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Anthropogenic carbon emissions are increasing atmospheric carbon concentrations. Global oceans absorb about one-fourth of these emissions each year (Friedlingstein et al., 2020). Seawater’s carbon ...

Natural ecosystems, which operate as a sink, play an important role in determining the concentration of CO2 in the atmosphere and have a large storage capacity, assisting in mitigation of problem that has a negative impact on the human population. Forests are one of the most important carbon sinks in the terrestrial ecosystem, with the best example being the Western Himalaya, where healthy and sustainable vegetation is prized. Standard methodology was adopted for assessing the different parameters of carbon related information to enumerate the status of carbon storage and its trend in sustaining the ecosystem of the area. The current research displays the annual increment and carbon dynamics in various vegetation components and levels. Trees, shrubs, and herbs help to fix atmospheric carbon in a variety of forms, including AGC, BGC, and TC. The concentration of carbon-fixing potential was measured on an annual and seasonal basis, with herbs having the highest mean annual increment, followed by shrubs and trees. Pinus wallichiana had the largest annual carbon stock change among trees, followed by Cedrus deodara, Picea smithiana, and Abies pindrow. P. wallichiana topped the increase percentage with 60.58%, followed by C. deodara 33.35%, P. smithiana 5.61%, and A. pindrow 0.45%. Litter was also investigated as a potential source of mitigation, with the best results observed during the autumn months. Natural coniferous forests provide a regulating ecological service in the region by maintaining carbon dioxide levels in the form of biomass, according to the study.

Además de la cosecha de uva para consumo en fresco, elaboración de jugos y la producción de vinos, los viñedos (Vitis vinifera L.) por su condición de plantas leñosas y longevas pueden tener una participación importante en la asimilación y retención del carbono atmosférico. El objetivo de este estudio fue evaluar la tasa de intercambio neto de bióxido de carbono del ecosistema por sus siglas en inglés (NEE) en un viñedo durante su ciclo de producción, y su relación con el secuestro de carbono atmosférico. El estudio se realizó (de abril a diciembre de 2018) en un viñedo del cultivar Shiraz de 11 años, de la Vinícola San Lorenzo, Parras, Coahuila. La tasa de flujo de bióxido de carbono entre el dosel del viñedo y la atmósfera, a través de los meses de crecimiento se midió con los sensores de un sistema de covarianza eddy. De abril a noviembre el viñedo actúa como un sumidero de carbono atmosférico y durante mayo, junio y julio se tuvieron los valores mayores de NEE, con un valor promedio de -3.014 g C m-2 s-1. El carbono almacenado en la madera de las plantas del viñedo fue 3.35 t C ha-1. Estos resultados muestran que, los viñedos son sistemas agrícolas que pueden tener una participación importante en la mitigación del bióxido de carbono atmosférico, que aunado a su condición de plantas leñosas-longevas y las grandes superficies establecidas de viñedos en México y el mundo, son ecosistemas de almacenamientos de carbono muy importantes.

The atmospheric carbon dioxide (CO 2 ) mixing ratio and its carbon isotope ( δ13 C-CO 2 ) composition contain important CO 2 sink and source information spanning from ecosystem to global scales. The observation and simulation for both CO 2 and δ13 C-CO 2 can be used to constrain regional emissions and better understand the anthropogenic and natural mechanisms that control δ13 C-CO 2 variations. Such work remains rare for urban environments, especially megacities. Here, we used near-continuous CO 2 and δ13 C-CO 2 measurements, from September 2013 to August 2015, and inverse modeling to constrain the CO 2 budget and investigate the main factors that dominated δ13 C-CO 2 variations for the Yangtze River delta (YRD) region, one of the largest anthropogenic CO 2 hotspots and densely populated regions in China. We used the WRF-STILT model framework with category-specified EDGAR v4.3.2 CO 2 inventories to simulate hourly CO 2 mixing ratios and δ13 C-CO 2 , evaluated these simulations with observations, and constrained the total anthropogenic CO 2 emission. We show that (1) top-down and bottom-up estimates of anthropogenic CO 2 emissions agreed well (bias 6 %) on an annual basis, (2) the WRF-STILT model can generally reproduce the observed diel and seasonal atmospheric δ13 C-CO 2 variations, and (3) anthropogenic CO 2 emissions played a much larger role than ecosystems in controlling the δ13 C-CO 2 seasonality. When excluding ecosystem respiration and photosynthetic discrimination in the YRD area, δ13 C-CO 2 seasonality increased from 1.53 ‰ to 1.66 ‰. (4) Atmospheric transport processes in summer amplified the cement CO 2 enhancement proportions in the YRD area, which dominated monthly δs (the mixture of δ13 C-CO 2 from all regional end-members) variations. These findings show that the combination of long-term atmospheric carbon isotope observations and inverse modeling can provide a powerful constraint on the carbon cycle of these complex megacities.

Mangroves or all the plants are known to absorb the atmospheric carbon by photosynthesis. This absorbed carbon is stored in various organic forms and helps to produce the biomass. Trees dominate this process. Greater and taller is the size of the tree more is the amount of carbon fixed. Hence trees are the major plant forms to absorb maximum atmospheric carbon and biomass production. Thus, the present investigation was carried out to calculate the carbon sequestration of 12 standing mangrove tree species in Achara estuary of Sindhudurg district of Maharashtra state. The biomass and total organic carbon of standing trees is estimated by the non-destructive method. The population of Avicennia marina var. acutissima Staf. & Mold. and Rhizophora mucronata Lamk. are more in the estuary and they sequestrate about 585.70×106 and 375.10×106 lbs carbon respectively. A total of 1892.96×106 lbs of the carbon is sequestering by all the mangrove trees present in the estuary.

Urban forests help regulating flow of ecosystem services and are efficient to sequester atmospheric carbon. Tree carbon stock in urban forests and green spaces can help improving human well-being. Nagpur being one of the fastest growing urban agglomerate in India that has faced rapid loss of green spaces in last three decades. Present study assessed tree biomass carbon storage potential of a historically conserved large (67.41 ha) Seminary Hills Reserve forest of Nagpur. A total of 150 quadrats of 100 m2 were laid to understand the vegetation structure and tree biomass storage. Overall structure and composition of the forest was assessed while, non-destructive biomass estimation was carried out using tree volume eqs. A total of 27 tree species belonging to 12 plant families were observed from the forest with only 6 tree species being dominant and remaining 21 being rare in occurrence. The maximum tree carbon storage was observed in dominant tree species of Hardwickia binata (76.30 t C ha−1) followed by 17.04 t C ha−1 in Tectona grandis and 1.19 t C ha−1 in Boswellia serrata. Carbon stock in other co-dominant species was reported in Terminalia bellirica (76.57 kg C ha−1), Gardenia resinifera (1118.6 g C ha−1) and Terminalia arjuna (84.8 g C ha−1). Total carbon stock of dominant tree species present in Seminary Hills urban forest was 94.53 ± 39.6 t C ha−1. The study intends to bring focus ecosystem benefits from Urban Forests in growing urban sprawls of India and the need to include their vital role in urban planning.

Chemistry transport models (CTMs) play an important role in understanding fluxes and atmospheric distribution of carbon dioxide (CO2). They have been widely used for modeling CO2 transport through forward simulations and inferring fluxes through inversion systems. With the increasing availability of high-resolution observations, it has been become possible to estimate CO2 fluxes at higher spatial resolution. In this work, we implemented CO2 transport in the Model for Prediction Across Scales – Atmosphere (MPAS-A). The objective is to use the variable-resolution capability of MPAS-A to enable a high-resolution CO2 simulation in a limited region with a global model. Treating CO2 as an inert tracer, we implemented in MPAS-A (v6.3) the CO2 transport processes, including advection, vertical mixing by boundary layer scheme, and convective transport. We first evaluated the newly implemented model's tracer mass conservation and then its CO2 simulation accuracy. A 1-year (2014) MPAS-A simulation is evaluated at the global scale using CO2 measurements from 50 near-surface stations and 18 Total Carbon Column Observing Network (TCCON) stations. The simulation is also compared with two global models: National Oceanic and Atmospheric Administration (NOAA) CarbonTracker v2019 (CT2019) and European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS). A second set of simulation (2016–2018) is used to evaluate MPAS-A at regional scale using Atmospheric Carbon and Transport – America (ACT-America) aircraft CO2 measurements over the eastern United States. This simulation is also compared with CT2019 and a 27 km WRF-Chem simulation. The global-scale evaluations show that MPAS-A is capable of representing the spatial and temporal CO2 variation with a comparable level of accuracy as IFS of similar horizontal resolution. The regional-scale evaluations show that MPAS-A is capable of representing the observed atmospheric CO2 spatial structures related to the midlatitude synoptic weather system, including the warm versus cold sector distinction, boundary layer to free troposphere difference, and frontal boundary CO2 enhancement. MPAS-A's performance in representing these CO2 spatial structures is comparable to the global model CT2019 and regional model WRF-Chem.

