Natural Carbon Sinks Research Articles

Analysis of emission reduction strategies for the use of alternative fuels and natural carbon sinks in international bulk shipping

This research examines four categories of international bulk carriers and forecasts their ability, from 2025 to 2050, to meet the IMO targets for emission reduction: a 20% reduction by 2030 and a 70% reduction by 2040 compared to 2008 levels, with the ultimate aim of achieving net-zero emissions by 2050, utilizing a life cycle assessment (LCA) methodology. It evaluates various scenarios involving different rates of ship demolition and alternative fuel adoption to achieve these targets. Additionally, it investigates the potential costs associated with carbon credits and natural carbon sinks (such as seagrass) in cases where emissions targets are not met. The findings suggest that, under the baseline scenario and Scenario 1, despite increased usage of alternative fuels and declining emission factors, none of the four ship types meet the IMO targets in terms of life cycle greenhouse gas (GHG) emissions. However, in Scenario 2, where the ship demolition rate steadily increases until the usage of traditional fuel ships reaches zero, and with concurrent reductions in emission factors, emissions decrease substantially and approach the desired targets, though they still fall short. Furthermore, the study analyzes the financial implications of employing carbon credits versus natural carbon sinks to offset emission shortfalls, indicating that Scenario 2 is comparatively less costly. It also demonstrates that leveraging natural carbon sinks is more cost-effective in reducing emission expenses compared to relying solely on carbon credits. Consequently, the research recommends prompt adoption of alternative fuels, acceleration of ship demolition rates, and utilization of natural carbon sinks not only to meet international shipping emission reduction objectives but also to rejuvenate marine ecosystems, thereby fortifying marine environments.

The importance of natural land carbon sinks in modelling future emissions pathways and assessing individual country progress towards net-zero emissions targets

Nature-based solutions (NBS), in the form of active ecosystem conservation, restoration and improved land management, represent a pathway to accelerate net-zero emissions (NZE) strategies and support biodiversity. Meaningful implementation and successful accounting depend on the ability to differentiate between anthropogenic and natural carbon fluxes on land. The United Nations Framework Convention on Climate Change (UNFCCC) land carbon accounting methods currently incorporate all CO2 fluxes on managed land in country inventories without distinguishing between anthropogenic and natural components. Meanwhile, natural land carbon sinks are modelled by earth system models but are mostly reported at global level. Here we present a simple yet novel methodology to estimate the present and future progression of natural land sinks at the country and regional level. Forests dominate the uptake of CO2 on land and as such, our analysis is based on allocating global projections of the natural land carbon flux to individual countries using a compilation of forest land areas for a historic and scenario range spanning 1960–2100. Specifically, we use MIT’s carbon cycle model simulations that are set in the context of emissions pathways from the Shell Energy Security Scenarios (2023). Our natural land carbon flux estimates for individual countries and regions such as the European Union (EU) show generally good agreement with independent estimates from recent land-use harmonisation studies for 2000–2020. Hence, our approach may also provide a simple, first-order exploration of future natural land fluxes at country level—a potential that other studies do not yet offer. In turn, this enables better understanding of the anthropogenic and natural components contributing to country NZE targets under different scenarios. Nevertheless, our findings also suggest that models such as the Shell World Energy Model (WEM) would benefit from further improvements in the apportionment of land carbon sources and sinks to evaluate detailed actions to meet country targets. More importantly, uncertainties remain regarding the resilience of land ecosystems and their capacity to store increasing amounts of carbon under progressive global warming. Therefore, we recommend that the carbon cycle modelling and energy modelling research communities continue to collaborate to develop a next generation of relevant data products to distinguish anthropogenic from natural impacts at local, regional and national levels.

Towards carbon neutral cities: An insight for Istanbul, Turkey

AbstractTurkey pledged net‐zero emissions by 2053 under the Paris Agreement. Istanbul, its largest city, aims to be carbon‐neutral by 2050. To accomplish this goal, the first step involves identifying emissions and devising reduction plans, with a focus on utilizing natural carbon sinks. This study assessed emissions and potential reductions across Istanbul's 39 districts. Greenhouse gas emissions were calculated using Intergovernmental Panel on Climate Change guidelines. Despite limited data on sink efficacy, a practical approach was adopted. According to the results, Istanbul emitted 58.5 million tons of CO2 equivalent, varying by district in 2022. In Istanbul, 32% of emissions come from electricity consumption, 29% from heating, 29% from transportation, and 10% from waste disposal. High emissions were observed near waste sites or airports. Carbon sinks reduced emissions by 11.5%, with only two districts achieving neutrality. Natural processes alone are not enough; urgent reduction strategies are needed, prioritizing high‐emission districts over citywide measures.

