Carbon Sequestration Opportunities Research Articles

A critical analysis of marine carbon sequestration opportunities in South Korea

South Korea has made significant commitments to pursuing marine carbon sequestration [including ‘blue carbon’] initiatives as part of its broader environmental and climate strategies. Specifically, the South Korean government has set a target to sequester 1,362,000 tonnes of CO₂ in the ocean by 2050 as part of its national strategy. Here, leveraging available data, we outline potential measures to achieve this goal, and provide critical insights into the scale and feasibility of marine carbon sequestration initiatives to inform policymakers and industry stakeholders. We investigated a wide range of potential approaches, ranging from traditional blue carbon approaches involving conservation and restoration of seagrass meadows and tidal marshes; to emerging strategies involving seaweed farming and mudflat restoration; to geoengineering interventions involving ocean alkalinity enhancement. Overall, we find that the South Korean Government target is achievable, largely through [in order of low to high abatement scaleability]: mudflat and saltmarsh conservation/restoration, seaweed conservation/restoration, seagrass conservation/restoration, seaweed farming and ocean alkalinity enhancement. However, we stress that our estimates are rudimentary and carry numerous assumptions/risks, and, moreover, carbon offset standards are still under consideration and development for some of these abatement approaches. In terms of ‘readiness to implement’, South Korea is strongest in seaweed carbon sequestration research and application, with a track record of successful restoration of tens of thousands of hectares of seaweed habitats over several decades. A coordinated national strategy will be needed to realise and establish South Korea’s marine carbon sequestration potential, supported by policy and finance. Fortunately, the marine carbon strategies proposed align with the country’s broader initiatives to enhance biodiversity, protect coastlines, and mitigate the impacts of climate change.

Opportunities for carbon sequestration from removing or intensifying pasture-based beef production

Pastures, on which ruminant livestock graze, occupy one third of the earth's surface. Removing livestock from pastures can support climate change mitigation through carbon sequestration in regrowing vegetation and recovering soils, particularly in potentially forested areas. However, this would also decrease food and fiber production, generating a tradeoff with pasture productivity and the ruminant meat production pastures support. We evaluate the magnitude and distribution of this tradeoff globally, called the "carbon opportunity intensity" of pastures, at a 5-arcminute resolution. We find that removing beef-producing cattle from high-carbon intensity pastures could sequester 34 (22 to 43) GtC i.e. 125 (80 to 158) GtCO2 into ecosystems, which is an amount greater than global fossil CO2 emissions from 2021-2023. This would lead to only a minor loss of 13 (9 to 18)% of the global total beef production on pastures, predominantly within high- and upper-middle-income countries. If areas with low-carbon intensity pastures and less efficient beef production simultaneously intensified their beef production to 47% of OECD levels, this could fully counterbalance the global loss of beef production. The carbon opportunity intensity can inform policy approaches to restore ecosystems while minimizing food losses. Future work should aim to provide higher-resolution estimates for use at local and farm scales, and to incorporate a wider set of environmental indicators of outcomes beyond carbon.

Soil Carbon Dioxide Emissions and Carbon Sequestration with Implementation of Alley Cropping in a Mediterranean Citrus Orchard.

Agroecological ecosystems produce significant carbon dioxide fluxes; however, the equilibrium of their carbon sequestration, as well as emission rates, faces considerable uncertainties. Therefore, sustainable cropping practices represent a unique opportunity for carbon sequestration, compensating greenhouse gas emissions. In this research, we evaluated the short-term effect of different management practices in alleys (tillage, no tillage, alley cropping with Rosmarinus officinalis and Thymus hyemalis on soil properties, carbon sequestration, and CO2 emissions in a grapefruit orchard under semiarid climate). For two years every four months, soil sampling campaigns were performed, soil CO2 emissions were measured, and rhizosphere soils were sampled at the end of the experimental period. The results show that alley cropping with Thymus and Rosmarinus contributed to improve soil fertility, increasing soil organic carbon (SOC), total nitrogen, cation exchange capacity, and nutrients. The CO2 emission rates followed the soil temperature/moisture pattern. Tillage did not contribute to higher overall CO2 emissions, and there were no decreased SOC contents. In contrast, alley crops increased CO2 emission rates, especially Rosmarinus; however, the bigger root system and biomass of Rosmarinus contributed to soil carbon sequestration at a greater rate than Thymus. Therefore, Rosmarinus is positioned as a better option than Thymus to be used as an alley crop, although long-term monitoring is required to evaluate if the reported short-term benefits are maintained over time.

