumption from various sedimentary rocks and their diagenetic histories, revealing the importance of distinguishing among sediment types to evaluate rock weathering distribution.

This paper investigates the role of living organisms, particularly microorganisms, in the process of rock weathering within the critical zone. It emphasizes the significant, yet often overlooked, contribution of bacteria and fungi to weathering. The study explores the quantitative impact of these organisms on mineral degradation, the mechanisms involved, and the distinctive imprints left on mineral surfaces and geological records. It also examines whether biogenic weathering serves an ecological function or is merely a byproduct of other metabolic activities. Additionally, the paper reviews efforts to incorporate the role of living organisms into reactive transport models and discusses potential applications of microbial weathering in sustainable practices, such as agroforestry, mining, soil remediation, and carbon sequestration.

Investigates the potential of different silicate minerals for enhanced weathering applications aimed at improving soil quality and sequestering carbon dioxide (CO₂). By comparing minerals like olivine, basalt, wollastonite, anorthite, and albite, the study assesses their effectiveness in both enhancing soil productivity through pH adjustment and nutrient release, and in capturing CO₂. A down-flow soil column experiment facilitated detailed measurements of soils and leachates, and the calculation of carbon budgets, revealing varied results across the minerals tested.

Overview:

This paper focuses on evaluating UK mineral resources suitable for Enhanced Rock Weathering (ERW) and assessing their potential environmental and social impacts for early-stage deployment of this approach.

Key Points:

• Evaluation of Mineral Resources: The paper provides a spatial inventory of basic silicate rock resources in the UK, along with current production capacity and permitted reserves, essential for understanding ERW scalability.
• Identification of Quarries: 68 active and 100 inactive quarries were identified within outcrops of basic silicate rocks, mainly located in Northern Ireland and the central belt of Scotland.
• Estimation of Extraction: Approximately 14.8 Mt yr-1 of basic silicate rock are extracted, with up to 3.7 Mt yr-1 of basic silicate waste fines potentially available for ERW in the UK.
• Assessment of Permitted Reserves: 490 Mt of permitted reserves are associated with active and inactive quarries, indicating the availability of resources for ERW.
• Inclusion of Artificial Alkaline Minerals: The inventory includes spatial distribution data of artificial alkaline minerals like Construction and Demolition Wastes (CDW) and legacy slags in the UK.
• Calculating Transport Distances: Transport distances are calculated between all resources and the UK's croplands to determine the feasibility of applying these materials for ERW.

This paper investigates how rock-derived primary minerals, through weathering processes, transform into reactive, poorly crystalline minerals that play a crucial role in soil organic carbon storage. The study uses a newly designed model to establish a connection between primary mineral weathering rates and the distribution of poorly crystalline minerals across the United States. It aims to address the lack of comprehensive testing of this relationship, particularly at large geographical scales, and evaluates how variations in weathering rates affect soil organic carbon levels. This analysis is pivotal for understanding the spatial limitations and potential of soil carbon storage influenced by rock weathering.

This paper explores the feasibility of using basalts in Enhanced Rock Weathering (ERW) for carbon dioxide removal. It focuses on a comprehensive characterization of the mineralogy, chemistry, and physical properties of six commercially available basalts, and how these factors influence their potential in carbon capture. The study employs a 1-D reactive transport modeling (RTM) to simulate the inorganic carbon dioxide removal capacity and the release of essential plant nutrients in a typical agricultural soil. The findings are intended to guide the practical implementation of ERW, offering insights into optimizing material properties for effective carbon sequestration and agricultural benefits.

This paper explores the potential of enhanced basalt weathering on agricultural land as a carbon dioxide removal strategy, focusing on the effects of particle size on sequestration effectiveness. Through a detailed regional assessment, it reviews the current state of research and models CO₂ drawdown scenarios using different basalt powder sizes. The study emphasizes the importance of particle size, showing that smaller grains significantly increase dissolution rates and, therefore, CO₂ sequestration potential. It integrates considerations of the entire lifecycle, from mining to transport, to assess the net impact of basalt application. The paper highlights the unresolved uncertainties in field weathering rates and the need for further research to optimize this technology for climate mitigation.

Overview:
This paper discusses the development of tools for Measurement, Reporting, and Verification (MRV) of Enhanced Weathering (EW) as a carbon dioxide removal (CDR) approach, focusing on soil-based methods.

Explores the monitoring, reporting, and verification (MRV) challenges associated with quantifying carbon dioxide (CO₂) removal at enhanced weathering sites. Focusing on a long-term weathering site in Consett, Co. Durham, UK, the study introduces a multiproxy approach to accurately assess the rate of carbon removal from the atmosphere using steel slags. By analyzing radiocarbon, d13C, 87Sr/86Sr, and major element data in waters, calcite precipitates, and soils, the research provides insights into the effectiveness of CO₂ mineralization and the potential for these practices to contribute to climate mitigation efforts.

Introduces a new empirical method to monitor enhanced rock weathering rates, essential for assessing its effectiveness as a carbon dioxide removal (CDR) strategy. The method focuses on mass balance and metal analysis in soil samples to track alkaline mineral weathering in situ. By using isotope-dilution mass spectrometry, the approach aims to reduce analytical errors and enhance the accuracy of CDR measurement in field settings. The paper details a controlled mesocosm experiment to illustrate the method's application and integration with conventional agricultural practices.