Study of Carbon Sequestration in Forest Ecosystems in DRC

Purpose: The aim of the study was to investigate the study of carbon sequestration in forest ecosystems in DRC. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: Research on carbon sequestration in DRC's forests underscores their crucial role as significant carbon sinks. These forests store substantial amounts of carbon in biomass and soils, contributing significantly to global climate regulation efforts. However, challenges like deforestation and illegal logging threaten this capacity, highlighting the importance of sustainable forest management and conservation. Enhancing carbon sequestration in DRC's forests is essential for mitigating climate change impacts and preserving biodiversity. Unique Contribution to Theory, Practice and Policy: Ecological succession theory, resource allocation theory & social-ecological systems theory may be used to anchor future studies on the study of carbon sequestration in forest ecosystems in DRC. Encourage the adoption of sustainable forestry practices that enhance carbon sequestration while supporting biodiversity conservation and local livelihoods. Align forest management policies with national and international climate change mitigation goals, emphasizing the role of forests as natural carbon sinks.

On the irrelevance of (peat-free) substrates - Qualitative insights into the social practices of hobby gardeners in Germany

Reducing peat consumption in hobby gardening offers considerable potential for reducing CO2 emissions, since peatlands are one of the most important natural carbon sinks. While existing research focuses on the products and their diffusion, we focus on people and their practices of gardening. So we conducted 44 interviews with hobby gardeners in Germany from three different contexts: gardening at home, in an allotment garden, and in an urban gardening initiative. Our findings show that substrates are not a major part of gardeners' social interactions. Purchasing substrates is a utility-driven process with, compared to gardening itself, mostly passive information behavior. Although (basic) knowledge about peat is widespread among hobby gardeners, price is the dominant purchase criterion for substrates; sustainability does not play an important role. Our results suggest that communication campaigns by governments and companies should convey substrate-related messages in those places where gardeners go to seek information, e.g. gardening-related publications. Communication should focus on the functional value of peat-free substrates and not just explain environmental benefits. Lastly, campaigns should target home gardeners rather than urban gardeners and allotment gardeners who rarely buy any substrates but rely on their own production.

Terrestrial inputs boost organic carbon accumulation in Mexican mangroves

Despite their ability to mitigate climate change by efficiently absorbing atmospheric carbon dioxide (CO2) and acting as natural long-term carbon sinks, mangrove ecosystems have faced several anthropogenic threats over the past century, resulting in a decline in the global mangrove cover. By using standardized methods and the most recent Bayesian tracer mixing models MixSIAR, this study aimed to quantify source contributions, burial rates, and stocks of organic carbon (Corg) and explore their temporal changes (∼100 years) in seven lead-210 dated sediment cores collected from three contrasting Mexican mangrove areas. The spatial variation in Corg burial rates and stocks in these blue carbon ecosystems primarily depended on the influence of local rivers, which controlled Corg sources and fluxes within the mangrove areas. The Corg burial rates in the cores ranged from 66 ± 16 to 400 ± 40 g m−2 yr−1. The Corg stocks ranged from 84.9 ± 0.7 to 255 ± 2 Mg ha−1 at 50 cm depth and from 137 ± 2 to 241 ± 4 Mg ha−1 at 1 m depth. The highest Corg burial rates and stocks were observed in cores from the carbonate platform of Yucatan and in cores with reduced river influence and high mangrove detritus inputs, in contrast to patterns identified from global databases. Over the past century, the rising trends in Corg burial rates and stocks in the study sites were primarily driven by enhanced inputs of fluvial-derived Corg and, in some cores, mangrove-derived Corg. Despite their decreasing extension, mangrove areas remained highly effective producers and sinks of Corg. Ongoing efforts to enhance the global database should continue, including mangrove area characteristics and reliable timescales to facilitate cross-comparison among studies.