Blue carbon habitats in Aotearoa New Zealand—opportunities for conservation, restoration, and carbon sequestration

Coastal marine habitats (i.e. mangroves, saltmarshes, and seagrasses) have a high capacity for carbon sequestration (termed “blue carbon”) and the potential to reduce the effects of greenhouse gas emissions. However, blue carbon habitats have historically decreased as a consequence of land conversion, coastal development, and pollution and are under threat in many locations. Restoration of these habitats can reverse historic losses and generate carbon credits through increased carbon sequestration. With a long coastline, we hypothesized that there would be significant opportunities for coastal blue carbon in Aotearoa New Zealand. Results revealed Aotearoa estuaries and coastal areas contain approximately 20,932 ha of saltmarsh, 30,533 ha of mangrove, and 61,340 ha of seagrass, estimated to sequester a total of approximately 57,800 tC/year. A further 87,861 ha of land was estimated to be potentially suitable for blue carbon projects via tidal restoration, of which 56,482 ha was suitable for saltmarsh restoration (equivalent to 60,435 tC yr if restored), 17,291 ha was suitable for mangroves (26,455 tC/year), and 14,087 ha was suitable for seagrass (4790 tC/year). Both existing extent and restoration opportunity varied throughout the country, with greater opportunity in some regions than others. Nationwide, the total sequestration potential for blue carbon restoration was estimated at 91,680 tC yr−1 if all potential areas were restored. Carbon credits generated by blue carbon projects could be traded on a carbon market in Aotearoa, generate revenue for landowners, provide an additional pathway to meet domestic and international climate change targets, and result in a diversity of other ecological, social, and cultural co‐benefits from coastal restoration.

Combining Steam and Flue Gas as a Strategy to Support Energy Efficiency: A Comprehensive Review of the Associated Mechanisms.

Conventional steam injection projects have long been an iconic process in the development of heavy oil reserves; nevertheless, they face significant challenges in terms of energy efficiency, environmental compliance, and economic viability. Factors such as oil price fluctuations, the imperative for an energy transition, and the push to reduce carbon footprints are hindering new or ongoing implementations of traditional steam injection technologies. In response to these challenges, hybrid methods, such as the combination of steam and flue gas, are emerging as an opportunity to optimize thermal processes to improve oil recovery, energy efficiency, and environmental sustainability and extend reservoir productivity life. Steam injection enhances oil recovery by reducing the viscosity of crude oil, improving oil mobility and facilitating its extraction. The utilization of flue gas in steam injection processes has a significant impact on oil recovery and energy efficiency, leveraging industrial byproducts. This not only lowers operating costs but also reduces environmental emissions, aligned with energy transition trends. Incorporating the flue gas into a steam-based process in heavy oil reservoirs has emerged as a promising thermally enhanced oil recovery strategy. This work presents a comprehensive review based on experimental, numerical, and field studies of hybrid steam and flue gas technology as an EOR process. The main recovery mechanisms associated with the process are analyzed. In addition, the laboratory equipment required for experimental evaluations is presented, and reservoir modeling, kinetic and compositional effects on reservoir fluids, and the reduction in heat losses in the steam injection process are discussed. Furthermore, field implementations are reviewed to evaluate lessons learned and experiences on an operative scale. The combination of steam and flue gas represents an opportunity for carbon utilization and geological carbon sequestration. This dual functionality underscores its potential to enhance oil recovery and address carbon-related environmental concerns.

Restoring blue carbon ecosystems

Abstract Mangroves, tidal marshes and seagrasses have experienced extensive historical reduction in extent due to direct and indirect effects of anthropogenic land use change. Habitat loss has contributed carbon emissions and led to foregone opportunities for carbon sequestration, which are disproportionately large due to high ‘blue carbon’ stocks and sequestration rates in these coastal ecosystems. As such, there has been a rapid increase in interest in using coastal habitat restoration as a climate change mitigation tool. This review shows that restoration efforts are able to substantially increase blue carbon stocks, while also having a positive impact on various gaseous fluxes. However, blue carbon increases are spatially variable, due to biophysical factors such as climate and geomorphic setting. While there are potentially hundreds of thousands of hectares of land that may be biophysically suitable for restoration, these activities are still often conducted at small scales and with mixed success. Maximizing potential carbon gains through blue carbon restoration will require managers and coastal planners to overcome the myriad socioeconomic and governance constraints related to land tenure, legislation, target setting and cost, which often push restoration projects into locations that are biophysically unsuitable for plant colonization.

