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Forests are the largest pool of carbon in terrestrial ecosystems and are important for climate change mitigation. By analyzing the carbon sequestration process of forest ecosystem, the carbon sequestration amount of forest can be modeled as a nonlinear function, and the mechanism of forest carbon sequestration can be discussed on this basis. The research first introduced the relevant theories of forest carbon sequestration, followed by the preparation of the visualization system construction based on the research area and data sources, and then the construction of the visualization system, and finally carried out the simulation verification. The results show that the system is effective and accurate. [ABSTRACT FROM AUTHOR]

Mitigation pathways that stabilise global warming to 1.5 °C describe rapidly increasing deployment of land-based solutions, including increased carbon sequestration in soils and biomass. This places additional demands on land, which is also required to provide food security and other ecosystem services. Sustainable Intensification (SI) of agriculture has the potential to facilitate meeting demands for food and fibre, while simultaneously meeting environmental and ecological goals. The scientific literature has most often addressed the challenge of SI separately to climate change mitigation objectives in agricultural systems. Using a systematic review approach, we explored the compatibility of SI and carbon sequestration research through two contrasting case studies: Case Study I on Grassland Agriculture in Europe, and Case Study II on Smallholder Agriculture in Africa. We find contrasting levels of research theme similarity for SI and carbon sequestration, with European grassland agriculture research having lower similarity compared with African smallholder agriculture research. There was a focus on minimising biodiversity loss and environmental impacts in Europe, in contrast to a food security emphasis in Africa, reflecting regional and development differences. While there are clear context and agricultural-system specific differences between both case studies, both suggest that sustainable land use policies can be used to achieve SI integrated with climate mitigation in agriculture. • Climate mitigation pathways increasingly incorporate land-based carbon storage. • Sustainable intensification (SI) of agriculture may reduce demand for land. • We investigated the compatibility of research on SI and carbon sequestration. • There were significant contrasts reflecting a need for better integration. • Sustainable land use policies can help achieve mitigation where integrated with SI. [ABSTRACT FROM AUTHOR]

This study evaluates the environmental impacts associated with the conversion of garden organic waste into value-added products, namely compost or biochar, employing various processes. Three distinct scenarios are considered: composting garden organic waste followed by screening of oversized materials (CBP), pyrolysis of oversized screenings of compost into biochar AP(I), and in-situ conversion of garden organics into biochar AP(II). A comprehensive Life Cycle Assessment (LCA) was conducted using OpenLCA software and life cycle impact assessment was conducted using Recipe 2016 midpoint methodology. The environmental ramifications of each scenario were assessed, optimising transport distances in AP(II) to achieve a functional unit of one tonne of biochar produced within a cradle-to-gate system boundary. For the first time, this study offers a holistic exploration of the benefits of soil biochar application, extending its scope to climate change mitigation, incorporating the optimisation of transport distance and its influence when scaling up the technology. The results revealed that global warming was increased from 125 kgCO 2 eq during composting of garden waste to 232 kgCO 2 eq where oversized screenings of compost is converted to biochar at an off-site facility. However, direct conversion of the oversized organic waste to biochar, without composting, showed reduced global warming impact of 56 kgCO 2 eq, and is thus the most favourable scenario to limit climate impacts of this fraction of organic garden waste. However, among 18 environmental impact indicators studied, eight indicators were either not influenced or did not significantly increase by transport distance to an off-site pyrolysis facility, while the magnitude of 10 impact indicators increased with transport distance. The insights and methodologies presented in this study hold global relevance, based on an actual case study in regional Australia, offering valuable recommendations for sustainable waste management practices and establishing biochar as a carbon-neutral or carbon-negative solution. The findings contribute to existing waste management knowledge and provide guidance for accessible carbon dioxide removal and soil carbon sequestration technologies. [Display omitted] • A comprehensive LCA for valorisation of garden organics was conducted. • Direct conversion of garden organics to biochar showed least potential environmental impacts. • Biochar provides opportunities for avoided, reduced, and removed carbon from atmosphere. • Maximum transport distance has been identified for individual impact categories. [ABSTRACT FROM AUTHOR]

The assessment of soil health and the determination of carbon stability in soils are current challenges that have gained momentum through initiatives at national as well as international scales. However, inferring universally valid soil health parameters that are directly linked to carbon permanence remains challenging. Our aim was to evaluate the potential of simultaneous thermal analysis (STA) for an improved monitoring of soil health advances in the context of carbon farming strategies. For this purpose, an on-farm comparison of soil health in ten conservation agricultural systems with adjacent conventional farms was performed based on STA and thermal measures were related to key biological and physical indicators for monitoring soil functions. Using an autocorrelation-based approach, we identified independent thermal indicators, revealing that carbon farming efforts predominantly increased labile soil organic matter fractions in the range of 300–400 ° C , while thermally more recalcitrant fractions did not respond to farming system transformation. Similarly, most soil health indicators revealed highest correlation with temperature ranges of mass loss of labile organic matter fractions. The relation of STA with commonly used soil health indicators was highest for soil organic carbon (SOC, r = 0. 971) and total nitrogen (TN, r = 0. 981). However, also inference on microbial activity parameters such as dimethylsulfoxid reduction, microbial biomass carbon and substrate-induced respiration could be demonstrated with r > 0. 663. The results thus highlight key temperature ranges of organic matter stability for future soil monitoring tasks of climate change mitigation potentials of carbon farming and related advances in soil health. • We tested simultaneous thermal analysis (STA) as a tool for soil health assessment. • We did so by an on-farm comparison of conventional and conservation farming systems. • Improvements by conservation farming were mainly detected for labile C fractions. • Specific STA mass loss ranges correlated well with several soil health indicators. [ABSTRACT FROM AUTHOR]

Effective municipal solid waste (MSW) management is a crucial component for sustainable cities, as inefficient waste disposal contributes to the release of about a billion tons of CO 2 -eq in greenhouse gases (GHG) annually. With escalating global waste generation, there is an untapped opportunity to integrate carbon dioxide removal (CDR) technologies into existing MSW management processes. This review explores current research on utilizing MSW for CDR, emphasizing its potential for both energy generation and carbon sequestration. The investigation covers three waste management practices: landfilling, waste-to-energy (WtE), and biochar production, revealing two paths for carbon sequestration. First, MSW serves as a feedstock in bioenergy with carbon capture and storage (BECCS), acting as a carbon-neutral resource that avoids fossil fuel and energy crop use, reducing GHG emissions and generating value through energy production. Second, direct storage of organic MSW and its derivatives, like biochar, in various carbon sinks allows for extended sequestration, offering a comprehensive approach to address the challenges of waste management and climate change mitigation. Moreover, this review advocates for an extended exploration into several subjects including in-depth analysis of waste, research on MSW-derived biochar recalcitrance across different carbon sinks, and understanding the symbiotic connections with GHG-emitting sectors like agriculture and energy. Finally, this review emphasizes the necessity of conducting life-cycle assessment studies to fully discern the benefits and assess the impacts of any future endeavors exploring the role of MSW in carbon sequestration. [Display omitted] • Municipal solid waste (MSW) is an untapped resource for carbon dioxide removal. • Three strategies to utilize MSW for CO 2 removal include landfilling, waste-to-energy, and biochar production. • Carbon sequestration is achieved through MSW-burial and energy recovery with CCS. • Auditing carbon emissions and LCA are necessary to illuminate the impacts of MSW. [ABSTRACT FROM AUTHOR]

Carbon neutrality strategies have a significant role in climate mitigation efforts. As global concerns regarding climate change continue to increase, achieving carbon neutrality has emerged as a paramount objective for reducing greenhouse gas emissions and limiting the adverse impacts of anthropogenic activities on the environment. This research investigates a wide range of scholarly works to conduct an in-depth analysis and synthesis of the relevant information about carbon neutrality strategies. The review introduces carbon neutrality principles and terminologies, highlighting their importance in climate mitigation. It then proceeds to explore the wide range of strategies employed across different sectors and industries, investigating their effectiveness, scalability, and potential challenges. A multidimensional analysis contrasts the United States Nationally Determined Contributions pathway 2023, China's Nationally Determined contributions 2023, and the EU Directive 2023/2413, assessing their economic, environmental, political, and social impacts. The study evaluates strategies' effectiveness, scalability, and innovation for transitioning to a sustainable, low-carbon future. It fills a gap by analyzing global approaches across the US, China, and the EU, which account for about 50% of the world's total GHG emissions. It evaluates the novel application of diverse strategies, from renewable energy transitions to innovative policy measures, highlighting their potential to mitigate climate change effectively. By providing a multidimensional analysis of these strategies' impacts, the research not only enhances understanding of effective carbon neutrality tactics but also underscores the importance of international cooperation in realizing a sustainable, low-carbon future. • Identifies and analyzes carbon neutrality strategies, emphasizing the need for diverse US, Chinese, and EU approaches. • Evaluate renewable energy, carbon capture, and policy tools for carbon reduction effectiveness, scalability, and innovation. • Highlights the study's novelty in synthesizing current knowledge on carbon neutrality, addressing a significant research gap. • Concludes with strategic ideas for international collaboration and policy development for low-carbon futures. [ABSTRACT FROM AUTHOR]

Small Island Developing States (SIDS) face complex socio-economic and environmental threats, making them particularly vulnerable to climate change. Blue Carbon (BC) ecosystems (mangrove forests, tidal marshes, and seagrass meadows) provide climate regulation services by sequestering and storing carbon, presenting an opportunity for SIDS to address climate change and implement Paris Agreement commitments in their Covid-19 recovery. BC habitat decline not only reduces carbon sequestration benefits provided, but can also result in sediment disturbance and the release of previously stored carbon back into the atmosphere. In this work, a scenario analysis informed by a stakeholder workshop and scientific and socio-economic expectations is used to assess the economic importance of Grenada's BC (mangroves and seagrasses) over the next 10, 25 and 50 years. Our findings indicate that sequestration benefits are severely diminished under Business-as-Usual habitat loss, but still marginally outweigh losses from carbon emissions, with overall welfare gains of US$0.5–1.9 million over 50 years. To stimulate economic recovery post-pandemic, stakeholders anticipated a realistic scenario of increased habitat decline resulting in overall losses of US$5.4–19.4 million in the next 50 years. However, if ecosystems are maintained, overall carbon benefits could reach US$10.7 million, while a 20% increase in mangroves over the next 25 years provides benefits reaching US$11.1 million between 2020 and 2070. These results demonstrate a significant increase in value when BC ecosystems are maintained and not disturbed, preventing the release of previously stored carbon and enhancing sequestration capacity. Restoration benefits are marginal, compared to conservation, supporting claims that conservation is more cost effective. • A scenario analysis is used to value Grenada's BC climate mitigation service. • Maintaining BC extents retains sequestration worth up to $10.7million over 50 years. • BAU habitat loss lowers sequestration and releases stored carbon, reducing benefits. • More severe habitat declines result in welfare losses up to US$19.4million by 2070. • Integrating BC into SIDS' Paris Agreement commitments can enrich climate mitigation. [ABSTRACT FROM AUTHOR]