Seagrass decline weakens sediment organic carbon stability

Seagrass meadows are globally recognized as critical natural carbon sinks, commonly known as ‘blue carbon’. However, seagrass decline attributed to escalating human activities and climate change, significantly influences their carbon sequestration capacity. A key aspect in comprehending the impact of seagrass decline on carbon sequestration is understanding how degradation affects the stored blue carbon, primarily consisting of sediment organic carbon (SOC). While it is widely acknowledged that seagrass decline affects the input of organic carbon, little is known about its impact on SOC pool stability. To address this knowledge, we examined variations in total SOC and recalcitrant SOC (RSOC) at a depth of 15 cm in nine seagrass meadows located on the coast of Southern China. Our findings revealed that the ratio of RSOC to SOC (RSOC/SOC) ranged from 27 % to 91 % in the seagrass meadows, and the RSOC/SOC increased slightly with depth. Comparing different seagrass species, we observed that SOC and RSOC stocks were 1.94 and 3.19-fold higher under Halophila beccarii and Halophila ovalis meadows compared to Thalassia hemprichii and Enhalus acoroides meadows. Redundancy and correlation analyses indicated that SOC and RSOC content and stock, as well as the RSOC/SOC ratio, decreased with declining seagrass shoot density, biomass, and coverage. This implies that the loss of seagrass, caused by human activities and climate change, results in a reduction in carbon sequestration stability. Further, the RSOC decreased by 15 %, 29 %, and 40 % under unvegetated areas compared to adjacent Halophila spp., T. hemprichii and E. acoroides meadows, respectively. Given the anticipated acceleration of seagrass decline due to climate change and increasing coastal development, our study provides timely information for developing coastal carbon protection strategies. These strategies should focus on preserving seagrass and restoring damaged seagrass meadows, to maximize their carbon sequestration capacity.

О поглощении антропогенного диоксида углерода лесами и степной растительностью Республики Тыва

INTRODUCTION. Currently, a coal mining territory is being formed in the Republic of Tyva, the volume of coal mining, the “carbon intensity” of production, and СО2 emissions into the atmosphere are increasing. Emissions of the man-made СО2 into the atmosphere caused by combustion of hydrocarbon fuels, wildfires, deforestation and land use development change the natural СО2 balance in the atmosphere, which is manifested in the photosynthesis and respiration processes of plants with the formation of natural carbon sinks. OBJECTIVES. The research aims to correlate the calculated data on the degree of atmospheric pollution by carbon dioxide emissions from stationary and mobile sources with the sequestration potential (with respect to СО2) of the forest and steppe ecosystems of the Republic of Tyva. RESULTS. The sequestration potential of the ecosystems of the Republic of Tyva makes it possible to capture both its own carbon dioxide emissions (fuel combustion) and those introduced from other regions. CONCLUSIONS. The total impact of the man-made СО2 on the atmosphere in the city of Kyzyl relative to other regions is low, amounting to 1,41 million t-eq СО2/year; currently, the territory of the Republic of Tyva is characterized by an excess of the sequestration capacity of man-made СО2 (7,46 million t-eq СО2/year).

Structure and composition of rehabilitated mangrove in Lubuk Kertang Village, North Sumatra, Indonesia

Mangroves are generally distributed in tidal zones along tropical and subtropical coasts and are known as woody halophytes. Mangroves are one of the most productive and efficient long-term natural carbon sinks. Deforestation and mangrove degradation produced substantial carbon emissions that account for the majority and salt marshes emissions. Mangroves play an important role in protecting against storms and sea level rise, preventing coastline erosion, regulating coastal water quality, providing habitat for commercial interests. This study was conducted to measure the diversity, structure and composition of forests in the rehabilitation of abandoned pond mangrove forests in Lubuk Kertang Village, West Brandan District, Langkat Regency, North Sumatra. The method used was to conduct a census in a 1.6 ha restoration forest by measuring the overall diameter, height and species found. Fourteen species were found, namely Aegiceras corniculatum, Avicennia marina, Acrostichum aureum, Bruguiera gymnorrhiza, Ceriops tags, Exoecaria agallocha, Finlaysonia maritimea, Nypa fruticans Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia alba, Scyphiphora hydrophyllacea, Sesuvium portulacastrum.