Carbon Storage Patterns and Landscape Sustainability in Northeast Portugal: A Digital Mapping Approach

This study investigated the impact of regional land abandonment in northeast Portugal. It specifically focused on carbon sequestration opportunities in the Upper Sabor River Watershed, situated in the northeast of Portugal, amidst agricultural land abandonment. The study involved mapping the distribution of soil organic carbon (SOC) across four soil layers (0–5 cm, 5–10 cm, 10–20 cm, and 20–30 cm) at 120 sampling points. The quantification of SOC storage (measured in Mg C ha−1) allowed for an analysis of its relationship with various landscape characteristics, including elevation, land use and land cover (LULC), normalized difference vegetation index (NDVI), modified soil-adjusted vegetation index (MSAVI), topographic wetness index (TWI), and erosion risk (ER). Six statistical tests were employed, including multivariate approaches like Cubist and Random Forest, within different scenarios to assess carbon distribution within the watershed’s soils. These modeling results were then utilized to propose strategies aimed at enhancing soil carbon storage. Notably, a significant discrepancy was observed in the carbon content between areas at higher elevations (>1000 m) and those at lower elevations (<800 m). Additionally, the study found that the amount of carbon stored in agricultural soils was often significantly lower than in other land use categories, including forests, mountain herbaceous vegetation, pasture, and shrub communities. Analyzing bi- and multivariate scenarios, it was determined that the scenario with the greatest number of independent variables (set 6) yielded the lowest RMSE (root mean squared error), serving as a key indicator for evaluating predicted values against observed values. However, it is important to note that the independent variables used in set 4 (elevation, LULC, and NDVI) had reasonably similar values. Ultimately, the spatialization of the model from scenario 6 provided actionable insights for soil carbon conservation and enhancement across three distinct elevation levels.

Desalination brines as a potential vector for CO2 sequestration in the deep sea

Desalination brines as a potential vector for CO2 sequestration in the deep sea

Manipulating hydrogen oxy-combustion through carbon dioxide addition

Manipulating hydrogen oxy-combustion through carbon dioxide addition

Regenerative agriculture: increasing plant diversity and soil carbon sequestration on agricultural landscapes

Soil carbon sequestration is a proposed method of mitigating climate change by removing atmospheric carbon dioxide and depositing it in soil. Sustainable agricultural systems such as regenerative agriculture are capitalizing on the opportunity for soil carbon sequestration to be a positive outcome of new land management practices. Regenerative agriculture is a soil-focused approach to farming with the goal of supporting soil health by increasing biodiversity and soil-focused practices. This article explores the possibility of regenerative agriculture’s land management practices to impact soil carbon sequestration via the promotion of plant biodiversity restoration. Examining studies testing the effects of three sustainable practices on soil carbon storage: agroforestry, crop diversification, and crop rotation, as well as native restoration efforts, a positive relationship is found between plant diversity and carbon sequestration. Agroforestry benefits carbon sequestration through stable deep-rooting systems and carbon storage in biomass. Crop diversification and rotation practices encourage nutrients to cycle into the soil and diversify soil microorganisms. The overall effectiveness of these practices in different environments, upper limits to carbon sequestration, and increased nitrogen requirements are possible limitations to these practices. However, the opportunity for plant diversity to restore soil health and carbon storage is critical. With Canada’s commitments to its 2030 emissions reduction targets, increasing sustainable agricultural action may present an opportunity to reduce carbon dioxide emissions substantially while remedying issues of biodiversity and food insecurity.