The soil organic carbon (SOC) pool is larger than the biotic and atmospheric carbon pools, and understanding cultivated land SOC is critical for evaluating soil fertility and local agricultural man...

Treed peatlands exhibit both crown and smouldering fire potential; however, neither are included in Canadian wildfire management models and, as such, they are not formally represented in management decision-making. The lack of smouldering fire risk assessment is a critical research gap as these fires can represent heavy resource draws and are predominant sources of smoke, air pollutants and atmospheric carbon. Here, for the first time, we combine existing knowledge of the controls on smouldering peat fire with expert opinion-based weightings through a multi-criteria decision analysis, to map the smouldering fire potential (i.e. hazard) of treed peatlands in the Boreal Plains, Alberta, Canada. We find that smouldering potential varies considerably between treed peatlands and that areas of sparser peatland coverage may contain high smouldering-potential peatlands. Further, we find that treed peatlands are a common feature in the wildland–human interface and that proportionally, the area of high smouldering potential is greater closer to roads compared with farther away. Our approach enables a quantitative measure of smouldering fire potential and evidences the need to incorporate peatland–wildfire interactions into wildfire management operations. We suggest that similar frameworks could be used in other peatland dominated regions as part of smouldering fire risk assessments.

The sixth phase of the Coupled Model Intercomparison Project (CMIP6) is the latest modeling effort for general circulation models to simulate and project various aspects of climate change. Many of the general circulation models (GCMs) participating in CMIP6 provide archived output that can be used to calculate effective climate sensitivity (ECS) and forecast future temperature change based on emissions scenarios from several Shared Socioeconomic Pathways (SSPs). Here we use our multiple linear regression energy balance model, the Empirical Model of Global Climate (EM-GC), to simulate and project changes in global mean surface temperature (GMST), calculate ECS, and compare to results from the CMIP6 multi-model ensemble. An important aspect of our study is a comprehensive analysis of uncertainties due to radiative forcing of climate from tropospheric aerosols (AER RF) in the EM-GC framework. We quantify the attributable anthropogenic warming rate (AAWR) from the climate record using the EM-GC and use AAWR as a metric to determine how well CMIP6 GCMs replicate human-driven global warming over the last 40 years. The CMIP6 multi-model ensemble indicates a median value of AAWR over 1975–2014 of 0.221 ∘C per decade (range of 0.151 to 0.299 ∘C per decade; all ranges given here are for 5th and 95th confidence intervals), which is notably faster warming than our median estimate for AAWR of 0.157 ∘C per decade (range of 0.120 to 0.195 ∘C per decade) inferred from the analysis of the Hadley Centre Climatic Research Unit version 5 data record for GMST. Estimates of ECS found using the EM-GC assuming that climate feedback does not vary over time (best estimate 2.33 ∘C; range of 1.40 to 3.57 ∘C) are generally consistent with the range of ECS of 1.5 to 4.5 ∘C given by the IPCC's Fifth Assessment Report. The CMIP6 multi-model ensemble exhibits considerably larger values of ECS (median 3.74 ∘C; range of 2.19 to 5.65 ∘C). Our best estimate of ECS increases to 3.08 ∘C (range of 2.23 to 5.53 ∘C) if we allow climate feedback to vary over time. The dominant factor in the uncertainty for our empirical determinations of AAWR and ECS is imprecise knowledge of AER RF for the contemporary atmosphere, though the uncertainty due to time-dependent climate feedback is also important for estimates of ECS. We calculate the likelihood of achieving the Paris Agreement target (1.5 ∘C) and upper limit (2.0 ∘C) of global warming relative to pre-industrial for seven of the SSPs using both the EM-GC and the CMIP6 multi-model ensemble. In our model framework, SSP1-2.6 has a 53 % probability of limiting warming at or below the Paris target by the end of the century, and SSP4-3.4 has a 64 % probability of achieving the Paris upper limit. These estimates are based on the assumptions that climate feedback has been and will remain constant over time since the prior temperature record can be fit so well assuming constant climate feedback. In addition, we quantify the sensitivity of future warming to the curbing of the current rapid growth of atmospheric methane and show that major near-term limits on the future growth of methane are especially important for achievement of the 1.5 ∘C goal of future warming. We also quantify warming scenarios assuming climate feedback will rise over time, a feature common among many CMIP6 GCMs; under this assumption, it becomes more difficult to achieve any specific warming target. Finally, we assess warming projections in terms of future anthropogenic emissions of atmospheric carbon. In our model framework, humans can emit only another 150±79 Gt C after 2019 to have a 66 % likelihood of limiting warming to 1.5 ∘C and another 400±104 Gt C to have the same probability of limiting warming to 2.0 ∘C. Given the estimated emission of 11.7 Gt C per year for 2019 due to combustion of fossil fuels and deforestation, our EM-GC simulations suggest that the 1.5 ∘C warming target of the Paris Agreement will not be achieved unless carbon and methane emissions are severely curtailed in the next 10 years.

In the context of climate change, there is an urgent need for rapid and efficient methods to capture and sequester carbon from the atmosphere. For instance, production, use and storage of biochar are highly carbon negative, resulting in an estimated sequestration of 0.3–2 Gt CO2 year−1 by 2050. Yet, biochar production requires more knowledge on feedstocks, thermochemical conversion and end applications. Herein, we review the design and development of biochar systems, and we investigate the carbon removal industry. Carbon removal efforts are currently promoted via the voluntary market. The major commercialized technologies for offering atmospheric carbon removal are forestation, direct air carbon capture utilization and storage, soil carbon sequestration, wooden building elements and biochar, with corresponding fees ranging from 10 to 895 GBP (British pounds) per ton CO2. Biochar fees range from 52 to 131 GBP per ton CO2, which indicates that biochar production is a realistic strategy that can be deployed at large scale. Carbon removal services via biochar are currently offered through robust marketplaces that require extensive certification, verification and monitoring, which adds an element of credibility and authenticity. Biochar eligibility is highly dependent on the type of feedstock utilized and processing conditions employed. Process optimization is imperative to produce an end product that meets application-specific requirements, environmental regulations and achieve ultimate stability for carbon sequestration purposes.

The present study investigates the response of the high-latitude carbon cycle to changes in atmospheric greenhouse gas (GHG) concentrations in idealized climate change scenarios. To this end we use an adapted version of JSBACH – the land surface component of the Max Planck Institute for Meteorology Earth System Model (MPI-ESM) – that accounts for the organic matter stored in the permafrost-affected soils of the high northern latitudes. The model is run under different climate scenarios that assume an increase in GHG concentrations, based on the Shared Socioeconomic Pathway 5 and the Representative Concentration Pathway 8.5, which peaks in the years 2025, 2050, 2075 or 2100, respectively. The peaks are followed by a decrease in atmospheric GHGs that returns the concentrations to the levels at the beginning of the 21st century, reversing the imposed climate change. We show that the soil CO2 emissions exhibit an almost linear dependence on the global mean surface temperatures that are simulated for the different climate scenarios. Here, each degree of warming increases the fluxes by, very roughly, 50 % of their initial value, while each degree of cooling decreases them correspondingly. However, the linear dependence does not mean that the processes governing the soil CO2 emissions are fully reversible on short timescales but rather that two strongly hysteretic factors offset each other – namely the net primary productivity and the availability of formerly frozen soil organic matter. In contrast, the soil methane emissions show a less pronounced increase with rising temperatures, and they are consistently lower after the peak in the GHG concentrations than prior to it. Here, the net fluxes could even become negative, and we find that methane emissions will play only a minor role in the northern high-latitude contribution to global warming, even when considering the high global warming potential of the gas. Finally, we find that at a global mean temperature of roughly 1.75 K (±0.5 K) above pre-industrial levels the high-latitude ecosystem turns from a CO2 sink into a source of atmospheric carbon, with the net fluxes into the atmosphere increasing substantially with rising atmospheric GHG concentrations. This is very different from scenario simulations with the standard version of the MPI-ESM, in which the region continues to take up atmospheric CO2 throughout the entire 21st century, confirming that the omission of permafrost-related processes and the organic matter stored in the frozen soils leads to a fundamental misrepresentation of the carbon dynamics in the Arctic.