Bauxite residue or Red Mud (RM) is a by-product from alumina refineries. It has a high pH of 11–13 and accumulates globally at 200 million tons yearly, totalling about 4.6 billion tons. Being an alkaline anthropogenic geomaterial, its adsorption properties and reactivity with acidic gases make it a potential sink for CO 2 and SO X emissions from the aluminium industry. It offers both research challenges and opportunities for its utilisation at an industrial scale. In particular, carbon capture and mineralisation (CCM) within RM has been demonstrated in situ and waste disposal areas through direct air trapping of atmospheric CO 2. The RM-CO 2 system is also operated in ex-situ conditions in various physical states, such as powder, wet cakes, and slurry, with yields of carbonates as CaCO 3 , Na 2 CO 3 , and FeCO 3. Our contribution as a review illuminates significant advancements made and challenges for enhancing the mineral carbonation potential of RM, thereby delineating areas necessitating further exploration. Although, researchers have primarily focused on accelerating the CCM process in RM through slurry carbonation techniques. Recent advancements in filter press technologies have favoured soda recycling and wet cake disposal of RM, creating artificial mountains of RM stacks. With changing disposal trends for RM, it is vital to understand the mechanisms that govern long-term atmospheric CO 2 trapping in RM disposal areas. Recent investigations of techniques, hydrothermal treatment and dual-stage calcification-carbonation methods have expanded the domain of CCM in RM. Given the global need to reduce CO 2 emissions, CCM using RM does offer promising insights on account of its unique physicochemical and mineralogical properties. We, although presume that RM alone will not fully offset the CO 2 emissions of the aluminium industry. Enhanced weathering and mineral carbonation could reduce over 50% of refinery emissions. Uncertainties persist regarding methods of CO 2 sequestration potential and techno-economic feasibility when tested at a field scale. Moreover, contrasting results are revealed, primarily regarding changing disposal trends, variabilities in mineralogy, and limited knowledge of micro-mechanisms of the CCM process in RM. This work elucidates existing knowledge on synthesising CO 2 mineralisation, pathways, and mechanisms under various states associated with leveraging RM as a significant carbon sink in current and future climate change mitigation efforts. [Display omitted] • Illustrates RM mineral carbonation process and mechanistic models for CCM methods (slurry, semi-dry, atmospheric). • CCM potential is studied along with mechanisms using hydrothermal treatment, siderite formation and calcification-carbonation method. • Guidelines for RM sample extraction methods based on its physico-geochemical changes in BRDA with atmospheric CO 2. • Current and future research directions are discussed. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of amine-impregnated polymer aerogels for CO 2 capture represents a groundbreaking advancement in combating the urgent challenges of carbon dioxide (CO 2) emissions and climate change mitigation. The traditional way of synthesizing aerogels for CO 2 capture is to use a one-step gelation process without functionalizing the aerogel, which, to some extent, has low CO 2 capture capacity and kinetics. This study finds a method of synthesizing the functionalized aerogel, which has high CO 2 adsorption capacity, faster kinetic, and is more stable. The polymer aerogel was developed using an oil-water emulsion polymerization method, followed by freeze-drying. It was impregnated with a mono-ethanolamine (MEA) solution to enhance CO 2 adsorption. The performance of the amine-impregnated poly (AAm-co-AAc) aerogels was tested in a continuous adsorption column filled with aerogel. The adsorption results showed the amine-impregnated aerogels having an amine equilibrium uptake value of 40% had significantly improved CO 2 capture capacity up to 2.34 mmole g−1 at 1 bar pressure, 25 °C reaction temperature, and 10 ml/min flow rate. The polymeric aerogel has a very fast adsorption rate, as it can capture 90% of its maximum capacity within just 10 minutes. Then the kinetic data of the CO 2 adsorption was modelled and found to best fit on both pseudo-1st and 2nd-order kinetic models, proposing that the adsorption mechanism on aerogel was controlled by surface diffusion and chemisorption. Furthermore, the isotherm data were evaluated and observed to be best represented by the Langmuir isotherm model, suggesting monolayer formation on the aerogel. After five adsorption-desorption cycles, the amine impregnated poly (AAm-co-AAc) aerogel was able to preserve the initial capacity without a significant decrease. These findings underscore the immense ability of amine-impregnated poly (AAm-co-AAc) aerogels as highly efficient adsorbents for CO 2 capture, thus offering a speedy adsorption process and showing stable regeneration capacity, thereby exhibiting greater industrial application potential. [Display omitted] • An emulsion polymerization method was used to synthesize aerogels for CO 2 capture capacity. • The morphology of the aerogel is fibrous, contributing to its high amine uptake. • Its CO 2 adsorption capacity is up to 2.34 mmole g−1 at 25°C, and regeneration stability is five cycles. • The aerogel exhibits a rapid adsorption rate, capturing 90% of its capacity within 10 minutes. [ABSTRACT FROM AUTHOR]

The Andalusian olive grove in South Spain is employed as a case study to assess the environmental and economic effects of the green architecture (eco-schemes) of the Common Agricultural Policy in relation to low carbon agriculture under different soil management policy scenarios to support more efficient agri-environmental policy making. To do so, we adopted a multidisciplinary approach in which we used: (i) an integrated modelling framework comprising geographic information systems (GIS); (ii) the RothC model; and (iii) a cost-benefit analysis. Results show that eco-schemes provide a significant increase of soil organic carbon (SOC) relative to cross-compliance. Practices involving vegetation covers are more efficient than using pruning residues as mulching. SOC accumulation increases rapidly in the first five-ten years to slow down afterwards. The cost-benefit ratios of eco-schemes policy implementation are higher than one when only SOC is considered. Nonetheless, the inclusion of additional co-benefits has the potential to invert this scenario and enhance policy efficacy. Various insights on optimizing the design and application of eco-scheme efficiency are provided. • The new eco-schemes CAP instrument proposed for woody crops contribute to increase SOC • Mowing cover crops leads to the highest SOC stocks, whereas pruning debris maintains SOC stocks. • Tillage and no-tillage with bare soil systems lead to a significant depletion of SOC stocks. • The economic benefits of eco-schemes would not off-set the costs borne by public authority • Environmental externalities are key to reach the profitability of the policy instruments. [ABSTRACT FROM AUTHOR]

Existing assessments of climate mitigation technologies, like carbon capture utilisation and storage (CCUS), often rely on life cycle assessments (LCA), which are helpful for quantification but may not always be the most complete tools for decision-making. The novel contribution of this study is to provide the first application of a consequential carbon accounting approach, presented as a time-series analysis, to measure the system-wide change in emissions from CCUS linked to CO 2 -enhanced oil recovery. This method includes emissions from marginal oil production, a variable typically excluded in other LCA methods. The method was applied to a hypothetical CCUS project in Mexico to understand critical factors determining whether such an intervention can effectively contribute to emissions reduction in alignment with net-zero goals. Four intervention scenarios were assessed, comparing two distinct CO 2 injection strategies in oil reservoirs (water alternating gas and continuous gas injection) and two energy policy scenarios (current and sustainability). The findings suggest that the energy grid's role in overall emissions is relatively minor, with only a ∼2% difference between the compared scenarios, in contrast, the injection strategy has a significant impact on emissions. Scenarios 1 and 3 report a total change in emissions of −28.39 and −29.87MtCO 2 e, and scenarios 2 and 4 account for −19.63 and −21.22MtCO 2 e, respectively. The results highlight the importance of conducting system-wide analysis and comparing different scenarios to identify the critical components that drive changes in emissions and, therefore, support decision-making and project planning. • Consequential carbon accounting quantifies the system-wide change caused by CCUS. • A time-series provides decision-relevant information on climate change mitigation. • Market-mediated effects are highly relevant for CCUS projects. • CCUS is not consistent with net zero due to as remaining emissions. [ABSTRACT FROM AUTHOR]

• The 57.00% of the Yangtze River Economic Belt area exhibited a significant increase in annual NPP. • The response of NPP on climate factors was nonlinear, with greater sensitivity to temperature. • The impact of topographic factors on NPP changes had a threshold effect. Net primary productivity (NPP) of terrestrial ecosystems serves as a crucial carbon sink, playing a significant role in mitigating climate change. This study, focusing on the Yangtze River Economic Belt (YREB), a key area for both economic development and ecological conservation in China, evaluates the temporal and spatial changes in regional NPP and its responses to climatic factors against the backdrop of global change. Utilizing long-term NPP and meteorological grid data from 1981 to 2017, we analyzed the annual change patterns of NPP and its linear and nonlinear responses to climatic factors using copula functions. Our findings indicate that 57.00 % of the YREB has experienced a significant increase in NPP, with the most substantial decreases observed in Shanghai and its surrounding areas (P < 0.05). Temperature emerged as the primary climatic driver, positively correlating with NPP changes in over half of the study area (P < 0.05). Moreover, the nonlinear response of NPP to temperature and precipitation underscores the complex interactions between these factors, revealing a sensitivity to temperature variations that surpasses that to precipitation. The study also highlights the influence of solar radiation and topographic factors, with a significant positive correlation between NPP and solar radiation observed in 15.85 % of the area (P < 0.05). The practical significance of these findings lies in their implications for regional ecological management and climate resilience strategies. The positive correlation between temperature and NPP underscores the potential for targeted temperature management to optimize carbon sequestration across the YREB. Furthermore, the identified nonlinear responses and the role of solar radiation and topography in influencing NPP offer valuable insights for the formulation of adaptive strategies that enhance ecosystem productivity and contribute to achieving carbon neutrality goals. By elucidating the dynamics of NPP in response to a range of environmental factors, this study provides a foundation for informed decision-making in ecological conservation and climate change mitigation efforts within the YREB and similar regions globally. [ABSTRACT FROM AUTHOR]