Soil carbon pools and fluxes following the regreening of a mining and smelting degraded landscape

Soil carbon pools and fluxes following the regreening of a mining and smelting degraded landscape

Reclaimed Salt-Affected Soils Can Effectively Contribute to Carbon Sequestration and Food Grain Production: Evidence from Pakistan

Salt-affected soil reclamation provides opportunities for crop production and carbon sequestration. In arid regions such as Pakistan, limited studies have been reported involving soil reclamation and crop production under wheat–maize rotation, but no study has reported predictions on long-term carbon sequestration in reclaimed soils for the treatments used in this study. Thus, a field-scale fallow period and crop production experiment was conducted for wheat–maize rotation on salt-affected soils in Pakistan for 3 years to check the effectiveness of organic amendments for reclamation of the salt-affected soils, carbon sequestration and food grain production. Treatments used were the control (with no additional amendments to reduce salinity), gypsum alone and gypsum in combination with different organic amendments (poultry manure, green manure, and farmyard manure). The treatment with gypsum in combination with farmyard manure was most effective at increasing soil carbon (+169% over the three-year period of the trial). The maximum wheat yield was also recorded in year 3 with gypsum in combination with farmyard manure (51%), while the effect of green manure combined with gypsum also showed a significant increase in maize yield in year 3 (49%). Long-term simulations suggested that the treatments would all have a significant impact on carbon sequestration, with soil C increasing at a steady rate from 0.53% in the control to 0.86% with gypsum alone, 1.25% with added poultry manure, 1.69% with green manure and 2.29% with farmyard manure. It is concluded that food crops can be produced from freshly reclaimed salt-affected soils, and this can have added long-term benefits of carbon sequestration and climate change mitigation.

Net Zero: Actions for an Ocean-Climate Solution

It has long been understood that stabilizing the global climate requires human carbon emissions to converge toward net zero (Matthews and Caldeira, 2008). Analysis by the Intergovernmental Panel on Climate Change (IPCC) suggests delays in achieving net zero emissions, or a temperature increase of more than 1.5°C, will necessitate even stronger action: net negative emissions. A very large-scale opportunity for carbon sequestration would include yet unproven ocean-based carbon dioxide removal (CDR) technologies (Rogelj et al., 2018).

Smallholder farms have and can store more carbon than previously estimated.

Increasing soil organic carbon (SOC) stocks is increasingly targeted as a key strategy in climate change mitigation and improved ecosystem resiliency. Agricultural land, a dominant global land use, provides substantial challenges and opportunities for global carbon sequestration. Despite this, global estimates of soil carbon sequestration potential often exclude agricultural land and estimates are coarse for regions in the Global South. To address these discrepancies and improve estimates, we develop a hybrid, data-augmented database approach to better estimate the magnitude of SOC sequestration potential of agricultural soils. With high-resolution (30 m) soil maps of Africa developed by the International Soils Database (iSDA) and Malawi as a case study, we create a national adjustment using site-specific soil data retrieved from 1160 agricultural fields. We use a benchmark approach to estimate the amount of SOC Malawian agricultural soils can sequester, accounting for edaphic and climatic conditions, and calculate the resulting carbon gap. Field measurements of SOC stocks and sequestration potentials were consistently larger than iSDA predictions, with an average carbon gap of 4.42 ± 0.23 Mg C ha-1 to a depth of 20 cm, with some areas exceeding 10Mg C ha-1 . Augmenting iSDA predictions with field data also improved sensitivity to identify areas with high SOC sequestration potential by 6%-areas that may benefit from improved management practices. Overall, we estimate that 6.8million ha of surface soil suitable for agriculture in Malawi has the potential to store 274 ± 14 Tg SOC. Our approach illustrates how ground truthing efforts remain essential to reduce errors in continent-wide soil carbon predictions for local and regional use. This work begins efforts needed across regions to develop soil carbon benchmarks that inform policies and identify high-impact areas in the effort to increase SOC globally.

Opportunities for carbon sequestration in intensive soft fruit production systems

Abstract The historical contribution of agriculture to human-induced climate change is indisputable; the removal of natural vegetation and soil cultivation to feed the growing human population has resulted in a substantial carbon transfer to the atmosphere. While maintaining their food production capacity, soft fruit production systems now have an opportunity to utilise a recent technology change to enhance their carbon sequestration capacity. We use an example of a farm in South-East England to illustrate how the soft fruit crop production system can be optimised for carbon storage. We performed an audit of carbon stocks in the soil and tree biomass and show that it is imperative to plan crop rotation to establish (semi) permanent inter-row strips that will remain in situ even if the main crop is replaced. These strips should be covered with grassland vegetation, preferable with deeper rooting grass species mixed with species supporting nitrogen fixation. Finally, grassland mowing cuttings should be left in situ and hedgerows and tree windbreaks should be expanded across the farm. Modern soft fruit production systems can enhance their carbon storage while maintaining commercially relevant levels of productivity.