Wind energy is considered one of the cleanest and most sustainable resources among renewable energy sources. However, several negative environmental impacts can be observed, unless suitable sites are selected for the establishment of wind farms. The aim of this study is to determine the change in the soil organic carbon (SOC) stock resulting from land cover changes that were caused by wind farm establishments in the Karaburun peninsula. Within the scope of the study, remote sensing and geographic information system technologies were utilized. Maximum likelihood algorithm, one of the supervised classification techniques, was used to classify the land cover, and Normalized Difference Vegetation Index (NDVI) analyses were performed to determine land cover changes. The findings were correlated with the "Turkey Soil Organic Carbon Project" data. As a result, depending on the establishment of wind farms in the Karaburun Peninsula, a total decrease of 18,330.57 tons of SOC in the study area between 2000 and 2019 was determined. It should be taken into consideration that besides many other negative effects (effects on human health, effects on the ecosystem, effects on animals, etc.), land cover changes caused by wind farms may indirectly cause important problems such as climate change. Recently, this situation shows that there is an important dilemma in terms of current implementations. Wind farms are the most invested renewable energy sources and alternative energy supply to fossil fuels in terms of preventing climate change. However, the results of this study have reviewed that lack of proper approaches and methods to establish wind farms may result in various problems such as physical, chemical, and biological degradations and an increase in the amount of atmospheric carbon. Consequently, the investments in renewable energy sources should be comprehensively reevaluated in terms of current technologies, quality in the scope of environmental impact assessment and strategic environmental assessment processes, legal regulations and national policies, long-term environmental costs, etc.

Since the 1950's the Earth's natural carbon cycle has not sufficiently sequestrated excess atmospheric CO2 contributed by human activities. CO2 levels rose above 400 ppm in 2013 and are forecasted to exceed 500 ppm by 2070, a level last experienced during the Paleogene period 25–65 MYA. While humanity benefits from the extraction and combustion of carbon from Earth's crust, we have overlooked the impact on global climate change. Here, we present a strategy to mine atmospheric carbon to mitigate CO2 emissions and create economically lucrative green products. We employ an artificial carbon cycle where agricultural plants capture CO2 and the carbon is transformed into silicon carbide (SiC), a valuable commercial material. By carefully quantifying the process we show that 14% of plant-sequestered carbon is stored as SiC and estimate the scale needed for this process to have a global impact.

The accumulation of carbon of organic matter by forest phytocenoses during photosynthesis is their most important function, mitigating climate change on the Earth. The literature provides data that the territory of the Russian Federation is a large sink of atmospheric carbon. However, the estimates of the sink, as well as the values ​​of the net primary production (NPP) of forest ecosystems, vary widely. This paper presents materials describing the net carbon production of phytomass in pine forests of different types of growing conditions in the northern and middle taiga of the Komi Republic. Premature, mature, and old-growth pine forests of green moss, lichen, and sphagnum types have been studied at forest stations. The carbon sequestration by the forest stand is assessed by biological productivity using sample trees. The regression equations for the dependence of the increments of individual organs of a sample tree on the stem diameter at a height of 1.3 m are composed. A statistically significant relationship is found between these parameters, characterized by high trend approximation values ​​varying from 0.44 to 0.99 (at 95% significance level). It is calculated that, under the conditions of the European Russian northeast, the NPP of carbon in pine phytocenoses varies within the range of 1.9–4.5 t C ha–1 year–1. It is established that the tree stand accounts for 32–73% of the total NPP. With increasing soil moisture and moving northward, the participation of plants in the ground vegetation increases in the total NPP. It is noted that a significant part of the NPP of carbon of the tree layer of pine forests is formed by the photosynthetic apparatus and the stem wood. Based on these data, the conversion relations between NPP and wood volume/carbon stock in the stand for pine forests of the northern and middle taiga are derived.

Emissions from biomass burning (BB) are a key source of atmospheric tracer gases that affect the atmospheric carbon cycle. We developed four sets of global BB emissions estimates (named GlcGlob, GlcGeoc, McdGlob, and McdGeoc) using a bottom-up approach and by combining the remote sensing products related to fire distribution with two aboveground biomass (AGB) and two land cover classification (LCC) distributions. The sensitivity of the estimates of BB emissions to the AGB and LCC data was evaluated using the carbon monoxide (CO) emissions associated with each BB estimate. Using the AGB and/or LCC data led to substantially different spatial estimates of CO emissions, with a large (factor of approximately 3) spread of estimates for the mean annual CO emissions: 526±53, 219±35, 624±57, and 293±44 Tg CO yr−1 for GlcGlob, GlcGeoc, McdGlob, and McdGeoc, respectively, and 415±47 Tg CO yr−1 for their ensemble average (EsmAve). We simulated atmospheric CO variability at an approximately 2.5∘ grid using an atmospheric tracer transport model and the BB emissions estimates and compared it with ground-based and satellite observations. At ground-based observation sites during fire seasons, the impact of intermittent fire events was poorly defined in our simulations due to the coarse resolution, which obscured temporal and spatial variability in the simulated atmospheric CO concentration. However, when compared at the regional and global scales, the distribution of atmospheric CO concentrations in the simulations shows substantial differences among the estimates of BB emissions. These results indicate that the estimates of BB emissions are highly sensitive to the AGB and LCC data.

Climate change is the severest environmental threat of the 21st century. The main factor responsible for the current pace of climate change is attributed to anthropogenic emission of greenhouse gases (GHGs), mainly carbon-dioxide (CO2). So, the aim of reducing carbon sources and increasing the carbon sink can be achieved by protecting the carbon pools. Forests are the largest carbon pool on earth as they hold more than 80% of all terrestrial above ground carbon (AGC) and more than 70% of all soil organic carbon (SOC). Therefore, forests are found to play a key role in the emission mitigation by sequestrating the atmospheric carbon into biomass and soil, and it plays an important role in the global carbon cycle. This article is focused on to understand the carbon sequestration potential of disturbed and undisturbed/managed forest ecosystems due to community interventions which could have a significant contribution against global climate change. It concludes that managed/undisturbed forests are the most effective and consistent sinks of GHGs compared to unmanaged forests. Besides the forest biomass, forests soils also have the potential to slow down the rate of atmospheric CO2 enrichment through the process of carbon sequestration. Therefore, proper and systematic management of forests can store a huge amount of carbon, contribute to mitigate climate change, and help to achieve the required goal of emission reduction as per Kyoto Protocol. Hence, further research is needed to develop a better understanding on the impacts of disturbances on carbon sequestration of the forests ecosystem. Key words: Biomass, carbon pools, carbon sequestration, climate change, forests, greenhouse gases.

Carbon sequestration describes long-term storage of carbon dioxide or other forms of carbon to either mitigate or defer global warming and avoid dangerous climate change. Present study deals with the absorption of the atmospheric carbon in the study area selected by selecting planting methods that return biomass to the soil and enhance the conditions in which the carbon within the plants will be reduced to its elemental nature and stored in a stable state through Green belts. It is calculated that, Carbon Absorption by Green Belt Carbon absorption rate is approximated 49.27 kg per mature plant per year as per international standards. As per CPCB (2000) Guidelines, the trees to be planted are 1250 plants per acre, 1250 trees will absorb 1250 X 49.27 = 61587.50 kg of carbon per year per Acer. Project Site (Pench I & II - 1.16 acre) has sequestered 18724 kg of carbon per Acre.

