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1.
J Environ Manage ; 301: 113882, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34638040

RESUMO

Due to its increasing demands for fossil fuels, Indonesia needs an alternative energy to diversify its energy supply. Landfill gas (LFG), which key component is methane (CH4), has become one of the most attractive options to sustain its continued economic development. This exploratory study seeks to demonstrate the added value of landfilled municipal solid waste (MSW) in generating sustainable energy, resulting from CH4 emissions in the Bantargebang landfill (Jakarta). The power generation capacity of a waste-to-energy (WTE) plant based on a mathematical modeling was investigated. This article critically evaluated the production of electricity and potential income from its sale in the market. The project's environmental impact assessment and its socio-economic and environmental benefits in terms of quantitative and qualitative aspects were discussed. It was found that the emitted CH4 from the landfill could be reduced by 25,000 Mt annually, while its electricity generation could reach one million kW â‹…h annually, savings on equivalent electricity charge worth US$ 112 million/year (based on US' 8/kW ⋅ h). An equivalent CO2 mitigation of 3.4 × 106 Mt/year was obtained. The income from its power sale were US$ 1.2 ×106 in the 1st year and 7.7 ×107US$ in the 15th year, respectively, based on the projected CH4 and power generation. The modeling study on the Bantargebang landfill using the LFG extraction data indicated that the LFG production ranged from 0.05 to 0.40 m3 per kg of the landfilled MSW. The LFG could generate electricity as low as US' 8 per kW ⋅ h. With respect to the implications of this study, the revenue not only defrays the cost of landfill's operations and maintenance (O&M), but also provides an incentive and means to further improve its design and operations. Overall, this work not only leads to a diversification of primary energy, but also improves environmental protection and the living standard of the people surrounding the plant.


Assuntos
Gases de Efeito Estufa , Eliminação de Resíduos , Eletricidade , Humanos , Indonésia , Metano/análise , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
2.
Sci Total Environ ; 803: 150008, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34482130

RESUMO

The intensifying globalization contributes to the anthropogenic methane (CH4) emissions outsourcing, a strong greenhouse gas and harmful air pollutant, through the increasingly complex global trade network. However, the CH4 flow patterns embodied in global traded goods and services have not been interpreted from the perspective of a complex network. In this paper, we integrate global CH4 emission inventory from the EDGAR (the Emission Database for Global Atmospheric Research) databases, global multi-regional input-output model from the GTAP database, and complex network analysis to reveal the structural characteristics of the global CH4 flow network (GCFN). In the GCFN, more than one quarter of the global anthropogenic CH4 emissions in 2014 are associated with international trade. The top 20 economies contribute to about 70% of the total embodied CH4 emission flows. The GCFNs mainly consist of tripartite patterns centered on China, the USA and Russia. Some emerging countries, such as Thailand and Brazil, also exhibit dominated positions in different kinds of GCFNs. Moreover, the core-periphery structure of the GCFN confirms the existence of a few hub economies associated with a large amount of CH4 emissions. The results emphasize the multinational cooperation on global CH4 emission mitigation, and well-focused mitigation policies should be implemented on some key economies.


Assuntos
Gases de Efeito Estufa , Serviços Terceirizados , Comércio , Internacionalidade , Metano/análise
3.
Sci Total Environ ; 803: 149577, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487896