Soil organic carbon in Andean high-mountain ecosystems: importance, challenges, and opportunities for carbon sequestration

Soil organic carbon in Andean high-mountain ecosystems: importance, challenges, and opportunities for carbon sequestration

Rural land abandonment is too ephemeral to provide major benefits for biodiversity and climate.

Hundreds of millions of hectares of cropland have been abandoned globally since 1950 due to demographic, economic, and environmental changes. This abandonment has been seen as an important opportunity for carbon sequestration and habitat restoration; yet those benefits depend on the persistence of abandonment, which is poorly known. Here, we track abandonment and recultivation at 11 sites across four continents using annual land-cover maps for 1987–2017. We find that abandonment is largely fleeting, lasting on average only 14.22 years (SD = 1.44). At most sites, we project that >50% of abandoned croplands will be recultivated within 30 years, precluding the accumulation of substantial amounts of carbon and biodiversity. Recultivation resulted in 30.84% less abandonment and 35.39% less carbon accumulated by 2017 than expected without recultivation. Unless policymakers take steps to reduce recultivation or provide incentives for regeneration, abandonment will remain a missed opportunity to reduce biodiversity loss and climate change.

Energy production and well site disturbance from conventional and unconventional natural gas development in West Virginia.

Natural gas production from the Appalachian region has reached record levels, primarily due to the rapid increase in development of unconventional oil and gas (UOG) resources. In 2020, over 65,000 conventional wells reported natural gas production; however, this only represented 5% of the total natural gas produced. The remaining 95% of natural gas production can be attributed to 3,901 UOG wells. There has been a wide body of research on disturbance trends related to unconventional development in the region; however, there is limited characterization of disturbance related to production of conventional oil and gas (COG) or research that details energy production in relation to land disturbance. This study compares land disturbance from COG and UOG development as well as energy production. Land disturbance related to COG and UOG development was assessed for wells drilled during 2009–2012. Production data were summarized for the same wells during the period of 2009–2020. The average area disturbed for COG pads was 0.82 ha while UOG pads disturbed 4.02 ha. Results from this study showed that COG wells disturbed significantly less land area during construction; however, UOG wells produced almost 28 times more energy per hectare of land disturbed. This energy production imbalance as well as the over 65,000 COG wells reporting production in 2020, indicates that the retirement and restoration of COG infrastructure could be done without significantly impacting total energy production. Continued research that includes ecosystem services and carbon sequestration opportunities in relation to production losses from retiring existing infrastructure should be considered.Graphical abstract

Nature-Based Solutions in Sub-Saharan Africa for Climate and Water Resilience: A Methodology for Evaluating the Regional Status of Investments in Nature-Based Solutions from a Scan of Multilateral Development Bank Portfolios

This technical note outlines the methodology used to create a region-wide dataset of projects that have implemented NBS for climate- and water-resilience objectives in two multilateral development bank (MDB) portfolios — the World Bank and the African Development Bank. The resulting dataset includes 85 projects led by these MDBS over a 10-year period (2012‒21), including 46 projects from the World Bank and 39 projects from the African Development Bank. Total budgets for World Bank projects were $7.9 billion (including $2.5 billion for components with NBS), and total budgets for African Development projects $4.2 billion (including $2 billion for components with NBS). The countries with the largest number of projects were Ethiopia (10), Ghana (7), Malawi (7), Tanzania (6), Uganda (6), and Democratic Republic of the Congo (5). The technical note also demonstrates how these projects are leveraging NBS to address urgent challenges faced by communities in SSA, including urban flooding, coastal flooding, and water security. Additionally, the note illustrates numerous types of co-benefits that NBS are generating, including biodiversity, livelihoods, and opportunities for carbon sequestration.

Techno-socio-economic analysis of geological carbon sequestration opportunities

Although geological carbon sequestration is considered one of the pillars required to achieve the goals of the Paris Agreement, only a few demonstration sites are currently being developed around the globe. A workflow is presented here to identify potential new pilot sites.