Autotrophic carbon dioxide (CO2) fixation by microbes is ubiquitous in the environment and potentially contributes to the soil organic carbon (SOC) pool. However, the multiple autotrophic pathways of microbial carbon assimilation and fixation in paddy soils remain poorly characterized. In this study, we combine metagenomic analysis with 14C‐labelling to investigate all known autotrophic pathways and CO2 assimilation mechanisms in five typical paddy soils from southern China. Marker genes of six autotrophic pathways are detected in all soil samples, which are dominated by the cbbL genes (67%–82%) coding the ribulose‐bisphosphate carboxylase large chain in the Calvin cycle. These marker genes are associated with a broad range of phototrophic and chemotrophic genera. Significant amounts of 14C‐CO2 are assimilated into SOC (74.3–175.8 mg 14C kg−1) and microbial biomass (5.2–24.1 mg 14C kg−1) after 45 days incubation, where more than 70% of 14C‐SOC was concentrated in the relatively stable humin fractions. These results show that paddy soil microbes contain the genetic potential for autotrophic carbon fixation spreading over broad taxonomic ranges, and can incorporate atmospheric carbon into organic components, which ultimately contribute to the stable SOC pool.

Climate change is defined as the shift in climate patterns mainly caused by greenhouse gas emissions from natural systems and human activities. So far, anthropogenic activities have caused about 1.0 °C of global warming above the pre-industrial level and this is likely to reach 1.5 °C between 2030 and 2052 if the current emission rates persist. In 2018, the world encountered 315 cases of natural disasters which are mainly related to the climate. Approximately 68.5 million people were affected, and economic losses amounted to $131.7 billion, of which storms, floods, wildfires and droughts accounted for approximately 93%. Economic losses attributed to wildfires in 2018 alone are almost equal to the collective losses from wildfires incurred over the past decade, which is quite alarming. Furthermore, food, water, health, ecosystem, human habitat and infrastructure have been identified as the most vulnerable sectors under climate attack. In 2015, the Paris agreement was introduced with the main objective of limiting global temperature increase to 2 °C by 2100 and pursuing efforts to limit the increase to 1.5 °C. This article reviews the main strategies for climate change abatement, namely conventional mitigation, negative emissions and radiative forcing geoengineering. Conventional mitigation technologies focus on reducing fossil-based CO2 emissions. Negative emissions technologies are aiming to capture and sequester atmospheric carbon to reduce carbon dioxide levels. Finally, geoengineering techniques of radiative forcing alter the earth’s radiative energy budget to stabilize or reduce global temperatures. It is evident that conventional mitigation efforts alone are not sufficient to meet the targets stipulated by the Paris agreement; therefore, the utilization of alternative routes appears inevitable. While various technologies presented may still be at an early stage of development, biogenic-based sequestration techniques are to a certain extent mature and can be deployed immediately.

The objective of this paper is to formulate suitable policies and management practices that can firmly reduce CO2–C (carbon dioxide –carbon) emissions and sequester it in a sustainable way. Land use and management practices can influence both efflux and influx of carbon between soil and the atmosphere. Organic matter dynamics and nutrient cycling in the soil are closely related to nutrient immobilization and mineralization. Unplanned conversion of lands to agricultural production causes a sharp decrease in carbon stored in soil. In the atmosphere, 4.0 Gt C yr-1 is enriched by different sources. Increasing soil organic carbon (SOC) improves soil health and mitigate climate change. Histosol, clayey and fine particle size have good capacity to sequestrate C in soil. Land use pattern controls organic matter status in soil. Crop/grass, forestry/agroforestry, reduced tillage, quality of organic matter, soil biotic - abiotic are the major factors to sequestrate significant C in soil. The application of fertilizers especially nitrogen usually results in an increase in crop growth as well as a corresponding increase in root development takes place for building up active organicmatter in soil. Biochar amendments can impact soil C storage and net CO2 removals from the atmosphere in three different ways such as longer residence time due to resistant to microbial decay, plant productivity and reduce N2O emission. Wetland soil, effective management practices and control deforestation sequestrate 0.2, 2.0 and 1.6 Gt C yr-1, respectively. Based on these information, it is possible to increase 4‰ carbon a year the quantity of carbon contained in soils at 0-40 cm soil depth to halt carbon dioxide enrichment (4.0 Gt C yr-1) in the atmosphere.

With respect to their role in the global carbon cycle, natural peatlands are characterized by their ability to sequester atmospheric carbon. This trait is strongly connected to the water regime of these ecosystems. Large parts of the soil profile in natural peatlands are water saturated, leading to anoxic conditions and to a diminished decomposition of plant litter. In functioning peatlands, the rate of carbon fixation by plant photosynthesis is larger than the decomposition rate of dead organic material. Over time, the amount of carbon that remains in the soil and is not converted back to carbon dioxide grows. Land use of peatlands often goes along with water level manipulations and thereby with alterations of carbon flux dynamics. In this study, carbon dioxide ( CO2 ) and methane ( CH4 ) flux measurements from a bog site in northwestern Germany that has been heavily degraded by peat mining are presented. Two contrasting types of management have been implemented at the site: (1) drainage during ongoing peat harvesting on one half of the central bog area and (2) rewetting on the other half that had been taken out of use shortly before measurements commenced. The presented 2-year data set was collected with an eddy covariance (EC) system set up on a central railroad dam that divides the two halves of the (former) peat harvesting area. We used footprint analysis to split the obtained CO2 and CH4 flux time series into data characterizing the gas exchange dynamics of both contrasting land use types individually. The time series gaps resulting from data division were filled using the response of artificial neural networks (ANNs) to environmental variables, footprint variability, and fuzzy transformations of seasonal and diurnal cyclicity. We used the gap-filled gas flux time series from 2 consecutive years to evaluate the impact of rewetting on the annual vertical carbon balances of the cutover bog. Rewetting had a considerable effect on the annual carbon fluxes and led to increased CH4 and decreased CO2 release. The larger relative difference between cumulative CO2 fluxes from the rewetted ( 13±6 mol m −2 a −1 ) and drained ( 22±7 mol m −2 a −1 ) section occurred in the second observed year when rewetting apparently reduced CO2 emissions by 40 %. The absolute difference in annual CH4 flux sums was more similar between both years, while the relative difference of CH4 release between the rewetted ( 0.83±0.15 mol m −2 a −1 ) and drained ( 0.45±0.11 mol m −2 a −1 ) section was larger in the first observed year, indicating a maximum increase in annual CH4 release of 84 % caused by rewetting at this particular site during the study period.

In order to address concerns related to global warming and increased atmospheric carbon content, the life cycle assessment (LCA) tool has demonstrated usefulness in the building and construction sector. The LCA is used to evaluate environmental impacts concerning all stages of the building process from pcradleq to pgraveq. The LCA helps to promote sustainable development by considering environmental indicators such as stratospheric ozone depletion, eutrophication, global warming potential, and many more. It is of an interest to know the degree of impact on a given environmental indicator if an input is changed in terms of the type or amount of the materials used. The LCA software Athena IE4B was employed to analyze data of a selected timber building. This study is aimed at evaluating the sensitivity of LCA analysis on a hybrid timber building, which was done via two case studies. Case 1 focused on changes in the volume of wood materials, meanwhile Case 2 focused on simultaneous changes in the volume of materials for wood, steel, and concrete. In Case 1, it was observed increasing wood materials increased environmental indicators, with stratospheric ozone depletion being the most sensitive and global warming potential as the least sensitive. On the other hand, Case 2 discovered that proportionally increasing wood materials in relation to steel and concrete materials decreased environmental indicators, with eutrophication being the most sensitive and stratospheric ozone depletion as the least sensitive. This study helped support the feasibility of using Athena IE4B for LCA analysis in the initial assessment of a building.

Regenerative agriculture is both an attitude and a suite of practices that restores and maintains soil health and fertility, supports biodiversity, protects watersheds, and improves ecological and economic resilience. It focuses on creating the conditions for life above and below ground and takes its cues from nature, which has a very long track record of successfully growing things. By re‐carbonizing soils via photosynthesis and biology, particularly on degraded land, regenerative agriculture can also sequester increasing quantities of atmospheric carbon (CO2) underground, making it a low‐cost “shovel‐ready” solution to climate change. Its multiple co‐benefits, including the production of healthy, nutritious food, means it will be a critical component of our response to rising climate instability.