This paper evaluates the effectiveness and permanence of carbon storage through enhanced rock weathering using an ensemble of Earth system models. The study investigates how ERW, a proposed negative emissions technology, influences the long-term dynamics of carbon in the ocean and atmosphere. By comparing ERW to scenarios with modulated emissions, it provides new insights into the expected backflux of CO₂ and its implications for marine calcifying organisms. The analysis highlights ERW's potential to add net alkalinity to the ocean, which could benefit marine ecosystems, and underscores the need for including these dynamics in technoeconomic evaluations of ERW scalability.

Discusses the challenge of establishing a verifiable and cost-effective carbon accounting system for Enhanced Weathering (EW), a negative emission technology. Through laboratory scale column experiments and field observations, the study hypothesizes a correlation between total alkalinity and electrical conductivity as a potential low-cost indicator of initial CO₂ sequestration by chemical mineral weathering. It emphasizes the importance of developing this method to enable simplified and cost-effective CO₂ uptake monitoring, essential for incentivizing investments and facilitating CO₂ certificate trading.

This paper explores Enhanced Weathering (EW) as a method for carbon dioxide removal (CDR) in agronomic settings. It highlights the theoretical potential of EW to remove billions of tons of CO₂ annually from the atmosphere when applied in global working lands. The focus is on the need for increased field trials and the development of robust methodologies to quantify CO₂ removal effectively. By integrating geochemistry with agronomy through interdisciplinary research, the paper aims to advance the scientific verification of EW. It also discusses the importance of effective stakeholder engagement to translate research into practical action, providing a comprehensive guide for setting up EW field trials.

This paper explores the process of simulating carbon capture through enhanced weathering (EW) with croplands, focusing on key processes and areas for future model development.

Key Points:

• Enhanced Weathering (EW) Concept: EW involves incorporating powdered silicate rock into agricultural soils to accelerate CO₂ capture, aiming for rapid mineral dissolution and release of alkalinity.
• Goals of EW: EW could address phosphorus limitation, reduce greenhouse gas emissions in tropical soils, and counteract soil acidification, a longstanding agricultural concern.
• Review of Soil Acidification Processes: The paper reviews processes contributing to soil acidification in croplands and how soil weathering CO₂ sinks are represented in models.
• Modeling Challenges: Mathematical models typically focus on either agricultural processes or weathering, neglecting the integration of both, highlighting a gap in current modeling approaches.
• Current Approaches to Modeling EW: The paper discusses existing modeling approaches for EW and identifies potential classes of models capable of simulating EW in croplands.
• Need for Integration: There's a call for further integration of process knowledge into mathematical models to capture feedbacks impacting both CO₂ consumption and crop growth and yields.

Overview:

This paper examines public perceptions of enhanced rock weathering and its social and environmental implications, focusing on deliberative workshops held in England, Wales, and Illinois.

Key Points:

• Background of ERW: ERW involves accelerating rock weathering processes by finely crushing and spreading rocks on agricultural land, aiming to remove carbon dioxide from the atmosphere.
• Purpose of the Study: The study aims to understand public perceptions of ERW and its broader social and environmental impacts, recognizing its significance in achieving net-zero emissions goals.
• Methodology: Deliberative workshops held in different locations explored public views on ERW, considering its deployment in both Western agricultural contexts and tropical countries.
• Social Justice Perspective: Participants framed ERW deployment in tropical countries from a social justice perspective, highlighting concerns about potential detrimental social and environmental impacts and assumptions of increased scale.
• Iconic Environments: Risk perceptions regarding "messing with nature" were amplified when participants considered ERW in relation to iconic environments like oceans and rainforests, raising additional concerns.
• Implications for Governance: Understanding public perceptions and framing of ERW is crucial for its governance at scale, emphasizing the need for inclusive deliberation and consideration of diverse perspectives.

This paper explores the legal framework for enhanced weathering, a technique involving the spreading of silicate rocks or similar materials to remove carbon dioxide from the atmosphere.

Key Points:

• Background of Climate Change: Despite warnings about climate change, substantial greenhouse gas emissions persist, necessitating the removal of previously emitted gases from the atmosphere.
• Enhanced Weathering Technique: Enhanced weathering involves spreading finely ground silicate rocks over land or ocean waters, where they react with carbon dioxide, sequestering it in mineral form.
• Long-Term Carbon Storage: Initial research suggests enhanced weathering could result in the long-term storage of significant amounts of carbon dioxide, possibly for centuries or millennia.
• Legal Framework Examination: The paper investigates the international and U.S. legal framework for enhanced weathering, identifying potential laws applicable to such projects.
• International Instruments: Applicable international instruments may include the Convention on Biological Diversity and the United Nations Convention on the Law of the Sea, among others.
• Domestic Regulations: Projects could be subject to various U.S. federal and state laws, such as the Clean Water Act and Clean Air Act, depending on project specifics.

This paper presents urban farming integrated with enhanced rock weathering as a viable addition to climate mitigation strategies, aiming to achieve carbon neutrality. It explores the potential of urban areas-from rooftops to balconies-to serve as sites for carbon capture through the strategic use of soil and plants. The study advocates for ERW, a method known for its capacity to sequester atmospheric CO₂, to be employed alongside urban agriculture. This combination is proposed as a feasible and impactful method to utilize extensive urban spaces for food production and carbon sequestration, contributing to climate stabilization efforts.