Boreal forests are often managed to maximize wood production, but other goals, among which climate change mitigation, are increasingly important. Hence, it is necessary to examine synergies and trade-offs between forest production and its potential for carbon sequestration and climate change mitigation in forest stands. To this aim, we develop a novel mass-balanced process-based compartmental model that allows following the carbon path from its photosynthetic fixation until its return to the atmosphere by autotrophic or heterotrophic respiration, or by being burnt as wood product. Following carbon in the system allows to account for how long forest ecosystems and wood products retain carbon away from the atmosphere (i.e., the carbon transit time). As example, we apply the model to four management scenarios, i.e., mixed-aged pine, even-aged pine, even-aged spruce, and even-aged mixed forest, and contrast metrics of performance relative to wood production, carbon sequestration, and climate change mitigation potential. While at the end of an 80 yr rotation the even-aged forests held up to 31% more carbon than the mixed-aged forest, the mixed-aged forest was superior during almost the entire rotation when factoring in the carbon retention time away from the atmosphere, i.e., in terms of climate change mitigation potential. Importantly, scenarios that maximize production or amount of carbon stored in the ecosystems are not necessarily the most beneficial for carbon retention away from the atmosphere. These results underline the importance of considering carbon transit time when evaluating forest management options for potential climate change mitigation. [Display omitted] • We evaluate wood production and climate change mitigation potential of boreal forests. • We combine an ecophysiological growth model with forest inventory tree allometries. • Higher carbon sequestration does not ensure higher climate change mitigation potential. • Potential climate change mitigation depends on carbon time away from the atmosphere. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hedgerows and adjacent croplands at 23 sites across Germany were sampled. • Under hedgerows, 36 ± 49 % more soil organic carbon (SOC) was stored compared to cropland. • 41 % of absolute SOC stock increase was found in subsoil below 30 cm soil depth. • SOC stocks were also increased along the transect from the hedgerow to the cropland. • Planting hedgerows on 3 % of German cropland could increase SOC stocks by 13 Tg C. Carbon dioxide removal strategies are becoming increasingly important as a fundamental component of comprehensive climate policies. One strategy to increase carbon (C) sinks is the integration of hedgerows into agricultural landscapes. Besides additional C storage in above-ground and below-ground hedgerow biomass, the establishment of hedgerows has the potential to increase soil organic carbon (SOC) stocks. However, empirical data regarding the magnitude of SOC accrual with hedgerow establishment are still limited. We sampled 23 sites across Germany in a paired-plot approach with the aim of estimating SOC stock change with hedgerow establishment on cropland. At 21 sites, SOC stocks were higher beneath hedgerows than in the reference cropland. On average, SOC stock accrual was 29 ± 22 Mg ha−1 (36 ± 49 %) in 0–100 cm soil depth. SOC stocks were significantly different in both topsoil and subsoil. Subsoils below 30 cm depth contributed 41 % (12 ± 17 Mg C ha−1) of the total SOC stock change, stressing the importance of subsoil SOC for the total SOC stocks of hedgerow systems. The positive effect of hedgerows on SOC stocks extended laterally beyond the hedgerow area itself. SOC stock in the grassy hedgerow edge also increased significantly by 22 ± 22 Mg C ha−1 (28 ± 30 %) and SOC stock in the cropland directly adjacent to the hedgerow were 9 ± 19 Mg C ha−1 (12 ± 25 %) higher than in the reference cropland. Particularly high C stock differences between hedgerows and reference cropland soils were found in old hedgerows (>200 years) planted on hedgebanks, which are typically found in northern Germany. Our study confirmed that SOC stocks increase with hedgerow establishment on cropland throughout the whole soil profile. If hedgerows were to be established on 3 % of Germany's cropland area, SOC stocks would increase by 13 Tg C equivalent 48 Mio. t CO 2 , highlighting that hedgerows are a promising and multi-functional climate change mitigation option. [ABSTRACT FROM AUTHOR]

• A CGE model elaborately depicting six CCS technologies was developed. • Impacts of four CCS incentive scenarios on decarbonization pathways were simulated. • CCS can sequester 960 ∼ 1,604 MtCO 2 annually in China by 2060 with policy incentives. • CCS incentives can reduce China's future primary energy demand by 7.7 ∼ 17.4 %. • CCS incentives can increase GDP by 5.64 ∼ 6.59 % compared to no policy scenario. Carbon capture and storage (CCS) technology, considered as a pivotal tool in mitigating climate change within the fossil energy system, particularly in China, has experienced slower development than expected. The exploration of direct incentive policies to facilitate its growth remains relatively underdeveloped. This study developed a hybrid dynamic computable general equilibrium (CGE) model to simulate the substantial impacts of CCS incentive policies on China within the context of carbon neutrality target. Two potential incentive policies, carbon emission trading system (ETS) and 45Q tax credit, were simulated, with different sectoral coverage. The results indicate that CCS technologies can reduce carbon emissions by 960 ∼ 1,604 MtCO 2 annually by 2060 through the strategic implementation of these incentive policies. The 45Q tax credit demonstrates its effectiveness in promoting early-stage research and development (R&D) and demonstration of CCS, while the ETS policy facilitates the commercial development of CCS in the later stage of development. By 2060, the implementation of CCS incentive policies could potentially result in 7.7 ∼ 17.4 % reduction in China's primary energy consumption, 71.2 ∼ 82.7 % decrease in the carbon price of ETS and 5.64 ∼ 6.59 % increase in the GDP compared with the no-policy scenario. In addition, the sectoral output in various sectors and the welfare of urban and rural households also increase. This paper provides an important reference for the realization of China's carbon neutrality goal and the model framework can be applied to other countries. [ABSTRACT FROM AUTHOR]

Fire and overgrazing reduce aboveground biomass, leading to land degradation and potential impacts on soil organic carbon (SOC) and total nitrogen (TN) dynamics. However, empirical data are lacking on how prescribed burning and livestock exclusion impact SOC in the long-term. Here we analyse the effects of 19 years of prescribed annual burning and livestock exclusion on tree density, SOC and TN concentrations in the Sudanian savanna ecoregion at two sites (Tiogo and Laba) in Burkina Faso. Results revealed that neither livestock exclusion nor prescribed burning had significant impact on SOC and TN concentrations. The results at both sites indicate that 19 years of livestock and fire exclusion did not result in a significant increase in tree density compared to grazing and annual prescribed burning. The overall mean (± SEM) of SOC stocks in the 0–50 cm depth increment in the unburnt (53.5 ± 4.7 Mg C ha−1) and annually burnt (56.4 ± 4.3 Mg C ha−1) plots at Tiogo were not statistically different. Similarly, at Laba there was no significant difference between the corresponding figures in the unburnt (37.9 ± 2.6 Mg ha−1) and in the annually burnt plots (38.6 ± 1.9 Mg ha−1). Increases in belowground inputs from root turnover may have countered changes in aboveground biomass, resulting in no net change in SOC and TN. We conclude that, contrary to our expectation and current policy recommendations, restricting burning or grazing did not result in increase in SOC stocks in this dry savanna ecosystem. [ABSTRACT FROM AUTHOR]

• Climate change threatens the carbon sink capacity of forests in Chile. • Industrial plantations do not contribute towards achieving carbon neutrality. • Wildfire emissions exceed the nationally determined contributions mitigation. • Climate actions should diversify including a wider range of nature based solutions. • Conservation and restauration of wetlands can contribute to carbon neutrality. As president of the Climate Change Conference of the Parties, Chile has advocated for developing ambitious commitments to mitigate greenhouse gas emissions to achieve carbon-neutrality by 2050. However, Chile's motivations and ambitious push to reach carbon-neutrality are complicated by a backdrop of severe drought, climate change impacts (i.e., wildfires, tree mortality), and the use of industrial plantations as a mitigation strategy. This has become more evident as widespread and severe wildfires have impacted large areas of industrial plantations, transforming the land-use, land-use change, and forestry sector from a carbon sink to a net carbon source. Consequently, Chile must diversify its climate actions to achieve carbon-neutrality. Nature-based solutions, including wetlands-peatlands and oceans, represent alternative climate actions that can be implemented to tackle greenhouse gas emissions at a national level. Diversification, however, must guarantee Chile's long-term carbon sequestration capacity without compromising the ecological functionality of biodiverse tree-less habitats and native forest ecosystems. [ABSTRACT FROM AUTHOR]

The bioeconomic potential of monopodial and sympodial bamboos is not well understood. Therefore, Net primary productivity (NPP), total biomass, carbon (C) stock, soil organic carbon (SOC), CO 2 sequestration, and bioenergy potential were studied in a sympodial Chimonocalamus griffithianus and a monopodial Phyllostachys mannii bamboo in Meghalaya, north-eastern India. P. mannii stand with mean culm density 16,877 ha−1, height 14.8 m and diameter 4.4 cm, accumulated 107.56 Mg ha−1 biomass with a total NPP of 18.83 t ha−1yr−1. It stored 50.67 Mg C ha−1 in biomass, 77.28 Mg C ha−1 in soil, and had sequestration potential of 469.58 t CO 2 ha−1. C. griffithianus stand with mean clump density 1065 ha−1, mean culm density 52,185 ha−1, height 7.19 m and diameter 3.04 cm, accumulated 67.08 Mg ha−1 biomass with a total NPP of 15.30 t ha−1 yr−1. It stored 31.30 Mg C ha−1 in biomass, 83.25 Mg C ha−1 in soil, and had sequestration potential of 420.40 t CO 2 ha−1. Matured culms (>2–3 years old) of P. manni and C. griffithianus produced 143.08–166.65 MW h and 87.13–101.48 MW h of energy per ha, respectively. Although landuse history and site characteristics of the two stands were not 100 % identical, significantly greater (p < 0.05) standing biomass, NPP, growth rate, carbon sequestration potential, and energy values of P. mannii than C. griffithianus makes the monopodial bamboo a better choice for energy plantation and climate change mitigation tool than the sympodial. • Monopodial bamboo, Phyllostachys mannii , surpasses sympodial Chimonocalamus griffithianus in bioeconomic potential. • P. mannii exhibits higher biomass, NPP, carbon sequestration, and energy values. • Comparative analysis reveals the superior suitability of monopodial bamboo for energy plantations. • Results provide valuable insights for sustainable development in India's biobased economy. • Study contributes to understanding the role of bamboos in mitigating climate change. [ABSTRACT FROM AUTHOR]