In the present century, there has been increasing global pressure on governments to implement policies to incentivize reductions in CO2 emissions based on the devastating effects of global climate change. Researchers generally have established the fact that the automobile sector generates more than 50% of the atmospheric carbon concentration. It has also become obvious that FCC-Abuja Nigeria is merely a replica of Lagos transport-wise in all ramifications. The Abuja master plan as of 1979 specifically recommended the development of mass transport by light-rail when the city’s inhabitants are about 1.6 and 3.1 million for airport. The non-implementation of the light rail in the city has aggravated the flood of vehicular traffic that generates a lot of Green House Gas that in turn swells up the city’s ambient temperature. This research therefore used the handheld outdoor thermometer to measure the traffic corridors in Abuja in relation to the WHO and FEPA tolerance threshold standard. This is compared with the modern electric rail that is environmentally friendly, and the result reveals that the present transport system in the city negates the global crusade for Green Mobility. It is therefore recommended that the Federal Government of Nigeria should as a matter of urgency cease from her lip-service to the global SDGs and fully implements the overdue Abuja light rail that will positively woo the other cities of the federation. Key words: Atmospheric temperature, climate change, mass-transit, light-rail, transportation.

Mitigating climate change requires clean energy and the removal of atmospheric carbon. Building soil carbon is an appealing way to increase carbon sinks and reduce emissions owing to the associated benefits to agriculture. However, the practical implementation of soil carbon climate strategies lags behind the potential, partly because we lack clarity around the magnitude of opportunity and how to capitalize on it. Here we quantify the role of soil carbon in natural (land-based) climate solutions and review some of the project design mechanisms available to tap into the potential. We show that soil carbon represents 25% of the potential of natural climate solutions (total potential, 23.8 Gt of CO2-equivalent per year), of which 40% is protection of existing soil carbon and 60% is rebuilding depleted stocks. Soil carbon comprises 9% of the mitigation potential of forests, 72% for wetlands and 47% for agriculture and grasslands. Soil carbon is important to land-based efforts to prevent carbon emissions, remove atmospheric carbon dioxide and deliver ecosystem services in addition to climate mitigation. Diverse strategies are needed to mitigate climate change. This study finds that storing carbon in soils represents 25% of land-based potential, of which 60% must come from rebuilding depleted carbon stores.

This article takes on the political and contested nature of forest carbon accounting via three “points of engagement” that articulate forest carbon initiatives as representations of tradable carbon. The three points of engagement—(1) baseline determinations, (2) the calculation of additionality, and (3) the role of uncertainty—are used to show how processes framed as technical are often spaces where uneven social and political interests are manipulated or obscured and contribute to varying environmental and conservation outcomes. The article begins by reviewing how carbon counting emerges in critical social science literature on forest carbon projects. Next, it explains carbon accounting broadly, the specifics of forest carbon accounting and why forests are popular spaces for financialized carbon sequestration. It concludes by arguing that carbon accounting is an uneven technical and political process that makes multiples forms of carbon legible on financial markets but does little to physically address atmospheric carbon concentrations.

Global recognition of climate change and its predicted consequences has created the need for practical management strategies for increasing the ability of natural ecosystems to capture and store atmospheric carbon. Mangrove forests, saltmarshes and seagrass meadows, referred to as blue carbon ecosystems (BCEs), are hotspots of atmospheric CO2 storage due to their capacity to sequester carbon at a far higher rate than terrestrial forests. Despite increased effort to understand the mechanisms underpinning blue carbon fluxes, there has been little synthesis of how management activities influence carbon stocks and greenhouse gas (GHG) fluxes in BCEs. Here, we present a global meta-analysis of 111 studies that measured how carbon stocks and GHG fluxes in BCEs respond to various coastal management strategies. Research effort has focused mainly on restoration approaches, which resulted in significant increases in blue carbon after 4 years compared to degraded sites, and the potential to reach parity with natural sites after 7-17 years. Lesser studied management alternatives, such as sediment manipulation and altered hydrology, showed only increases in biomass and weaker responses for soil carbon stocks and sequestration. The response of GHG emissions to management was complex, with managed sites emitting less than natural reference sites but emitting more compared to degraded sites. Individual GHGs also differed in their responses to management. To date, blue carbon management studies are underrepresented in the southern hemisphere and are usually limited in duration (61% of studies

Rivers are a major source of nutrients, carbon and alkalinity to the global ocean. In this study, we firstly estimate pre-industrial riverine loads of nutrients, carbon and alkalinity based on a hierarchy of weathering and terrestrial organic matter export models, while identifying regional hotspots of the riverine exports. Secondly, we implement the riverine loads into a global ocean biogeochemical model to describe their implications for oceanic nutrient concentrations, net primary production (NPP) and air–sea CO2 fluxes globally, as well as in an analysis of coastal regions. Thirdly, we quantitatively assess the terrestrial origins and the long-term fate of riverine carbon in the ocean. We quantify annual bioavailable pre-industrial riverine loads of 3.7 Tg P, 27 Tg N, 158 Tg Si and 603 Tg C delivered to the ocean globally. We thereby identify the tropical Atlantic catchments (20 % of global C), Arctic rivers (9 % of global C) and Southeast Asian rivers (15 % of global C) as dominant suppliers of carbon for the ocean. The riverine exports lead to a simulated net global oceanic CO2 source of 231 Tg C yr−1 to the atmosphere, which is mainly caused by inorganic carbon (source of 183 Tg C yr−1) and by organic carbon (source of 128 Tg C yr−1) riverine loads. Additionally, a sink of 80 Tg C yr−1 is caused by the enhancement of the biological carbon uptake from dissolved inorganic nutrient inputs from rivers and the resulting alkalinity production. While large outgassing fluxes are simulated mostly in proximity to major river mouths, substantial outgassing fluxes can be found further offshore, most prominently in the tropical Atlantic. Furthermore, we find evidence for the interhemispheric transfer of carbon in the model; we detect a larger relative outgassing flux (49 % of global riverine-induced outgassing) in the Southern Hemisphere in comparison to the hemisphere's relative riverine inputs (33 % of global C inputs), as well as an outgassing flux of 17 Tg C yr−1 in the Southern Ocean. The addition of riverine loads in the model leads to a strong NPP increase in the tropical west Atlantic, Bay of Bengal and the East China Sea (+166 %, +377 % and +71 %, respectively). On the light-limited Arctic shelves, the NPP is not strongly sensitive to riverine loads, but the CO2 flux is strongly altered regionally due to substantial dissolved inorganic and organic carbon supplies to the region. While our study confirms that the ocean circulation remains the main driver for biogeochemical distributions in the open ocean, it reveals the necessity to consider riverine inputs for the representation of heterogeneous features in the coastal ocean and to represent riverine-induced pre-industrial carbon outgassing in the ocean. It also underlines the need to consider long-term CO2 sources from volcanic and shale oxidation fluxes in order to close the framework's atmospheric carbon budget.

Throughout Earth’s history, variations in atmospheric CO2 concentration modulated climate. Understanding changes in atmospheric carbon cycle is therefore pivotal in predicting consequences of recent global warming. Here, we report stable carbon isotopes (δ13C) of molecular land plant fossils complemented by bulk organic and inorganic carbon fractions for early Toarcian (Early Jurassic) sediments that coincided with global warming and a carbon cycle perturbation. The carbon cycle perturbation is expressed by a negative excursion in the δ13C records established for the different substrates. Based on differences in the magnitude of the carbon isotope excursion recorded in land plants and marine substrates we infer that the early Toarcian warming was paralleled by an increase in atmospheric CO2 levels from ~500 ppmv to ~1000 ppmv. Our data suggest that rising atmospheric CO2 levels resulted from the injection of 12C-enriched methane and its subsequent oxidation to CO2. Based on the cyclic nature of the CIE we concluded that methane was released from climate sensitive reservoirs, in particular permafrost areas. Moderate volcanic CO2 emissions led to a destabilization of the labile permafrost carbon pool triggering the onset of Toarcian climate change only. The main carbon cycle perturbation then subsequently was driven by a self-sustained demise of a carbon-rich cryosphere progressing from mid to high latitudes as reflected by latitudinal climate gradients recorded in land plant carbon isotopes.