Enhancing wood efficiency through comprehensive wood flow analysis: Methodology and strategic insights

Wood, an essential natural resource in human civilization, remains widely used despite advances in technology and material substitution. The surge in greenhouse gas emissions and environmental concerns accentuates the need for optimizing wood utilization. Material flow analysis is a powerful tool for tracking material flows and stocks, aiding resource management and environmental decision-making. However, the full extent of its methodological dimensions, particularly within the context of the wood supply chain, remains relatively unexplored. In this study, we delve into the existing literature on wood flow analysis, discussing its primary objectives, materials involved, temporal and spatial scales, data sources, units, and conversion factors. Additionally, data uncertainty, data reconciliation and crucial assumptions in material flow analysis are highlighted in this paper. Key findings reveal the significance of wood cascading and substitution effects by replacing non-wood materials, where they can reduce greenhouse gas emissions more than the natural carbon sink of forests and wood products. The immediate impact of short-term wood cascading might not be as robust as the substitution effect, with energy substitution showcasing better results than material substitution. However, it's crucial to note that these conclusions could experience significant reversal from a long-term and global perspective. Strategies for improving wood efficiency involve maximizing material use, advancing construction technologies, extending product lifespans, promoting cascade use, and optimizing energy recovery processes. The study underscores the need for standardized approaches in wood flow analysis and emphasizes the potential of wood efficiency strategies in addressing environmental challenges.

Focused recharge enhances soil carbon leakage and carbonate weathering in groundwater: Implications for subsurface carbon sinks

Soil carbon leakage into groundwater is a crucial and natural carbon sink process in the subsurface carbon cycling. However, the primary driving force for soil carbon downward leakage and the following fate of the carbon in groundwater remains elusive. Here, we investigated multi-seasonal hydrodynamics, hydrogeochemistry and environmental isotopes (δ13C, δ2H and δ18O) in groundwater wells in a humid region. Frequent water-table rise (1 ∼ 3 m) and isotopic signature fluctuation after the concentrated rainfall supported evidence for the occurrence of focused groundwater recharge. We found that focused recharge during the shorter and wetter season induced the increase of groundwater DOC (306.5 ± 231 μmol/L) and CO2 (2154 ± 726.6 μmol/L), the dilution of CH4 (1.75 ± 1.2 μmol/L) and DIC (4486 ± 790.8 μmol/L) as well as depleted δ13C signatures (−17‰ ∼ −18‰). These variations jointly elucidated accelerated soil carbon downward leakage and hydrodynamic mixing driven by focused recharge. Saturation index calculation and PHREEQC simulations confirmed that massive groundwater CO2 from soil carbon leakage during focused recharge exerted positive perturbations on carbonate weathering, and ultimately stored in a more stable form by transforming into HCO3−. Carbon isotope analysis further identified carbonate weathering accounted for approximately one third of DIC dynamics compared to biogenic sources. This study highlights that focused recharge has a disproportional contribution to flushing soil-derived carbon into groundwater and activating carbonate weathering in the groundwater, with important implications for temporal variability of non-negligible subsurface carbon sinks in the global carbon budget.

Carbon Sequestration Through Forestry: A Differential Equation Approach

Carbon sequestration through forestry represents a promising approach to partially counteract anthropogenic greenhouse gas emissions driving climate change. Tree growth naturally removes carbon dioxide from the atmosphere, storing it as biomass. Sustainably managed forests can effectively function as carbon sinks. However, determining optimal forestry policies involves balancing complex ecological dynamics with economic constraints. This study develops differential equation models quantitatively capturing forest growth, timber harvesting, and carbon sequestration dynamics. Logistic models are first adapted to simulate biomass accumulation of representative tree species. Lifecycle growth patterns spanning juvenile to mature phases are incorporated, along with climate effects. Biomass levels are proportionally related to carbon dioxide removal rates from the atmosphere. Deforestation impacts are analyzed by incorporating harvesting-induced biomass reductions. Sustainability constraints are implemented to ensure minimum viable tree densities across harvest rotations. Optimization techniques then identify management guidelines maximizing economic returns given ecological stability considerations. The goal is providing quantitative insights into rotation lengths, planting densities, and allowable cuts upholding both climate change mitigation and commercial demands. Findings can inform science-based forestry policies to leverage forests as sustainable natural carbon sinks.