• Substitution factors for forest products for the Canadian context were developed. • Substitution factors ranging from 0.51 to 0.91 tC/tC were found. • They will lead to more accurate assessments of the forest GHG mitigation potential. • These factors will help governments to manage forest and fight climate change. Evaluating the climate change mitigation potential of the forest sector requires a holistic approach based on forest carbon (C) sequestration, C storage in harvested wood products (HWP) and substitution on markets. High uncertainty is associated with substitution factors, that express avoided fossil greenhouse gas (GHG) emissions from the use of forest-based products in replacement of GHG-intensive materials and fossil fuels. Few studies have focused on the development of substitution factors in Canada, resulting in the use of unrepresentative generic data. Here, we provide a framework to reduce uncertainties related to substitution factors for primary wood products in a Canadian context. A life cycle assessment framework is used to quantify fossil GHG emissions for a baseline and a wood-intensive scenario. For solid product substitution, we focused on the construction sector and analyzed a range of innovative wood buildings with steel and reinforced concrete as alternative materials. We found non-weighted averages of 0.80 tC/tC for sawnwood and 0.81 tC/tC for panels. For energy substitution, we analyzed cases with different specifications on biomass product, facility type and alternative fossil fuel source in non-residential heat production and biofuel transportation sectors. We found a non-weighted average of 0.80 tC/tC for non-residential heat production and 0.51 tC/tC for biofuel transportation, that can be interpreted as 0.91 tC/tC for heavy fuel oil, 0.69 tC/tC for light fuel oil and 0.68 tC/tC for natural gas substitution. These results provide a benchmark for substitution factors in Canada, to help guide forest management strategies for climate change mitigation. [ABSTRACT FROM AUTHOR]

Due to the expeditious rise in anthropogenic activities and rapid extractive pressure, protected areas in the Indian Himalayan Region (IHR) are experiencing significant losses in ecological diversity and a substantial decline in the potential for carbon sequestration and climate change mitigation. The quantification of carbon sequestration and the understanding of its corresponding economic gain/loss are crucial for raising strict preservative concerns in protected areas with rich ecological and economic values. Transitions in land use land cover (LULC) trajectories from historical to future scenarios impact the dynamics of carbon storage and sequestration in terrestrial ecosystems. The present study extends a comprehensive 40-year (1995–2035) assessment of carbon mapping (gain/loss) as well as an economic approximation of carbon sequestration in the Askot Wildlife Sanctuary (AWLS), Western Himalaya, using satellite data. This investigation presents a novel hybrid approach by infusing machine learning algorithms and a spatial-temporal technique-based MLPnn-Markov chain model for future LULC simulation with the InVEST model that incorporates carbon mapping and economic valuation. The results show that among all the land use classes, dense forest has the highest carbon density; however, it exhibits a decreasing trend from 1995 (5,695,878.41 Mg/ha) to 2035 (4,378,439.81 Mg/ha). The economic quantification of carbon sequestration was performed by applying sensitivity analysis combined with different carbon prices and discount rates from 2020 to 2035. The observed outcomes reveal significant economic losses due to rapid forest cover decline, as indicated by a negative net present value (NPV) ranging from a minimum of ∼US$ -8 million to a maximum of ∼US$ -53 million. This study develops a valuable database by providing evidence-based decision-making and guidance for the sustainable preservation of ecosystems in the Western Himalayas and similar regions worldwide, where forest carbon sequestration is of paramount importance. The findings of the study suggest sound provisions for the conservation of forested landscapes and the development of efficient voluntary and regulatory carbon trading markets to achieve stability in forest carbon stocks. In doing so, this interdisciplinary approach addresses the growing imperative of integrating ecological and economic aspects in the context of biodiversity conservation and climate change mitigation. • Carbon sequestration in forests and across the landscape is performed and compared. • Remote sensing and machine learning techniques are executed for LULC simulation. • Carbon mapping is carried out in InVEST model. • Both country-level and international carbon prices are used for economic accounting. • Decline in forest cover encounters huge economic losses. [ABSTRACT FROM AUTHOR]

While carbon sequestration is significant to achieve the net zero and plays an important role in climate change mitigation, urbanization-led land use land cover (LULC) changes are causing significant impacts on the carbon stocks of terrestrial ecosystems. Despite rapid urbanization in Pakistan, previous studies focus solely on localized areas without documenting the influence of urbanization on carbon stock. Hence, insights regarding the carbon storage dynamics (CSD) in response to LULC changes become essential to drive informed decisions and policies. In this context, we leverage high-resolution (30 m) remote sensing data to evaluate and map the grid-level spatial-temporal interactions between urbanization and CSD at the national scale in Pakistan during 1990–2020. To do so, multi-sensor earth observation data are retrieved and processed using the Google Earth Engine and the Integrated Valuation of Ecosystem Services and Tradeoffs models. Our findings indicate that urban areas have expanded exponentially (an increase of ∼1040%), resulting in reduced carbon storage (a decrease of ∼ − 5%). Major cities (e.g., Karachi, Lahore, Faisalabad) showed less urban sprawl while emerging cities (e.g., Rawalpindi and Peshawar) demonstrated higher urban sprawl, primarily due to shifting patterns from rangeland (∼47%) and agriculture (∼35%) to built-up class. Though some afforestation projects have increased forest carbon stocks in the northern region, there is a large north-south spatial heterogeneity in carbon storage loss across Pakistan. The presented high-resolution mapping of CSD over the past three decades advances our understanding of where and how much urbanization has influenced carbon sequestration, nationally. Considering the results, this study emphasizes the need for policies and management approaches that support sustainable urbanization, which does not compromise carbon pools in the country. • Grid level impact of LULC transition and its influence on CSD is mapped. • Transition from green cover to built-up areas led to reduced carbon storage. • Sustainable land management is imperative to maintain carbon storage capacity. [ABSTRACT FROM AUTHOR]

In the face of escalating global climate challenges, effective carbon dioxide (CO₂) capture techniques remain at the forefront of mitigating anthropogenic greenhouse gas emissions. This comprehensive review elucidates the latest advancements in CO₂ capture, emphasizing two predominant methodologies: absorption and adsorption. We delve into the mechanisms underlying each process, highlighting the novel materials and technologies that have emerged over recent years. For absorption, the focus is placed on the material design strategy, and identifying new materials in the class of amines, ionic liquids (ILs) and nanofluids for enhanced CO 2 capture capacities and reduced energy requirements. In the realm of adsorption, the synthesis of innovative adsorbents, such as metal organic framework (MOF), organic polymers, inorganic adsorbents, silicon-based adsorbents, and biochar and byproducts from biomass with superior selectivity and stability, is explored. Additionally, the review addresses the challenges associated with each method, offering insights into potential avenues for further research. By providing a holistic overview of the current landscape of CO₂ capture, this article serves as a pivotal resource for researchers and industry professionals aiming to advance sustainable solutions to combat climate change. [Display omitted] • Absorption and adsorption materials are at the forefront of CO 2 capture technologies. • Ionic-liquids and nanofluids can be comparable to amines with improvements in scalability and stability. • Biomass byproducts as adsorbents offers a sustainable solution to CO 2 capture. [ABSTRACT FROM AUTHOR]

• Solutions to the climate crisis are not ahistorical. • Both social and technical processes explain their rise (or fall) on the agenda. • Thinking about ocean CDR closely co-evolved with scientific understandings of global climate change. • Ocean CDR methods have followed cycles of hype, controversy and disappointment. • Key sociotechnical configurations and narrative changes explain the new hype around ocean CDR. While the ocean has long been portrayed as a victim of climate change, threatened by ocean warming and acidification, it is now increasingly framed as a key solution to the climate crisis. In particular, the promising carbon sequestration potential of the ocean is being emphasised. In this paper, we seek to historicise the practices, discourses and actors that have constructed the ocean as a climate change solution space. We conceptualise the debate about the mitigation potential of the ocean as a contested site of governance, where varying actors form alliances and different sociotechnical narratives about climate action play out. Using an innovative quali-quantitative methodology which combines scientometrics with document analysis, observational fieldwork, and interviews, we outline three historical phases in the history of ocean carbon sequestration that follow recurring cycles of hype, controversy and disappointment. We argue that the most recent hype around ocean carbon sequestration was not triggered by a technological breakthrough or a reduction in scientific uncertainty, but by new socio-technical configurations and coalitions. We conclude by showing that how climate change solutions are put on the agenda and become legitimised is both a scientific and political process, linked to how science frames the climate crisis, and ultimately, its governance. [ABSTRACT FROM AUTHOR]

Direct air capture (DAC) technology plays a crucial role in mitigating the effects of global warming by capturing carbon dioxide (CO 2) directly from the atmosphere. A significant technical challenge for DAC is its high thermal energy consumption, which results in an unacceptable overall cost (600 $ t CO 2 – 1). The combination of a high-temperature heat pump (HTHP) and DAC system offers a substantial reduction in thermal energy consumption, decreased reliance on renewable energy sources, and enhanced DAC system flexibility. This study presents three distinct thermal integration strategies that combine an HTHP with solid adsorbent-based DAC and verifies their effectiveness in reducing energy consumption and CO 2 emissions compared to a traditional DAC system. Among them, the deeply integrated DAC-HTHP system (I-DAC) exploits low-grade adsorption heat and waste heat, providing direct heating and cooling energy to the DAC system via refrigerant condensation and evaporation processes. Simulation results indicate that the I-DAC system achieves an extremely low operating energy consumption of 2.77 GJ t CO 2 – 1 , representing a 69.5% reduction than traditional DAC under the same conditions. Consequently, the I-DAC offers a cost-effective (32.0–46.2 $ t CO 2 – 1) negative emission solution. We also demonstrate that the I-DAC is promising for wide application in cities to recycle waste heat and remove CO 2 from the air. The comprehensive implementation of the I-DAC in 105 cities could yield a net annual productivity of 980 MtCO 2. • Proposed a deeply thermal integrated DAC system (I-DAC) with waste heat recovery heat pump. • I-DAC achieved a 69.5% reduction in specific energy consumption compared to base-DAC. • I-DAC offers a cost-effective and scalable negative emission solution for climate change mitigation. • Successful implementation of I-DAC in 105 cities could yield a net annual capture capacity of 980 MtCO 2 by 2050. • Highlights the potential of I-DAC to recycle waste heat and remove CO 2 from the air, with policy implications [ABSTRACT FROM AUTHOR]