Improved crop–fallow systems in the humid tropics can simultaneously sequester atmospheric carbon emissions and contribute to sustainable livelihoods of rural populations. A study with an indigenous community in eastern Panama revealed a considerable biophysical potential for carbon offsets in small-scale slash-and-burn agriculture through longer fallow periods, improved fallow management, secondary forest development, and agricultural intensification. Based on soil and biomass carbon measurements, estimated annual sequestration rates amount to 0.3−3.7 t C ha − 1 yr − 1 . Despite such potential, the economic benefits of initiatives aimed at sequestration of carbon in the community are likely to be rather unequally distributed within the community. Heterogeneity in livelihood strategies and uneven asset endowments among households – factors often overlooked in the ongoing carbon and sustainable development debate – are expected to strongly affect household participation. Indeed, only the better-endowed households that have also managed to diversify into more lucrative farm and non-farm activities are likely to be able to participate in and thus benefit from improved crop–fallow systems that capture carbon. Economic, ethical, institutional, and technical concerns need to be taken into account when designing community carbon management and investment plans.

Carbon isotope discrimination (Δ13C) in C3 woody plants is a key variable for the study of photosynthesis. Yet how Δ13C varies at decadal scales, and across regions, and how it is related to gross primary production (GPP), are still incompletely understood. Here we address these questions by implementing a new Δ13C modelling capability in the land-surface model JULES incorporating both photorespiratory and mesophyll-conductance fractionations. We test the ability of four leaf-internal CO2 concentration models embedded in JULES to reproduce leaf and tree-ring (TR) carbon isotopic data. We show that all the tested models tend to overestimate average Δ13C values, and to underestimate interannual variability in Δ13C. This is likely because they ignore the effects of soil water stress on stomatal behavior. Variations in post-photosynthetic isotopic fractionations across species, sites and years, may also partly explain the discrepancies between predicted and TR-derived Δ13C values. Nonetheless, the “least-cost” (Prentice) model shows the lowest biases with the isotopic measurements, and lead to improved predictions of canopy-level carbon and water fluxes. Overall, modelled Δ13C trends vary strongly between regions during the recent (1979–2016) historical period but stay nearly constant when averaged over the globe. Photorespiratory and mesophyll effects modulate the simulated global Δ13C trend by 0.0015±0.005‰ and –0.0006±0.001‰ ppm−1, respectively. These predictions contrast with previous findings based on atmospheric carbon isotope measurements. Predicted Δ13C and GPP tend to be negatively correlated in wet-humid and cold regions, and in tropical African forests, but positively related elsewhere. The negative correlation between Δ13C and GPP is partly due to the strong dominant influences of temperature on GPP and vapor pressure deficit on Δ13C in those forests. Our results demonstrate that the combined analysis of Δ13C and GPP can help understand the drivers of photosynthesis changes in different climatic regions.

Biochar is a carbon-rich solid formed from the organic residue by pyrolysis. The productivity of biochar relies on feedstock type and pyrolysis conditions. Studies on biochar were discussed relating its application and production as a source of soil remediation and bioeconomy. Pyrolysis conditions, gasification, hydrothermal carbonization were discussed in this study in obtaining biochar for remediation of soil. Biochar have made substantial breakthroughs in reducing greenhouse gas emissions and global warming, reducing soil nutrient leaching losses, sequester atmospheric carbon into the soil, increasing agricultural productivity, reducing bioavailability of environmental contaminants and subsequently, becoming a value-added product sustaining bioeconomy. Bio-economy implies the exploration and exploitation of bio-resources, which involves the use of biotechnology to create new bio-products of economic value. Biochar is a marketable bio-product, which can be used in agriculture, industries and energy sector. Thus, biochar production can enhance soil property and provide opportunities for additional income. This review presents the production, agronomic and economic benefits of biochar. Keywords: Pyrolysis, Feedstock, Bio-economy, Soil remediation, Biochar

International audience; We present observations of local enhancements in carbon dioxide (CO2) from local emissions sources over three eastern US regions during four deployments of the Atmospheric Carbon TransportAmerica (ACT-America) campaign between summer 2016 and spring 2018. Local CO2 emissions werecharacterized by carbon monoxide (CO) to CO2 enhancement ratios (i.e., ΔCO/ΔCO2 ) in air mass mixing observed during aircraft transects within the planetary boundary layer. By analyzing regional-scale variability of CO2 enhancements as a function of ΔCO/ΔCO2 enhancement ratios, observed relative contributions to CO2 emissions were separated into fossil fuel and biomass burning (BB) regimes across regions and seasons. CO2 emission contributions attributed to biomass burning (ΔCO/ΔCO2 > 4%) were negligible during summer and fall in all regions but climbed to ∼9%–11% of observed combustion contributions in the South during winter and spring. Relative CO2 fire emission trends matched observed winter and spring BB contributions,but conflictingly predicted similar levels of BB during the fall. Satellite fire data from MODIS and VIIRS suggested the use of higher spatial resolution fire data that might improve modeled BB emissions but were not able to explain the bulk of the discrepancy

In a climate and land use change context, the sequestration of atmospheric carbon in urban agglomeration is key to achieving carbon emission and neutrality targets. It is thus critical to understand how various climate and land use changes impact overall carbon sequestration in large-scale city circle areas. As the largest urban agglomeration in central China, carbon dynamics in the Wuhan City Circle area have been deeply affected by rapid urbanization and climate change in the past two decades. Here, we applied monthly climate data, spatially explicit land use maps, NDVI (Normalized Difference Vegetation Index) images and the CASA (Carnegie–Ames–Stanford Approach) model to estimate the spatial and temporal changes of carbon dynamics in the Wuhan City Circle area from 2000 to 2015. We designed six different scenarios to analyze the effects of climate change and land use change on carbon dynamics. Our simulation of NPP (Net Primary Productivity) increased from 522.63 gC × m−2 to 615.82 gC × m−2 in the Wuhan City Circle area during 2000–2015. Climate change and land use change contributed to total carbon sequestration by −73.3 × 1010 gC and 480 × 1010 gC, respectively. Both precipitation and temperature had a negative effect on carbon sequestration, while radiation had a positive effect. In addition, the positive effect on carbon sequestration from afforestation was almost equal to the negative effect from urbanization between 2000 and 2015. Importantly, these findings highlight the possibility of carrying out both rapid urbanization and ecological restoration simultaneously.

Historic land degradation is an ongoing threat to the Sky Islands of southern Arizona, US, and northern Sonora, Mexico, an area designated as a globally significant biodiversity hotspot. Land degradation has reduced ecosystem services provisioning, released carbon from disturbed soils into the atmosphere, and significantly diminished resilience to climate change. Private land managers in the region have developed methods to reverse degradation and restore biodiversity and ecosystem function. Land managers have used rock detention structures (RDS), technology adapted from traditional Indigenous practices in the region, as a tool for reversing desertification and watershed degradation. The structures were installed primarily for erosion control and water management, but they have had positive impacts on multiple biophysical systems. In this study, we analyze watershed-scale installation of RDS as a nature-based solution for climate change mitigation and adaptation. Case studies include four properties that offer examples of structures that have been in place over a period ranging from 1 to 40 years. We reviewed journal articles and other studies conducted at the four sites, supplemented with interviews, to catalogue the nature-based solutions provided by RDS. This study documents positive impacts on overall stream flow, reduction in peak runoff during inundation events, and increased sedimentation, which increase resilience to drought, erosion, and flooding. Data suggest potential impacts for climate change mitigation, though further research is needed. In addition, results suggest that watershed restoration with RDS offers a host of co-benefits, including an increase in biodiversity and wildlife abundance, an increase in vegetative cover, and increased surface water provisioning over time to support the land-based livelihoods of downstream neighbors. In the discussion, we consider barriers to replication and scalability using the strategy of the UN Decade on Ecosystem Restoration as a guiding framework, discussing issues of awareness, legislation and policy, technical capacity, finance, and gaps in knowledge.