Carbon stock potential in rehabilitated mangrove in Lubuk Kertang Village, North Sumatra, Indonesia

Mangrove forests are one of the most productive and efficient long-term natural carbon sinks, tropical natural resources that have social, economic and ecological benefits. Even though the area of mangrove forests is relatively large in of the world, the consequences of various anthropogenic cause various damages. Given their global significance as a large carbon sink, preventing mangrove loss would be an effective climate change adaptation and mitigation strategy. This research was conducted to analyze carbon stocks in mangrove forests resulting from the rehabilitation of former pond land in Lubuk Kertang Village, West Brandan District, Langkat, North Sumatra, Indonesia. The census method was applied in this study, to calculate the value of carbon stocks using an allometric equation with DBH > 5cm. The aboveground biomass was 15.54 Mg/ha. Soil sampling for organic carbon content by collecting a sub-sample 5 cm from the center of the core. The total value of the total carbon stock above and below the soil surface is 9.42 Mg/ha1 and soil carbon is 685 MgC/ha1.

Abandoned cropland compensates the decrease in net ecosystem productivity of impervious surface expansion in China

Abandoned cropland and impervious surface expansion are generally considered to have positive and negative impacts on net ecosystem productivity (NEP), respectively. However, the comprehensive comparison of the impacts of these two land use changes on NEP remains lacking. We use multi-year land cover data, NEP data, and statistical data to track the interannual variability of abandoned cropland and impervious surface expansion in China, and subsequently estimate their impacts on NEP. From 2000 to 2019, 30.8 × 106 ha of cropland in China was abandoned, while the impervious surface area expanded by 8.97 × 106 ha over the period. The average annual abandonment rate and impervious surface expansion rate were 0.83% and 2.96%, respectively. The average annual NEP of abandoned cropland and impervious surface expansion were 39.9 g C/m2 and 16.2 g C/m2, respectively. Using the space-for-time method to estimate NEP changes, results showed that the carbon sink of 0.013 Tg C accumulated by abandoned cropland not only offset the carbon source of 0.01 Tg C from impervious surface expansion but sequestered additional 0.003 Tg C during the study period. Further analysis of the relationships between NEP and natural and anthropogenic factors revealed that temperature had the most significant positive impact on NEP (0.35, p < 0.01), while the urbanization rate had the most significant negative impact on NEP (−0.33, p < 0.01). This study provides a new insight for regulating the effects of land use changes on natural carbon sink/source, and highlights the importance of abandoned cropland to enhancing natural carbon sink.

Committed Global Warming Risks Triggering Multiple Climate Tipping Points

AbstractMany scenarios for limiting global warming to 1.5°C assume planetary‐scale carbon dioxide removal sufficient to exceed anthropogenic emissions, resulting in radiative forcing falling and temperatures stabilizing. However, such removal technology may prove unfeasible for technical, environmental, political, or economic reasons, resulting in continuing greenhouse gas emissions from hard‐to‐mitigate sectors. This may lead to constant concentration scenarios, where net anthropogenic emissions remain non‐zero but small, and are roughly balanced by natural carbon sinks. Such a situation would keep atmospheric radiative forcing roughly constant. Fixed radiative forcing creates an equilibrium “committed” warming, captured in the concept of “equilibrium climate sensitivity.” This scenario is rarely analyzed as a potential extension to transient climate scenarios. Here, we aim to understand the planetary response to such fixed concentration commitments, with an emphasis on assessing the resulting likelihood of exceeding temperature thresholds that trigger climate tipping points. We explore transients followed by respective equilibrium committed warming initiated under low to high emission scenarios. We find that the likelihood of crossing the 1.5°C threshold and the 2.0°C threshold is 83% and 55%, respectively, if today's radiative forcing is maintained until achieving equilibrium global warming. Under the scenario that best matches current national commitments (RCP4.5), we estimate that in the transient stage, two tipping points will be crossed. If radiative forcing is then held fixed after the year 2100, a further six tipping point thresholds are crossed. Achieving a trajectory similar to RCP2.6 requires reaching net‐zero emissions rapidly, which would greatly reduce the likelihood of tipping events.

Urban Flora Structure and Carbon Storage Potential of Woody Trees in Different Land Use Units of Cotonou (West Africa)