Bioenergy with carbon capture and storage (BECCS) is regarded as a crucial negative emission technology (NET) in many prospective climate change mitigation scenarios that limit global warming below 2 °C. However, there is still insufficient understanding of the overall life cycle environmental performance of different BECCS configurations. Despite the fact that BECCS entails many technological combinations, the technology is still regarded as a single "black box" technology in most climate scenarios. This study presents a critical review of life cycle assessment (LCA) on a wide range of BECCS options: biomass direct-fired power generation, biomass gasification power generation, bio-hydrogen production, biomass application in industry sectors and other biomass conversion processes, such as pyrolysis and fermentation. It is evident from the review that the biomass direct-fired and gasification power plant with a 100% biomass firing ratio and the gasification-based bio-hydrogen processes have a strong potential to achieve negative emissions. However, the net negative life cycle emissions range widely among studies for each configuration due to variations in technology, LCA methodology and assumptions. Additionally, there is an insufficient assessment of comprehensive environmental impacts for BECCS systems other than GWP, making it still unclear about the trade-offs between the benefit from climate change mitigation and potential negative impacts. Main recommendations for improving LCA on BECCS include developing a generalized guideline and standardization for BECCS LCA, conducting LCAs with comprehensive impact categories, focusing on BECCS configurations being overlooked, considering the impact of land use change and the global warming potential of biomass, and extending LCA in both temporal and spatial dimension. [Display omitted] • Systematically review of life cycle assessment on BECCS systems. • Detailed review on various biomass conversion technologies. • Net negative life cycle emissions range widely among studies. • Insufficient studies of some biomass conversion pathways. • Insufficient studies on multi-environmental environment impact categories. [ABSTRACT FROM AUTHOR]

• Six management strategies are proposed globally following farmland abandonment. • A combination of strategies achieves multiple rural development goals. • Combining passive and active management can maximize soil carbon sequestration. • Abandoned agricultural lands are potential resources for climate change mitigation. The widespread historical and ongoing abandonment of agricultural lands worldwide presents important opportunities for promoting climate change mitigation through carbon sequestration. The default management outcome of abandonment is natural regeneration through ecological succession. However, several different management strategies and new land uses for abandoned agricultural lands have been recommended by the scientific community in recent years. This paper reviews the foremost proposed strategies and compares their soil carbon sequestration potentials. Six major categories have been proposed globally. Each proposal has positive and negative outcomes depending on site-specific factors and management objectives. Accordingly, no single strategy is ideal in all scenarios and a combination of strategies addresses multiple rural development goals concurrently. A combination of passive and active management techniques is the most effective approach for maximizing soil carbon sequestration over large geographic scales, while other strategies can be designed to also promote low-carbon land use practices and fossil fuel substitution. The implications of each proposal highlighted here demonstrates the positive role that abandoned agricultural lands can serve in climate change mitigation efforts, supporting policymakers tasked with planning the future of regions undergoing abandonment. [ABSTRACT FROM AUTHOR]

• Ecosystem services is a dominant paradigm in mangrove research and policy. • We consider how the flagship species paradigm can aid mangrove conservation. • Many charismatic megafauna have been observed in mangroves around the world. • These could be used to raise awareness, funding, and leverage upon existing policies. • We demonstrate how conservation paradigms can complement and synergize each other. The flagship species paradigm (FSP) involves the selection of a species to strategically front conservation efforts and marketing campaigns. Chosen species are often charismatic megafauna: large animals with high public appeal that – in many ecosystems – receive considerable research attention and policy coverage. However, one ecosystem in which this trend is starkly reversed is the mangrove forest, where FSP approaches are rare due to under-acknowledgment or data deficiencies regarding their larger fauna. Instead, mangrove conservation has strongly embraced the ecosystem services paradigm (ESP) since these forests provide many benefits to society such as fisheries provision, coastal protection, and climate change mitigation via blue carbon sequestration. In this article, literature searches reveal that charismatic megafauna – including tigers, sloths, lemurs, proboscis monkeys, manatees, dolphins, sea turtles, crocodiles and sawfish – are severely under-represented in mangrove research, relative to their benthic invertebrates such as crabs, shrimp, and bivalves, explaining why the FSP remains underutilized for mangroves. We further reveal that many candidate flagships species may occur – permanently or periodically – in mangrove habitats around the world, indicating the FSP could have widespread applicability for mangrove conservation. Leveraging upon these findings, we highlight how the FSP can complement, or be integrated with, the ESP in the context of awareness raising, conservation finance, and policy (e.g. Ramsar Convention). We advise that socio-ecological settings, governance systems, and drivers of mangrove deforestation should be considered when designing flagship campaigns to support the protection of these vital wetlands. [ABSTRACT FROM AUTHOR]

Rapid climate change mitigation requires carbon sequestration in addition to greenhouse gas emission reductions. Agriculture may have a high potential for carbon sequestration due to improved practices. However, it is not known how the global warming impacts of crop production could be mitigated especially within an agricultural system. The aim of this study is to evaluate possibilities to neutralize global warming impacts in crop production using biochar produced from side flows and buffer zone biomass. A life cycle assessment methodology is utilized in this research for oat production in the boreal climate zone. Global warming impact reductions are compared for three different side flow utilization options. Traditionally, side flows have been utilized in energy or fodder production, and these options are compared to biochar production at a system level. The potential to use buffer zone biomass for biochar production is also studied. Willow has been selected as a biomass source in buffer zones. Oat production leads to greenhouse gas emissions especially due to the use of fossil and mineral fertilizers in cultivation and heat energy, electricity and fuels in various process phases. The production of one metric ton of oat flakes from cradle to gate generates 700 kg of CO 2 eq emissions. Biochar and energy production from side flows enables a greater reduction in global warming impacts than the feed use of side flows. Buffer zones in willow biomass and biochar production may enable the full neutralization of the global warming potential of oat production within an agricultural system. Further research with actual measurements is required especially on biochar impacts on soil emissions such as N 2 O. This research shows that it could be possible to neutralize global warming impacts from crop production using available technologies and available biomass in agricultural systems. A framework is created for carbon neutral crop production using side flows and buffer zone biomass through biochar. • Global warming potential of oat production is studied using LCA methodology. • Oat flakes production generates emissions of 700 kgCO 2eq t−1. • Side flow use for biochar production leads to the lowest overall GWP impacts. • Buffer zone biomass use for biochar production could mitigate the GWP impacts of oat production. [ABSTRACT FROM AUTHOR]

Highlights • LAC GHG efficiency in agricultural sector using within and across country metrics. • 5 Countries offset agriculture emissions with land-use-related carbon sequestration. • Small Caribbean island-states report the worst-case decoupling elasticity scenario. • Top decoupling countries are not equivalent to high factor productivity countries. Abstract The paper explores the relationship between production and greenhouse gas (GHG) emissions in the agricultural sector of Latin America and the Caribbean (LAC) between 1990 and 2015. By appraising how GHG emissions have changed with respect to agricultural production (elasticity), we are able to classify countries into six decoupling states. While the decoupling elasticity provides information for assessing the evolution within countries, we introduce a performance ratio for country comparison by calculating GHG emissions over agricultural production for 2015 and using the global distribution as benchmark. The information from both measurements serves to identify various country and sub regional situations. The findings illustrate that countries with performance ratios in the top 25% and under the best-case elasticity scenario (of strong decoupling) are not necessarily the same as the ones usually identified under factor productivity analyses, suggesting that environment-specific policy incentives and tools play a key role in enhancing sustainable agricultural production. Another major finding is that very few countries in the region (and worldwide) are able to offset agriculture emissions with land use-related carbon sequestration practices. Lastly, the evidence on small Caribbean island-states reporting the worst-case elasticity scenario (of strong negative decoupling) and performance ratios close to the world median, further supports the need for development plans related to climate change mitigation and adaptation in this sub region. [ABSTRACT FROM AUTHOR]

• An overview of remote sensing systems and applications in vegetation monitoring. • A review on detecting CO 2 leakage effect on vegetation using hyperspectral imaging. • Identification of major issues on distinguishing CO 2 leakage-derived plant stress. • Recommendation on an integrated remote-sensing monitoring system at CCS sites. Carbon Capture and Storage (CCS) is an emerging climate change mitigation technology which prevents carbon dioxide (CO 2) from entering the atmosphere, so as to reduce greenhouse gas emissions. Environmental monitoring in CCS sites is critical for ensuring that any CO 2 leakage and its effect on biota, especially vegetation, is detectable. It also plays an important role in creating a social license to operate and assuring the general public that the mechanisms for leak detection and remediation are in place. This review overviews current remote sensing technologies for vegetation monitoring of CCS sites/regions (with a focus on rangelands and pastures), including medium-to-high resolution satellite, aerial (both manned and unmanned aircrafts) and in situ sensors and methods. Our literature survey has pointed out that remote sensing, particularly hyperspectral sensors, can accurately detect CO 2 leakage derived effects on vegetation. It can compensate the two main drawbacks of operational systems for detecting these effects over large areas. One is the areas affected tend to be relatively small (1–15 m); and the other is symptoms in vegetation tissues tend to be similar to other stresses, such as nutrient or water deficiency. With this in mind, we have recommend that a comprehensive system should be put in place. It integrates continuous monitoring with ad-hoc detection to assess vegetation conditions in a planned CCS site. Site-based pheonocams and area-based medium-resolution satellite remote sensing sources can be used to compare any given point in time (e.g. the injection point) with the condition at the same location in the past. Before an injection commences, a baseline assessment should be conducted using the combination of high-resolution aerial hyperspectral imaging and medium-resolution long-term data from Landsat sensors. Further acquisition of high-resolution aerial imagery (ideally hyperspectral) is particularly useful following specific detected CO 2 leaking events. Aiming at bridging the gaps between research, development and implementation of CCS, this review will contribute to environmental and social impacts of sustainable energy policies, including climate change mitigation and environmental pollution reduction. [ABSTRACT FROM AUTHOR]

Abstract The Paris Agreement brings countries together in a combined effort to combat climate change and its effects. A key target is the reduction of energy related greenhouse gas emissions. Providing biogas from biomass is one option to provide renewable and less carbon intensive fuels. When upgraded to biomethane it may be a substitute for natural gas and thus may have many application pathways. Recognising this potential many European countries installed governmental support programmes to stimulate market growth over the last decade. However, most of the installed schemes in Europe are time-limited. Besides being time-limited most of the schemes include a degression of compensation over time, resulting in many having limited success over longer time frames. This study questions the feasibility of near-term business cases for biomethane plants and analyses options for making them less dependent on governmental support programmes. Currently a market potential is seen in the utilization of process carbon dioxide in carbon capture and utilization or carbon capture and storage pathways, because it is a widely available side product from biogas upgrading. Therefore, we examined three business cases for its utilization in across sectors. To answer the research question we use a previously developed biomethane market simulation model and added an extension for new business cases. Results indicate that there are specific business options in the field of 2160 m³ h−1 to 20,840 m³ h−1 that are economical feasible under certain circumstances. Highlights • Use of CO2 in the chemical industry was not economically feasible even under optimistic conditions. • Utilization of carbon dioxide from biogas upgrading offers new business options. • Production of bio-LNG is a promising business option. [ABSTRACT FROM AUTHOR]