With no single carbon capture and sequestration solution able to limit the global temperature rise to 1.5-2.0 °C by 2100, additional climate stabilization measures are needed to complement current mitigation approaches. Urban farming presents an easy-to-adopt pathway toward carbon neutrality, unlocking extensive urban surface areas that can be leveraged to grow food while sequestering CO2. Urban farming involves extensive surface areas, such as roofs, balconies, and vertical spaces, allowing for soil presence and atmospheric carbon sequestration through air-to-soil contact. In this viewpoint we also advocate the incorporation of enhanced rock weathering (ERW) into urban farming, providing a further opportunity for this recognized negative emissions technology that is gaining momentum worldwide to gain greater utilization.

Boreal forests of Siberia play a relevant role in the global carbon cycle. However, global warming threatens the existence of summergreen larch-dominated ecosystems likely enabling a transition to evergreen tree taxa with deeper active layers. Complex permafrost-vegetation interactions make it uncertain whether these ecosystems could develop into a carbon source rather than continuing atmospheric carbon sequestration under global warming. Consequently, shedding light on the role of current and future active-layer dynamics and the feedbacks with the apparent tree species is crucial to predict boreal forest transition dynamics, and thus for aboveground forest biomass and carbon stock developments. Hence, we established a coupled model version amalgamating a one-dimensional permafrost-multilayer forest land-surface model (CryoGrid), with LAVESI, an individual-based and spatially explicit forest model for larch species (Larix Mill.), extended for this study by including other relevant Siberian forest species and explicit terrain. Following parametrization, we ran simulations with the coupled version to the near future to 2030 with a mild climate-warming scenario. We focus on three regions, covering a gradient of summergreen forests in the east at Spasskaya Pad to mixed summergreen-evergreen forests close to Nyurba, and the warmest area at Lake Khamra in the south-east of Yakutia, Russia. Coupled simulations were run with the newly implemented boreal forest species and compared to runs allowing only one species at a time, as well as to simulations using just LAVESI. Results reveal that the coupled version corrects for overestimation of active-layer thickness (ALT) and soil moisture and large differences in established forests are simulated. We conclude that the coupled version can simulate the complex environment of central Siberia reproducing vegetation patterns making it an excellent tool to disentangle processes driving boreal forest dynamics.

Northern post-glacial lakes are significant, increasing sources of atmospheric carbon through ebullition (bubbling) of microbially-produced methane (CH4) from sediments. Ebullitive CH4 flux correlates strongly with temperature, reflecting that solar radiation drives emissions. However, here we show that the slope of the temperature-CH4 flux relationship differs spatially across two post-glacial lakes in Sweden. We compared these CH4 emission patterns with sediment microbial (metagenomic and amplicon), isotopic, and geochemical data. The temperature-associated increase in CH4 emissions was greater in lake middles—where methanogens were more abundant—than edges, and sediment communities were distinct between edges and middles. Microbial abundances, including those of CH4-cycling microorganisms and syntrophs, were predictive of porewater CH4 concentrations. Results suggest that deeper lake regions, which currently emit less CH4 than shallower edges, could add substantially to CH4 emissions in a warmer Arctic and that CH4 emission predictions may be improved by accounting for spatial variations in sediment microbiota., Arctic lakes are strong and increasing sources of atmospheric methane, but extreme conditions and limited observations hinder robust understanding. Here the authors show that microbes in the middle of Arctic lakes have elevated methane producing potential, and are poised to release even more in the future.

The transformation of the natural landscape into an impervious surface due to urbanization has often been considered an important driver of environmental change, affecting essential urban ecological processes and ecosystem services. Continuous forest degradation and deforestation due to urbanization have led to an increase in atmospheric carbon emissions, risks, and impacts associated with climate change within urban landscapes and beyond them. Hence, urban reforestation has become a reliable long-term alternative for carbon sink and climate change mitigation. However, there is an urgent need for spatially accurate and concise quantification of these forest carbon stocks in order to understand and effectively monitor the accumulation and progress on such ecosystem services. Hence, this study sought to examine the prospect of Sentinel-2 spectral data in quantifying carbon stock in a reforested urban landscape using the random forest ensemble. Results show that Sentinel-2 spectral data estimated reforested forest carbon stock to an RMSE between 0.378 and 0.466 t·ha−1 and R2 of 79.82 and 77.96% using calibration and validation datasets. Based on random forest variable selection and backward elimination approaches, the red-edge normalized difference vegetation index, enhanced vegetation index, modified simple ratio index, and normalized difference vegetation index were the best subset of predictor variables of carbon stock. These findings demonstrate the value and prospects of Sentinel-2 spectral data for predicting carbon stock in reforested urban landscapes. This information is critical for adopting informed management policies and plans for optimizing urban reforested landscapes carbon sequestration capacity and improving their climate change mitigation potential.

Land-use change is an important contributor to atmospheric carbon emissions. Taking Jinhua city in eastern China as an example, this study analyzed the effects on carbon emissions by land-use changes from 2005 to 2018. Then, carbon emissions that will be produced in Jinhua in 2030 were predicted based on the land-use pattern predicted by the CA-Markov model. Finally, a low-carbon optimized land-use pattern more consistent with the law of urban development was proposed based on the prediction and planning model used in this study. The results show that (1) from 2005 to 2018, the area of land used for construction in Jinhua continued to increase, while woodland and cultivated land areas decreased. Carbon emissions from land use rose at a high rate. By 2018, carbon emissions had increased by 1.9 times compared to 2015. (2) During the 2010–2015 period, the total concentration of carbon emissions decreased due to decreases in both the rate of growth in construction land and the rate of decline in a woodland area, as well as an adjustment of the energy structure and the use of polluting fertilizer and pesticide treatments. (3) The carbon emissions produced with an optimal land-use pattern in 2030 are predicted to reduce by 19%. The acreage of woodland in Jinhua’s middle basin occupied by construction land and cultivated land is predicted to reduce. The additional construction land will be concentrated around the main axis of the Jinhua-Yiwu metropolitan area and will exhibit a characteristic ribbon-form with more distinct clusters. The optimized land-use pattern is more conducive to carbon reduction and more in line with the strategy of regional development in the study area. The results of this study can be used as technical support to optimize the land-use spatial pattern and reduce urban land’s contribution to carbon emissions.

Ponderosa pine forests in the southwestern United States of America are overly dense, increasing the risk of high-intensity stand-replacing wildfires that result in the loss of terrestrial carbon and release of carbon dioxide, contributing to global climate change. Restoration is needed to restore forest structure and function so that a more natural regime of higher frequency, lower intensity wildfires returns. However, restoration has been hampered by the significant cost of restoration and other institutional barriers. To create additional revenue streams to pay for restoration, the National Forest Foundation supported the development of a methodology for the estimation and verification of carbon offsets generated by the restoration of ponderosa pine forests in northern Arizona. The methodology was submitted to the American Carbon Registry, a prominent carbon registry, but it was ultimately rejected. This paper presents a post-mortem examination of that methodology and the reasons it was rejected in order to improve the development of similar methodologies in the future. Using a mixed-methods approach, this paper analyzes the potential atmospheric carbon benefits of the proposed carbon offset methodology and the public and peer-reviewed comments from the associated review of the methodology. Results suggest a misalignment between the priorities of carbon registries and the context-specific ecosystem service benefits of this type of restoration, although findings confirm the potential for reductions in released carbon due to restoration, these results illuminate barriers that complicate registering these reductions as voluntary carbon offsets under current guidelines and best practices, especially on public land. These barriers include substantial uncertainty about the magnitude and timing of carbon benefits. Overcoming these barriers will require active reflexivity by the institutions that register voluntary carbon offsets and the institutions that manage public lands in the United States. Such reflexivity, or reconsideration of the concepts and purposes of carbon offsets and/or forest restoration, will allow future approaches to better align objectives for successfully registering restoration-based voluntary carbon offsets. Therefore, the results of this analysis can inform the development of future methodologies, policies, and projects with similar goals in the same or different landscapes.