Urbanization is a current concern, particularly in Africa, where it is expected to continue and increasingly threaten the effectiveness of plant biodiversity, natural carbon sinks, and the sustainability of cities. This paper investigates the structural parameters and carbon storage potential of trees in the land use units of the city of Cotonou in southern Benin. A total of 149 plots at 2500 m2 each were randomly generated, and trees with a diameter ≥ 10 cm were inventoried. ANOVA revealed that the means of structural parameters (diameter and height classes) and carbon stock rate varied significantly (p &lt; 0.001) across land use units in the city. Tree basal area is estimated at 4.52 ± 5.24 m2 ha−1, with an average of 12.72 (13) feet ha−1. The average diameter of the trees is estimated at 57.94 ± 29.71 cm. Approximately 1000 kg ha−1 (0.94 × 103 kg ha−1) of carbon is stored in the city of Cotonou. Green spaces (1.21 × 103 kg ha−1) and roads (1.19 × 103 kg ha−1) are the units that recorded the highest carbon stocks. Khaya senegalensis, Mangifera indica, and Terminalia mentally lead the top ten species with high stock potential. This study demonstrates the contribution of urban trees to global atmospheric carbon reduction, which varies by species, land use units, and tree density. Future research could investigate an i-Tree Landscape approach for urban carbon estimation. This could reinforce urban carbon data availability for urban ecological planning.

Evidence of gas formation and venting in organic soils: experimental evidence and modelling approach

Peatlands have been recognised to provide a natural carbon sink thanks to waterlogged conditions, which keep summertime temperatures relatively low, increase their water holding capacity, decrease the organic soil decomposition rate by creating anoxic conditions and eventually keeping high water table. However, unfavourable environmental conditions due to increasing temperatures and more frequent droughts will reduce water retention of peats and the summertime insulation, in turn increasing their temperature sensitivity and their decomposition rate [1]. As a result, peatlands may start inverting their positive cycle and emitting greenhouse gases, including CO2 and CH4 [2], which suggests better investigating how increasing climate stresses will affect the efficiency of peats in the greenhouse gases cycle and CO2 sequestration.&#x0D; Some evidence of gas production from increasing decomposition rate in the Netherlands is coming from continuous pore pressure measurements in saturated layers below the water table, which are monitored to assess the safety of the water defence and the transportation infrastructures. Increasing water pressure in closed piezometers compared to vented ones seem to suggest that gas is produced and capped in the ground, until the breakthrough pressure is reached and the gas vents from cracks opened in the soil matrix. Besides the environmental issues, increasing gas production from decomposition is becoming of concern for the stability of embankments made of organic soils, where the effective stress may be lowered to such an extent to endanger their stability. As a matter of fact, in the last ten years, gas overpressure has been claimed to be a triggering or a contributing factor in few small failures experienced by regional dykes in the Netherlands. In spite of the evidence [e.g. 3] and the risk increasing with heat waves and drought events, the role of gas on the coupled hydromechanical response of organic soils has been seldom investigated nor properly understood yet.&#x0D; In the section of Geoengineering at TU Delft, a research effort has been undertaken in the last years to investigate in depth the role of gas formation and venting on the coupled hydro-mechanical response of organic layers in the subsoil of water defence embankments. Preliminary laboratory tests performed on peats to fill this gap showed the role of increasing gas content on their compressibility and on the mobilised shear strength at given strains [4, 5]. The volumetric response of peats including gas was tentatively interpreted with a simple non-linear elastic model, which proved able to model the experimental results [6].&#x0D; A similar model was used to numerically investigate the relevance of gas production and venting on the response of a regional dyke in the Netherlands, where gas bubbles from venting were observed after excavating - unloading - the toe of the dyke during a stress test. Fully coupled three-phases hydromechanical numerical analyses were performed with CODE_Bright [7] to include gas overpressure. A gas content of 6% in volume was artificially generated in the peat layer, capped by a clay layer on top, and let reaching an equilibrium distribution, which depends on the stress-strain response of the different layers and their volumetric compressibility (Figure 1(a)). Gas venting is triggered by simulating excavation at the toe of the dyke, which allows gas escaping after the capping clay is removed.&#x0D; The variation in the operative stress, on which stiffness and strength are assumed to depend [6], is shown in Figure 1(b) over gas generation and venting. In spite of the small amount of gas generated, the predicted overpressure is enough to bring the operative stress to zero in the upper meter of soil at the toe of the embankment due to the light weight of peat and cover soil, which temporarily reduces the factor of safety of the water defence against global stability. As soon as the gas overpressure is released, the operative stress increases above the effective stress which would characterise saturated conditions, bringing the system back to safer conditions.&#x0D; These preliminary analyses are supporting an undergoing experimental and numerical thorough effort to better quantify the dynamics of gas generation and venting in organic soils to reduce the hazard associated with increasing climatic stresses.