Highlights • Projections of different biomass futures contributing to strict climate targets. • We investigate the dynamics and emissions of land and energy systems. • Achieving climate targets is contingent on use of advanced bioenergy technologies. • Land use emissions can be minimised without constraining biomass supply. • Technology development and future land use are main sensitivities. Abstract Biomass is often seen as a key component of future energy systems as it can be used for heat and electricity production, as a transport fuel, and a feedstock for chemicals. Furthermore, it can be used in combination with carbon capture and storage to provide so-called "negative emissions". At the same time, however, its production will require land, possibly impacting food security, land-based carbon stocks, and other environmental services. Thus, the strategies adopted in the supply, conversion, and use of biomass have a significant impact on its effectiveness as a climate change mitigation measure. We use the IMAGE 3.0 integrated assessment model to project three different global, long term scenarios spanning different socioeconomic futures with varying rates of population growth, economic growth, and technological change, and investigate the role of biomass in meeting strict climate targets. Using these scenarios we highlight different possibilities for biomass supply and demand, and provide insights on the requirements and challenges for the effective use of this resource as a climate change mitigation measure. The results show that in scenarios meeting the 1.5 °C target, biomass could exceed 20% of final energy consumption, or 115–180 EJ Prim /yr in 2050. Such a supply of bioenergy can only be achieved without extreme levels land use change if agricultural yields improve significantly and effective land zoning is implemented. Furthermore, the results highlight that strict mitigation targets are contingent on the availability of advanced technologies such as lignocellulosic fuels and carbon capture and storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon sequestration potential of the clay fraction. • Determination of the carbon saturation deficit of each mineral of the clay fraction. • Identification of the equation for the prediction of carbon sequestration potential. • Identification of land uses with the greatest carbon sequestration potential. The capacity of soil to sequester carbon (C) is a key process that promotes the reduction of CO 2 in the atmosphere. Soils can absorb as much as 20% of anthropogenic carbon emissions, which can contribute to mitigate climate change. This capacity relies on the organo-mineral association, which includes different minerals, Fe and Al oxides, which have a critical soil organic carbon (SOC) sorption surface. Based on an equation of the potential C saturation deficit of fine soil particles (<20 μm/silt and clay fractions) for tropical regions, this study investigated the SOC sequestration potential of the clay fraction for soils in Piracicaba region, São Paulo State, Brazil as influenced by the clay minerals. This potential was fitted to a spatial regression model for soil depths 0–20 cm and 80 to 100 cm. In the surface layer, the sequestration potential was mostly explained by the relative abundance of soil minerals (Kaolinite, Hematite, Goethite and Gibbsite) determined using vis-NIR-SWIR spectroscopy. A direct relationship was observed with Goethite and Gibbsite, indicating that low concentrations would reduce the sequestration potential. At 80 to 100 cm depth, Kaolinite and Hematite explained most variation in SOC sequestration potential. Additionally, the C associated with the mineral fraction and the C saturation potential as a function of minerals were modeled and a strong importance of hematite in the C sequestration and stabilization cycle was identified at both depths. The individual mineral contribution to SOC sequestration potential was also mapped, which identified high contributions of goethite and gibbsite for deep soil layers. The influence of land use on the carbon sequestration potential of minerals was observed, with the greatest potential being found in areas with pasture and cropping mosaics and grassland and forest mosaics, with a high presence of kaolinite and hematite. These minerals have a greater potential for carbon sequestration at greater depths and, therefore, could be critical in climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Besides being an opportunity to valorize biomass residues, biochar (i.e., the solid product of biomass pyrolysis) has many potential environmental benefits, such as climate change mitigation and reduced nutrient leaching. Even though the academic interest in biochar has increased, it is not being used at a large scale yet, mainly because of its economic infeasibility compared to fertilizers and because farmers are either unaware of or skeptical about its effects. In this paper, the economics of biochar are examined by performing a systematic review, following the guidelines of the Collaboration for Environmental Evidence. Specifically, it has been examined to which extent the production and application of biochar are yet profitable from an investor's perspective and desirable from a societal perspective. For the first time, this review investigates the extent to which previous studies have included external costs and benefits. We find that profitability and desirability of biochar production and use are highly uncertain and case-specific, depending on factors like location, feedstock, scale, pyrolysis conditions, biochar price, cultivated crop, and the potential internalization of externalities, which hampers private investment. To advance biochar development and deployment, those factors must be considered carefully for each case. Although externalities are included in the literature to some extent, the focus is mostly on external benefits rather than external costs, often focusing on its carbon sequestration potential. The inclusion of externalities in economic assessments is necessary to provide solid arguments to develop policies for the acceleration of market uptake of biochar technology. [ABSTRACT FROM AUTHOR]

• SOC sequestration beneath hedgerows continues for decades but at declining annual rates. • Shallow topsoils do not contribute to sequestration. • Hedgerow age and ammonium oxalate extractable Al (Alo) are master variables of sequestration. • Expanding hedgerows to 10% of the agricultural land (EU Biodiversity Strategy) is relevant for climate change mitigation. Hedgerows supply multiple ecosystem services in agricultural landscapes and have been advocated to provide a relevant carbon sink for climate change mitigation. Using a space-for-time approach, we investigated carbon sequestration and fractionation in soils beneath hedgerows 1 to 70 yr after planting on cultivated land in the humid continental climate of Eastern Austria. We sampled 54 pairs of hedgerow and adjacent cultivated soil volumetrically to 40 cm depth and analysed them for bulk soil (< 2 mm) mass, SOC fractions of differential stability and related soil properties. Total SOC stocks to 40 cm depth increased significantly (p < 0.05) by 34.7 ± 4.70 Mg C ha−1 to 119 ± 6.77 Mg C ha−1 beneath 31–70 yr old hedgerows, and by 15.6 ± 5.94 Mg C ha−1 to 106 ± 8.98 Mg C ha−1 beneath 1–30 yr old hedgerows. Carbon sequestration was limited to the organic and mineral topsoil layer (0–20 cm), SOC changes (ΔSOC) at 20–40 cm depth were small and insignificant (p < 0.05). Linear regression of ΔSOC on hedgerow age (1–70 yr) yields a mean SOC sequestration rate of 0.65 ± 0.10 Mg ha−1 yr−1 down to 40 cm depth. Combining our data with published work we found hedgerow age explaining ∼65 % of the variation of ΔSOC in topsoils, and ∼68 % in shallow subsoils; ΔSOC increases with hedgerow age in topsoils, but declines in subsoils. Annual sequestration rates decline with hedgerow age in both soil layers. Up to 30 years after conversion, SOC is preferably sequestered in labile particulate organic matter (POM; > 20 µm), and stabilised in the mineral-associated organic matter (MAOM; < 20 µm fraction) thereafter. In the bulk soil and MAOM fraction, SOC strongly increases with oxalate-extractable Al (Al o). We conclude that SOC sequestration beneath hedgerows offers a relevant CO 2 sequestration potential which is mainly limited to topsoils and primarily controlled by hedgerow age and Al o. [ABSTRACT FROM AUTHOR]

• Most country long-term climate strategies envision reliance on NETs. • Most countries emphasize NETs that enhance natural carbon sinks. • Few countries explicitly envision slowing down short-term mitigation measures. • Countries estimate huge carbon sink potentials despite pervasive uncertainties. • This may set in motion a spiral of delay as uncertainties are sought to be reduced. In order to address the pressing challenge of climate change, countries are now submitting long-term climate strategies to the United Nations Framework Convention on Climate Change (UNFCCC) process. These strategies include within them potential future use of 'negative emissions technologies' (NETs). NETs are interventions that remove carbon from the atmosphere, ranging from large-scale terrestrial carbon sequestration in forests, wetlands and soils, to use of carbon capture and storage technologies. We assess here how NETs are discussed in 29 long-term climate strategies, in order to ascertain the risk that including the promise of future NETs may delay the taking of short-term mitigation actions. Our analysis shows that almost all countries plan to rely on NETs, particularly enhanced use of natural carbon sinks, even as a wide array of challenges and trade-offs in doing so are highlighted. Many strategies call for improved accounting systems and market incentives in realizing future NETs. While no strategy explicitly suggests that NETs can be a substitute for short-term mitigation, most estimate substantial potential for future use of NETs even in the face of acknowledged uncertainties. This, we suggest, may have the consequence of resulting in what we describe here as 'a spiral of delay' characterized by the promise of future NET options juxtaposed with the simultaneous uncertainty around these future options. Our analysis highlights that this inter-connected delaying dynamic may be intrinsic to what we term 'governing-by-aspiration' within global climate politics, wherein the voicing of lofty future ambition risks replacing current action and accountability. [ABSTRACT FROM AUTHOR]

Agriculture represents about 11% of global anthropogenic greenhouse gas emissions (GHGe). Many climate change mitigation strategies have been evaluated in Mediterranean agroecosystems, including their soil organic carbon sequestration potential. High residue yielding old varieties could constitute a useful alternative, especially for organic farming, which lacks specific genetic material. In this study, old and modern wheat varieties were evaluated under organic (ORG) and conventional (CON) management during a 3-year field experiment under rainfed Mediterranean conditions. Field measurements of biomass components, literature emission factors, and soil organic carbon modeling were combined in an attributional Life Cycle Assessment, in order to estimate GHGe from “cradle to farm gate”. The resulting yield-based carbon footprints of old wheat varieties were significantly lower than those of modern varieties both under CON management, decreasing from 263 to 144 g CO 2 e kg −1 , and under ORG management, decreasing from 29 to −43 g CO 2 e kg −1 . Our results indicate that climate change mitigation strategies in Mediterranean rainfed cereal cropping systems should focus on diminishing GHGe from machinery and fertilizer use, and promoting carbon sequestration. The combination of organic management and old cereal varieties can constitute a promising climate change mitigation strategy in these systems, as low area-scaled GHGe of organic management are combined with enhanced carbon sequestration and a good yield performance of old varieties under these conditions. [ABSTRACT FROM AUTHOR]