As climate policy focusing events, wildfires are distinct from hurricanes, floods, and tornados because they also result in the release of massive smoke plumes that contribute to the concentration of atmospheric carbon. However, unlike melting glaciers, wildfires may be easier to dismiss as individual acts of human error, spontaneous acts of mother nature, and/or necessary ecological processes of agricultural renewal. This paper presents a mixed-methods analysis of 150 international and domestic English language newspaper articles related to wildfire events occurring in Australia, Canada, Germany, Greece, Italy, Spain, the United Kingdom, and the United States during the year 2020. The analysis examines how news coverage of wildfire events might focus or diffuse attention to international climate policy and anthropogenic global warming. The quantitative findings provide evidence to suggest that 30% of wildfire coverage is attributed to climate change. However, qualitative analysis suggests that climate change is acknowledged as a blame frame that is often only inferentially attributed to anthropogenic origins. The mixed-methods analysis finds that only 6% of news coverage related wildfire events to emission contributions. The analysis of these exemplar articles suggests that the international travel of wildfire smoke may serve as a focusing event from which to emphasize wildfires as both a consequence of and contributor to, global warming. Findings indicate that environmental coalitions and scientific experts’ engagement with the press are integral to creating frames that link the increasing frequency, duration, and range of wildfire events to climate policy needs.

Tropical and subtropical mangrove swamps, under normal conditions, can sequester large amounts of carbon in their soils but as coastal wetlands, they are prone to hurricane disturbances. This study adds to the understanding of carbon storage capabilities of mangrove wetlands and explores how these capacities might change within the scope of a changing storm climate. In September 2017, Naples Bay, FL, USA (28°5′ N, 81°47′ W) encountered a direct hit from hurricane Irma, a Saffir–Simpson category 3 storm. By comparing carbon storage, forest community structure, and aboveground productivity collected in 2013 and in 2019, we estimated the effects of hurricane Irma on mangrove functions. Aboveground biomass increased during the study period at a rate of approximately 0.72 kg m−2 yr−1, significantly less than the average found in undisturbed mangrove forests. Soil carbon storage decreased at all study sites. On average, 2.7 kg-C m−2 was lost in the top 20 cm between sample collections. Carbon loss in belowground pools could point to a feedback of mangrove swamps on climate change as they lose their ability to store carbon and increase net atmospheric carbon. Nevertheless, mangrove swamps remain resilient to tropical storms in the long term and can recover their carbon storage capacity in the years following a storm.

As the world’s population has tripled (3x) since 1950, with another 50% increase expected by 2100, global annual carbon dioxide emissions growth rate has quadrupled (4x) since 1950 and global energy demand has quintupled (5x), all in the same time period. This discontinuous combination can be called a “3-4-5 Triad” and the sudden acceleration in all three arenas is too stressful on the environment and the damaging effects will be felt globally for centuries to come unless drastic action is taken. More importantly, the energy demand at 5x is outstripping the other two. This clearly means that as the population explodes at 3x, the emerging middle class wants almost twice as much as their usual share as fossil-fueled generators spread around the globe and modern conveniences become more and more desirable. However, such energy demand at 5x is an artificial human need that is predicted by RMI.org to result in four to five billion new window-mounted air conditioners by 2050 that will add even more to the global warming caused by increasing atmospheric carbon. By an examination of paleoclimatology for the past 420,000 years, it is demonstrable that reducing the concentration of this single most prolific heat-trapping gas by geoengineering back to pre-industrial levels of less than 300 ppm can actually give humankind a collective control over the world’s rapidly rising average global temperature and once more, a temperate climate to live in.

Global climate change is expected with ever rising human population on the planet earth. The different anthropogenic activities have resulted in increased levels of greenhouse gases(GHSs) in the atmosphere, higher temperatures, aberrant precipitation patterns and several other climate change that would affect all lives on this planet. This review article addresses the adaptation and mitigation of climate change through assessment of carbon capture, storage and utilization by fruit crops. Most recently, there is an increasing attention on the carbon cycles of terrestrial ecosystems because biosphere roughly fixes 7 to12 percent of emissions caused by human activities. Perennial plants like Forests, fruit Orchards and grasslands are efficient sinks agent of atmospheric Carbon, whereas field crops are great source of GHGs due to soil disturbance, emission of methane or nitrous oxide from burning straw, and field management involving direct (fuel) or indirect (chemicals) emissions from fossil fuels. Thus, there is a need to establish a novel agricultural systems which can minimize the emissions of harmful gases and is capable of sequestering carbon within the atmosphere. Fruit orchards and vineyards have great structural characteristics like long life cycle; permanent organs such as trunk, branches, and roots; null soil tillage (preserves soil organic matter), high quality and yield which allows them to accumulate more Carbon. Hence, the fruit plants have significant potential to sequester carbon in atmosphere. However, the efficiency of carbon sequestration by different fruit crops and their management systems may vary due to their growth and development patterns, physiological behaviour, biomass accumulation, and environmental factors.

Circular economy concepts—including a circular bioeconomy—aim to transition the current, essentially linear, economic system to a more sustainable one. However, organizations and researchers currently define the circular economy concept differently, resulting in inconsistencies and difficulty in effectively implementing the framework. In this paper, we provide our perspective on the conceptual definitions of the circular economy, bioeconomy, and circular bioeconomy, outlining potential overlaps and differences and proposing a harmonized interpretation that stresses the importance of the carbon cycle. We conclude that the key goal of a circular economy is to slow, narrow, and close material resource loops, built on the foundation of renewable energy and non-toxic materials. Further, a sustainable bioeconomy goes beyond simply switching fossil resources with renewable, biological resources. It requires low-carbon energy inputs, sustainable supply chains, and promising disruptive conversion technologies for the sustainable transformation of renewable bioresources to high-value bio-based products, materials, and fuels. The bio-based circular carbon economy, in particular, stresses capturing atmospheric carbon via photosynthesis and exploiting this unique feature to the fullest extent possible. It sits at the intersection between the circular economy and the bioeconomy concept, resulting in a framework that focuses on closing the carbon cycle and stressing the opportunity to create an additional carbon sink capability in the technosphere by utilizing biogenic carbon for products and materials that are circulated in same or improved use cycles. Lastly, a sustainable circular bioeconomy transition will necessitate a set of consistent metrics that fit all products and industries.

International audience; Better understanding the fate of the atmospheric carbon (C) captured by plant photosynthesis is essential to improve natural C flux modelling. Soils are considered as the major terrestrial bioreactor and repository of plant C, whereas channel networks of floodplain rivers collect and transport, throughout the aquatic continuum, a significant part of plant primary production until its export through outgassing or sequestration in marine sediments. Here, we show that river meandering in forested floodplains is a crucial and widely overlooked Earth surface process promoting C fluxes from the atmosphere to the aquatic continuum, via the floodplain vegetation. Over a recent period of 35 years (1984–2019), we quantified those C fluxes in one of the most active meandering rivers on Earth, the Ucayali River, Peru, South America. We used map time series combined with above-ground forest C data to derive the amount of C that is annually captured by the growing floodplain vegetation within the active meander belt, as well as exported to the aquatic continuum by lateral channel erosion. We found that the annual building and erosion of forested floodplain areas was nearly balanced over time with 19.0±7.7×103 ha−1 yr−1 and 19.8±6.7×103 ha−1 yr−1, respectively. While growing forests within the active meander belt annually captured 0.01±0.05×106 Mg C yr−1, lateral channel erosion provided the nearly 100-fold amount of C to the river channel and its streamflow, i.e. 0.9±0.4×106 Mg C yr−1. Our findings revealed that the migration of the Ucayali River channel provided nearly 10-times more lignified C per unit area to the aquatic continuum (44.7±21.4 Mg C ha−1 yr−1) than non-meandering central Amazonian floodplains do. Together, these findings point to the importance of quantifying the overall contribution of meandering rivers to natural C fluxes worldwide.

The ACT‐America project is a NASA Earth Venture Suborbital‐2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT‐America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower‐based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016–2019 over three regions of the US (Mid‐Atlantic, Midwest and South) using two NASA research aircraft (B‐200 and C‐130). We performed three flight patterns (fair weather, frontal crossings, and OCO‐2 underflights) and collected more than 1,140 h of airborne measurements via level‐leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT‐America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT‐America data sets., Key Points Atmospheric Carbon and Transport – America (ACT‐America) provides a unique, weather‐oriented collection of atmospheric CO2, CH4, trace gases, and meteorological properties measurementsACT‐America data are free and open to the public from the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC)ACT‐America data are uniquely suited to improve the accuracy and precision of regional inverse greenhouse gas (GHG) flux estimates