Reforestation of Urban Districts in Mediterranean Climate: New Decarbonization Models for Cities

The transformation of cities and urban and peri-urban neighborhoods into flexible, adaptive, and sustainable organisms, in the context of the latest European policy proposals on climate, energy, transportation, land use and resources, have become today's issues that can no longer be postponed. These issues introduce the focus that has been experimentally analyzed through the study, census, and subsequent cataloging of more than 100 tree and shrub species found in the Mediterranean basin according to their carbon uptake and storage capacities, defining a synoptic framework useful, for actors in the field, in silviculture and urban reforestation. These solutions led to the compilation of a detailed database through experimental research that took place in a public housing neighborhood of the Municipality of Rome Capital, the subject of a proposed urban redevelopment, numerically quantifying the carbon absorbed and stored for each individual species. The topic is of great scientific relevance considering national and European strategies and the proposal, put forward by the European Commission, on the New EU Forestry Strategy Fit for 55. Keywords: urban reforestation, urban district, natural carbon sinks

Rawls in the mangrove: Perceptions of justice in nature‐based solutions projects

Abstract Adapting to and mitigating against climate change requires the protection and expansion of natural carbon sinks, especially ecosystems with exceptional carbon density such as mangrove forests (an example of ‘blue carbon’). Projects that do this are called ‘nature‐based solutions’ (NbS). International norms regulating NbS stipulate the importance of justice, in contrast with some of the history and practice in wider conservation. However, what justice means and how it manifests in practice remain contentious. Selling carbon credits on the voluntary market is a growing source of funding for NbS. A large literature examines the ethics, economics, science and politics of such payments for ecosystem services (PES), including for blue carbon. The interpretations of justice in this context are particularly contentious, but operational blue carbon projects have not been examined from a justice perspective. Here we report on a case study involving the first blue carbon project, Mikoko Pamoja, and its sister project Vanga Blue Forest, both based in Kenya. We consider how justice is conceived by local participants and beneficiaries, using interviews, focus groups and participant observation to collect data, as well as by international stakeholders and in relevant governing documents and policy. We compare these perceptions with expectations and critiques derived a priori from the literature, including a classic thought experiment that influential justice philosopher John Rawls called the ‘original position’. In contrast to high‐level policy and much of the literature, but in common with Rawls, local stakeholders emphasised distributional aspects of justice. Locally situated interpretations of contentious issues such as elite capture and commodification differed markedly from common interpretations in the literature. Our work emphasises the importance of situating abstract concepts in their local contexts when evaluating justice in NbS projects. It shows how narratives advocating technical precision and economic efficiency in NbS can militate against transparency and agency at a local level and emphasises the critical importance of benefit sharing that is perceived to be fair. Read the free Plain Language Summary for this article on the Journal blog.

Decoupling Analysis of Carbon Emissions and Forest Area in China from 2004 to 2020

As the largest ecological carbon sequestration systems on the Earth, forests play a significant role in reducing carbon dioxide, and countries around the world are actively expanding their forest areas. However, China’s carbon emissions and forest area have shown an upward trend, which has seriously hindered the implementation of forestry carbon sequestration projects. This paper analyzed the temporal variation, spatial distribution, and deviation degree of the forest area and carbon emissions in China from 2004 to 2020 by using a decoupling model and a coordination model. Firstly, according to the decoupling model, the national carbon emissions and forest area are negatively decoupled. At the provincial level, Beijing, Shanghai, Jiangsu, Guizhou, Yunnan, and Gansu have weak decoupling. Expansive link areas include Shanxi, Henan, Hubei, Ningxia, and Xinjiang. The other 19 provinces show expansive negative decoupling. Secondly, according to the coordination model, national carbon emissions are coordinated to the forest area. Zhejiang, Fujian, Jiangxi, and Guangdong are basically coordinated provinces. More coordinated provinces include Ningxia. The other 25 provinces are coordinated provinces. Finally, according to the comprehensive measurement model, Inner Mongolia, Qinghai, Shaanxi, Hainan, Jilin, Anhui, Liaoning, and Heilongjiang are high-quality expansive negative decoupling provinces. Chongqing, Hunan, Tianjin, Shandong, Hebei, and Guangxi are moderate to strong expansive negative decoupling provinces. This study not only provides a new perspective for analyzing forest carbon sinks, but also provides theoretical guidance for enhancing the natural carbon sink capacity, helping to achieve global carbon peak and carbon neutrality goals.