Global climate change is a pressing problem caused by the accumulation of anthropogenic greenhouse gas emissions in the atmosphere. Carbon dioxide (CO 2 ) capture and storage is a promising component of a portfolio of options to stabilize atmospheric CO 2 concentrations. Meaningful capture and storage requires the permanent isolation of enormous amounts of CO 2 away from the atmosphere. We investigate the effectiveness of heterogeneity-induced trapping mechanism, in potential synergy with a self-sealing gravitational trapping mechanism, for secure CO 2 storage in marine sediments. We conduct the first comprehensive study on heterogeneous marine sediments with various thicknesses at various ocean depths. Prior studies of gravitational trapping have assumed homogeneous (deep-sea) sediments, but numerous studies suggest reservoir heterogeneity may enhance CO 2 trapping. Heterogeneity can deter the upward migration of CO 2 and prevent leakage through the seafloor into the seawater. Using geostatistically-based Monte Carlo simulations of CO 2 transport in heterogeneous sediment, we show that strong spatial variability in permeability is a dominant physical mechanism for secure CO 2 storage in marine sediments below 1.2 km water depth (less than half of the depth needed for the gravitational trapping). We identify thresholds for sediment thickness, mean permeability and porosity, and their relationships to meaningful injection rates. Our results for the U.S. Gulf of Mexico suggest that heterogeneity-assisted trapping has a greater areal extent with more than three times the CO 2 storage capacity for secure offshore CO 2 storage than with gravitational trapping. These characteristics offer CO 2 storage opportunities that are closer to coasts, more accessible, and likely to be less costly. [ABSTRACT FROM AUTHOR]

This paper provides pathways of the carbon content of electricity extracted from the Intergovernmental Panel on Climate Change’s fifth Assessment Report scenarios database. It demonstrates three policy-relevant aspects of the carbon content of electricity that are implicit in most integrated assessment model results but under-discussed in academia and the policy debate. First, climate stabilization at any level from 1.5 °C to 3 °C requires the carbon content of electricity to decrease quickly and become almost carbon-free before the end of the century. As such, the question for policy makers is not whether to decarbonize electricity but when and how to do so. Second, decarbonization of electricity is still possible and required if some of the key zero-carbon technologies—such as nuclear power or carbon capture and storage—turn out to be unavailable. Third, progressive decarbonization of electricity is part of every country’s cost-effective means of contributing to climate stabilization. The pathways of the carbon content of electricity reported here can be used to benchmark existing decarbonization targets, such as those set by the European Energy Roadmap or inform new policies in other countries. They can also be used to assess the desirable uptake rates of electric and plug-in hybrid vehicles, electric stoves and heat pumps, industrial electric furnaces, or other electrification technologies. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Implementation of forest-derived climate change mitigation is hampered by complexity within socio-ecological systems. • We capture this complexity by four components to decision-making: cognitive, institutional, strategic, and normative. • A conceptual figure is developed to visualize the main obstacles and to facilitate decision-making pathways. • Further research on these complex issues is needed focusing on the interactions between obstacles in each component. Abstract Managed forests can play an important role in climate change mitigation due to their capacity to sequester carbon. However, it has proven difficult to harness their full potential for climate change mitigation. Managed forests are often referred to as socio-ecological systems as the human dimension is an integral part of the system. When attempting to change systems that are influenced by factors such as collective knowledge, social organization, understanding of the situation and values represented in society, initial intentions often shift due to the complexity of political, social and scientific interactions. Currently, the scientific literature is dispersed over the different factors related to the socio-ecological system. To examine the level of dispersion and to obtain a holistic view, we review climate change mitigation in the context of Swedish forest research. We introduce a heuristic framework to understand decision-making connected to climate change mitigation. We apply our framework to two themes which span different dimensions in the socio-ecological system: carbon accounting and bioenergy. A key finding in the literature was the perception that current uncertainties regarding the reliability of different methods of carbon accounting inhibits international agreement on the use of forests for climate change mitigation. This feeds into a strategic obstacle affecting the willingness of individual countries to implement forest-related carbon emission reduction policies. Decisions on the utilization of forests for bioenergy are impeded by a lack of knowledge regarding the resultant biophysical and social consequences. This interacts negatively with the development of institutional incentives regarding the production of bioenergy using forest products. Normative disagreement about acceptable forest use further affects these scientific discussions and therefore is an over-arching influence on decision-making. With our framework, we capture this complexity and make obstacles to decision-making more transparent to enable their more effective resolution. We have identified the main research areas concerned with the use of managed forest in climate change mitigation and the obstacles that are connected to decision making. [ABSTRACT FROM AUTHOR]

Combatting climate change has risen to the top of the international policy discourse. Effective governance necessitates the generation of concise information on the costs-effectiveness of policy instruments aimed at reducing atmospheric greenhouse gas (GHG) emissions. The marginal abatement cost curve (MACC) approach is a framework commonly used to summarise information of potential mitigation effort, and can help in identifying the most cost-effective managerial and technological GHG mitigation options. Agriculture offers key opportunities to mitigate GHG emissions and utilise carbon (C) sink potentials. Therefore, a number of countries have developed national agricultural MACCs in the last decade. Whilst these MACCs have undoubtedly been catalysers for the information exchange between science and policy, they have also accentuated a range of constraints and limitations. In response, each of the scientific teams developed solutions in an attempt to address one or more of these limitations. These solutions represent ‘lessons learned’ which are invaluable for the development of future MACCs. To consolidate and harness this knowledge that has heretofore been dispersed across countries, this paper reviews the engineering agricultural MACCs developed in European countries. We collate the state-of-the-art, review the lessons learnt, and provide a more coherent framework for countries or research groups embarking on a trajectory to develop an agricultural MACC that assesses mitigations both within the farm gate and to the wider bioeconomy. We highlight the contemporary methodological developments, specifically on 1) the emergence of stratified MACCs; 2) accounting for soil carbon sequestration 3) accounting for upstream and downstream emissions; 4) the development of comprehensive cost-calculations; 5) accounting for environmental co-effects and 6) uncertainty analyses. We subsequently discuss how the mitigation potential summarised by MACCs can be incentivised in practice and how this mitigation can be captured in national inventories. We conclude that the main purpose of engineering MACCs is not necessarily the accurate prediction of the total abatement potential and associated costs, but rather the provision of a coherent forum for the complex discussions surrounding agricultural GHG mitigation, and to visualise opportunities and low-hanging fruit in a single graphic and manuscript. [ABSTRACT FROM AUTHOR]

In this study, the price of carbon is used to incentivize a reduction in the release of CO 2 emissions and an increase in sequestration of CO 2 through forestry activities. Forest managers essentially have two options for increasing carbon sequestration (i.e., creating carbon offset credits): (1) avoid or delay harvest of mature timber; or (2) harvest timber and allow natural or artificial regeneration (with ‘regular’ or ‘seed-selected’ growing stock). A forest management model representative of the southern interior of British Columbia is described and used to examine forest conservation that prevents emissions of CO 2 , and even-flow and commercial harvesting where timber is processed into long-lived wood products that store carbon and residuals for energy. The objective of the model is to maximize net discounted returns to commercial timber operations plus the benefits of managing carbon fluxes. The model tracks carbon in living trees, organic matter, and post-harvest carbon pools. It also includes various parameters related to the weighting of future carbon flows, anticipated price of carbon, whether and to what extent use of biomass reduces fossil fuel emissions from generating electricity or production of non-wood construction materials, et cetera. The results demonstrate that the decision about which forestry activities generate carbon offset credits and how many is essentially a political and not a scientific one. [ABSTRACT FROM AUTHOR]

Wood and other bio-based building materials are often perceived as a good choice from a climate mitigation perspective. This article compares the life cycle assessment of the same multi-residential building from the perspective of 16 countries participating in the international project Annex 72 of the International Energy Agency to determine the effects of different datasets and methods of accounting for biogenic carbon in wood construction. Three assessment methods are herein considered: two recognized in the standards (the so-called 0/0 method and −1/+1 method) and a variation of the latter (−1/+1* method) used in Australia, Canada, France, and New Zealand. The 0/0 method considers neither fixation in the production stage nor releases of biogenic carbon at the end of a wood product's life. In contrast, the −1/+1 method accounts for the fixation of biogenic carbon in the production stage and its release in the end-of-life stage, irrespective of the disposal scenario (recycling, incineration or landfill). The −1/+1 method assumes that landfills offer only a temporary sequestration of carbon. In the −1/+1* variation, landfills and recycling are considered a partly permanent sequestration of biogenic carbon and thus fewer emissions are accounted for in the end-of-life stage. We examine the variability of the calculated life cycle-based greenhouse gas emissions calculated for a case study building by each participating country, within the same assessment method and across the methods. The results vary substantially. The main reasons for deviations are whether or not landfills and recycling are considered a partly permanent sequestration of biogenic carbon and a mismatch in the biogenic carbon balance. Our findings support the need for further research and to develop practical guidelines to harmonize life cycle assessment methods of buildings with bio-based materials. [Display omitted] • Life cycle assessments of the same multi-residential building were carried out by experts from 16 countries. • Effects of methods and datasets of biogenic carbon accounting in wood construction were identified. • Different end-of-life scenarios (incineration, landfill, recycling) cause variations in the results. • Different interpretations of the permanence of storing biogenic carbon in landfills also cause variations in the results. • The input and output flows of biogenic carbon must be balanced to correctly assess its climate change impacts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Topsoil SOC stocks and soil structure recovered 26 years after topsoil removal. • Topsoil buried under the plough layer non-linearly lost 30–50% of SOC in 55 years. • Topsoil SOC recovery and stability of buried SOC was dependent on N fertilisation. Erosion of fertile topsoil means severe land degradation and yield loss. Here, we show that reformation of the fertile topsoil and crop yield increase is possible by good agricultural management within a few decades. Evidence relies on a unique long-term field experiment in NE Germany, where in 1964 the sandy soil (Luvisol) had been excavated to 52 cm and refilled with subsoil material of 52 cm thickness. Undisturbed trials served as controls, these were all combined with either no fertilisation, mineral fertilisation or a combined mineral and organic fertilisation. It took only 26 years until new topsoil had been formed. Its soil organic carbon (SOC) and total N stocks and the aggregate size distributions equalled that of the other treatments; SOC sequestration corresponded to 28 Mg SOC ha−1. The former topsoil buried below the plough layer lost 30–50 percent of its SOC during 5 decades in a non-linear manner. We conclude that our current agricultural tools can restore degraded arable land rather fast and contribute to climate change mitigation through a significant SOC sequestration as well. [ABSTRACT FROM AUTHOR]

• MAOM-C content was modeled for arable fields with different management. • Organic fertilization, crop rotation, and soil texture define MAOM-C content. • A POM-C/MAOM-C ratio indicator was developed and tested. • This indicator contains information on MAOM-C saturation deficits. • POM-C/MAOM-C ratio indicators might support climate mitigation strategies. Soil organic matter (SOM) is indispensable for soil health and, in the context of climate change, is considered a significant CO 2 sink. Improving agricultural management to increase long-term soil organic carbon (SOC) stocks for mitigating climate change requires tools that estimate short and long-cycling SOM pools. In this study, we analyzed changes in fast-cycling particulate organic matter (POM) and slow-cycling mineral-associated organic matter (MAOM) induced by common management practices, i.e., fertilization and crop rotation in topsoils from 25 Central European long-term field experiments. When relating MAOM-C contents to recent MAOM-C saturation levels, estimated sequestration potentials were only met in coarse-textured soils under appropriate agricultural management or fine-textured soils under extreme organic fertilization. Soil texture, organic fertilization, and below-ground OC inputs through root exudates and root biomass were decisive for estimating MAOM-C, allowing for calibration of a mixed-effects model (Nakagawa's: marginal R2 m = 0.6, conditional R2 c = 0.89). While the models containing soil texture and organic fertilization parameters can be validated and generalized (R2 = 0.43), the below-ground OC input predictor substantially decreases the generalizability of the validated models (R2 = 0.14). According to quantile regression models, we estimate the average difference in MAOM-C concentration between well-managed and control site (without organic fertilization) topsoils to 4.1 mg g−1 soil. In dependence on the soil bulk density, this amounts to 1.38 – 1.84 t ha−1 MAOM-C stocks or 5.06 – 10.1 t ha−1 CO 2 -equivalents. POM-C was difficult to predict (R2 = 0.28), presumably due to strong POM dynamics. The POM-C / MAOM-C ratio can inform on the effects of agricultural practices in before/after management change comparisons. Under increasing SOC concentration, an increasing POM-C / MAOM-C ratio indicates that the effects of organic fertilization do not transfer to real effects on long-term SOC sequestration. Because MAOM-C depends on soil texture, this ratio is also a covariate of soil texture, limiting it for comparisons between sites with different textures. However, our data indicate that agricultural long-term field experiment soils constantly approximate MAOM-C saturation when the POM-C/MAOM-C ratio is >0.35. This ratio might be used as a management goal to prevent organic over-fertilization and N loss, especially on coarse-textured soils. Thereby, the POM-C / MAOM-C ratio can help to optimize SOC management and sequestration on agricultural soils and support climate change mitigation strategies in Central Europe. [ABSTRACT FROM AUTHOR]

• We evaluated on-farm management and site predictors for soil organic carbon storage. • Soil texture strongly predicted soil organic carbon sequestration potentials. • Conservation management practices were overall of less importance. • Future carbon farming schemes need to properly account for biophysical constraints. Although conservation agriculture practices evidently facilitate the build-up of soil organic carbon (SOC), the sequestration potential of arable soils is strongly mediated by edaphic attributes; so far, their interplay is not well understood. Deciphering these drivers is however important to correctly estimate SOC storage potentials in arable soils and to derive effective strategies for the implementation of successful measures. By using an on-farm approach, we conducted a pairwise comparison of 21 conventional and highly innovative 'pioneer' farms across a wide range of arable soil types and evaluated the leverage of site attributes and management practices such as crop diversity, reduced tillage, organic fertilization, cover cropping and inter cropping on the SOC sequestration potential. While most pioneer management practices proved beneficial for the sequestration of SOC – particularly cover cropping and crop diversity – our results clearly show that soil texture was the most significant shaping factor. Coarse-textured soils had a significantly higher potential for SOC accrual compared to medium- and fine-textured soils. The initial SOC content also had a significant effect on prevalent sequestration potentials. Based on the fact of a clear predominance of natural site conditions over management impacts in enhancing SOC storage of arable soils, we call for a critical discussion of carbon farming schemes. As similar efforts and costs of implementing carbon farming measures will have distinctive carbon gains, dependent on environmental constraints beyond farmers' influence, we advocate for strategies harmonizing both activity- and results-based approaches to maximize the ecological effectiveness and the spatial dissemination of soil health innovations. Carbon farming schemes thus need reconsideration within the state-of-the-art scientific framework of carbon saturation behaviour in order to properly account for biophysical constraints when formulating soil-related climate change mitigation policies. [ABSTRACT FROM AUTHOR]

• Soil organic carbon (SOC) stabilities were studied in two agroforestry systems. • We studied hedgerow and shelterbelt systems and their component land-uses (cropland vs forest). • The biological stability of SOC was higher in hedgerow than in shelterbelt system. • The biological stability of SOC was higher in cropland than in forest land-use. • Agroforestry system by land-use interactively affected the thermal stability of SOC. Agroforestry systems play important roles in carbon (C) sequestration in western Canada. However, the effect of agroforestry system type and their component land-uses (forested area and cropland) on soil organic C (SOC) stability is poorly understood. We studied SOC stability in surface soils from two agroforestry systems (shelterbelt system and hedgerow system) and their component land-uses (forested area and cropland) in western Canada. A 61-day laboratory incubation was used to assess SOC biological stability, and compared to thermal stability measured during ramped combustion. The shelterbelt system had a lower biological stability than the hedgerow system as indicated by the higher cumulative soil respiration and SOC loss during incubation. Cumulative respiration and SOC loss during incubation in the forested area was 1.63 and 1.57 times that in the cropland, indicating a lower SOC biological stability in the former. Thermal stability indicators, CO 2 -T 50 (the temperature at which half of the CO 2 is produced), DSC-T 50 (the temperature at which half of the exothermic energy of the SOC is released) and ROI (return on energy investment) were influenced by the interactive effects of the agroforestry system by land-use, while TG-T 50 (the temperature at which half of the exothermic mass is lost) and Ed (energy density) were influenced by land-use and the interactive effects of agroforestry system by land-use. Hedgerow cropland had a higher SOC thermal stability (higher TG-T 50) than the hedgerow forested area, while there was no difference among shelterbelt cropland, and the forested areas of shelterbelt and hedgerow system. We conclude that planting trees on agricultural land to form agroforestry systems alters SOC biological and thermal stabilities, and the hedgerow system may have a more stable SOC than the shelterbelt system, thus, maintaining the hedgerow system may enhance C stability, promote C sequestration and climate change mitigation. [ABSTRACT FROM AUTHOR]

• The drought-induced AGB decline occurred only at aridity levels > 0.37. • Higher SOM content led to increased AGB, with greater gains below 2.5% SOM. • SOM alleviates the adverse effects of drought on AGB by improving soil structure. Increasing the resilience of plant productivity to drought is crucial for provisioning ecosystem services. Although soil organic matter (SOM) promotes plant growth, whether SOM mitigates aboveground biomass (AGB) loss due to drought in alpine grasslands remains unclear. Here, we evaluated the link between AGB and SOM across 209 alpine grassland sites along a 3,500-km aridity gradient on the Tibetan Plateau. We observed that AGB decreased in response to increasing aridity severity only when the aridity level was above a threshold of 0.37. We further found a stronger positive relationship between AGB and SOM in more arid conditions than in less arid ones, with an abrupt increase beyond an aridity threshold of 0.64. Our results confirm that SOM alleviates drought stress on AGB, mainly by reducing bulk density, increasing fine fraction aggregates, and increasing cation exchange capacity. The identified aridity thresholds and mechanisms emphasise the importance of soil carbon sequestration strategies for biomass production and climate change mitigation in arid areas. [ABSTRACT FROM AUTHOR]

Although post-combustion carbon capture (PCC) has been regarded as a near-commercial technology, the scale-up development of PCC the technology remains hindered by its severe thermodynamic and economic penalties. As a consequence, the solar-assisted carbon capture and storage (CCS) technology is emerging recently, which poses a promising possibility to offset the power generation loss caused by the intensive energy consumption from PCC process. Nevertheless, the application potential of the solar-assisted CCS technology would highly depend on its realistic greenhouse gas (GHG) mitigation benefit as well as its cost relative to alternative low carbon technologies. Thus, it is required to apply an improved assessment practice to recognize solutions for such sustainable power supply chains, considering an increasing threatening from climate change. In this study, solar-assisted post-combustion CCS processes are analyzed trough a life cycle approach, combing life cycle GHG assessment and life cycle cost analysis. A typical 300MWe coal-fired power plant in China is taken as the case study. Three scenarios are further analyzed: (1) base case integrated with CCS process; (2) base case integrated with CCS and solar-assisted reboiler heating process; (3) base case extended to CCS and solar-assisted repowering process. Results show that the solar-assisted repowering case has considerable advantage in both GHG mitigation potential and cost aspect with superior life cycle GHG reduction rate and life cycle cost of energy removed (LCOR) at 73.7% and 37.2$/ t c o 2 − e q respectively. While the solar-assisted reboiler heating case does not have evident competition superiority. It is further highlighted that the GHG emissions from the upstream and transportation stages are also critical for Chinese CCS chains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phase equilibria of CO 2 + DIOX hydrate for C DIOX between 0.05 mol% and 5.56 mol% • The kinetics of CO 2 + DIOX hydrate is quantified with morphology observation. • Phase separation of DIOX/H 2 O above 3.1 MPa weakens the promotion effect of DIOX. • A comprehensive evaluation of DIOX in the application of hydrate-based CO 2 storage. To reduce anthropogenic CO 2 emissions for the mitigation of climate change require novel CCUS solutions. Hydrate-based CO 2 sequestration (HCS) is a novel carbon-neutrality technology that aims to store CO 2 in solid hydrate form with long-term stability. However, imminent issues exist for the application of HCS in terms of demanding thermodynamic conditions, slow formation kinetics, and low CO 2 gas uptake. These challenges necessitate the quest for an efficient and eco-friendly CO 2 hydrate promoter. In this study, 1,3-dioxolane (DIOX) as a low-toxicity CO 2 hydrate promoter was systematically examined. The phase equilibria, cage occupancy, and the kinetics of binary CO 2 + DIOX hydrate were measured for DIOX concentrations (C DIOX) varying from 0.05 mol% to 5.56 mol%. It was confirmed that DIOX is a dual-function promoter for CO 2 hydrate, but its promotion effect is weakened for C DIOX between 0.60 mol% and 1.00 mol% and for all C DIOX at relatively high pressure. The CO 2 uptake in the hydrate phase increases with C DIOX above 2.00 mol% and is the highest for C DIOX = 5.56 mol% (57.08 ± 6.39 mmol/mol). Based on the morphology observation, hydrate transits from ice-like to slurry to mushy-like and finally to snow-like with increasing C DIOX. Interestingly, we observed that the aqueous phase separates into two phases (i.e., DIOX-rich and H 2 O-rich) at pressure above 3.09 MPa, which explains the gradual loss of the promotion effect. The results of our study provide a comprehensive evaluation on DIOX as a possible promoter for CO 2 hydrate in HCS application. [ABSTRACT FROM AUTHOR]