RESUMO

Forested coastal wetlands are globally important systems sequestering carbon and intercepting nitrogen pollution from nutrient-rich river systems. Coastal wetlands that have suffered extensive disturbance are the target of comprehensive restoration efforts. Accurate assessment of restoration success requires detailed mechanistic understanding of wetland soil biogeochemical functioning across restoration chrono-sequences, which remains poorly understood for these sparsely investigated systems. This study investigated denitrification and greenhouse gas fluxes in mangrove and Melaleuca forest soils of Vietnam, using the 15N-Gas flux method. Denitrification-derived N2O was significantly higher from Melaleuca than mangrove forest soils, despite higher potential rates of total denitrification in the mangrove forest soils (8.1 ng N g-1 h-1) than the Melaleuca soils (6.8 ng N g-1 h-1). Potential N2O and CO2 emissions were significantly higher from the Melaleuca soils than from the mangrove soils. Disturbance and subsequent recovery had no significant effect on N biogeochemistry except with respect to the denitrification product ratio in the mangrove sites, which was highest from the youngest mangrove site. Potential CO2 and CH4 fluxes were significantly affected by restoration in the mangrove soils. The lowest potential CO2 emissions were observed in the mid-age plantation and potential CH4 fluxes decreased in the older forests. The mangrove system, therefore, may remove excess N and improve water quality with low greenhouse gas emissions, whereas in Melaleucas, increased N2O and CO2 emissions also occur. These emissions are likely balanced by higher carbon stocks observed in the Melaleuca soils. These mechanistic insights highlight the importance of ecosystem restoration for pollution attenuation and reduction of greenhouse gas emissions from coastal wetlands. Restoration efforts should continue to focus on increasing wetland area and function, which will benefit local communities with improved water quality and potential for income generation under future carbon trading.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Desnitrificação , Ecossistema , Monitoramento Ambiental , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Solo , Áreas Alagadas
4.
Chemosphere ; 286(Pt 2): 131663, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34371357

RESUMO

In this study, an immobilization method for forming and keeping dominant petroleum degradation bacteria was successfully developed by immobilizing Pseudomonas, Acinetobacter, and Sphingobacterium genus bacteria on wheat bran biochar pyrolyzed at 300, 500, and 700 °C. The removal efficiency indicated that the highest TPHs (total petroleum hydrocarbons) removal rate of BC500-4 B (biochar pyrolyzed at 500 °C with four kinds of petroleum bacteria) was 58.31%, which was higher than that of BC500 (36.91%) and 4 B (43.98%) used alone. The soil properties revealed that the application of biochar increased the content of organic matter, available phosphorus, and available potassium, but decreased pH and ammonium nitrogen content in soil. Bacterial community analysis suggested that the formation of dominant degrading community represented by Acinetobacter played key roles in TPHs removal. The removal rate of alkanes was similar to that of TPHs. Besides, biochar and immobilized material can also mediate greenhouse gas emission while removing petroleum, biochar used alone and immobilized all could improve CO2 emission, but decrease N2O emission and had no significant impact on CH4 emission. Furthermore, it was the first time to found the addition of Acinetobacter genus bacteria can accelerate the process of forming a dominant degrading community in wheat bran biochar consortium. This study focused on controlling greenhouse gas emission which provides a wider application of combining biochar and bacteria in petroleum soil remediation.


Assuntos
Gases de Efeito Estufa , Petróleo , Poluentes do Solo , Álcalis , Bactérias , Biodegradação Ambiental , Carvão Vegetal , Fibras na Dieta , Gases de Efeito Estufa/análise , Hidrocarbonetos , Petróleo/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise
5.
Sci Total Environ ; 803: 149935, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487900

RESUMO

Excreta deposition onto pasture, range and paddocks (PRP) by grazing ruminant constitute a source of nitrous oxide (N2O), a potent greenhouse gas (GHG). These emissions must be reported in national GHG inventories, and their estimation is based on the application of an emission factor, EF3PRP (proportion of nitrogen (N) deposited to the soil through ruminant excreta, which is emitted as N2O). Depending on local data available, countries use various EF3PRPs and approaches to estimate N2O emissions from grazing ruminant excreta. Based on ten case study countries, this review aims to highlight the uncertainties around the methods used to account for these emissions in their national GHG inventories, and to discuss the efforts undertaken for considering factors of variation in the calculation of emissions. Without any local experimental data, 2006 the IPCC default (Tier 1) EF3PRPs are still widely applied although the default values were revised in 2019. Some countries have developed country-specific (Tier 2) EF3PRP based on local field studies. The accuracy of estimation can be improved through the disaggregation of EF3PRP or the application of models; two approaches including factors of variation. While a disaggregation of EF3PRP by excreta type is already well adopted, a disaggregation by other factors such as season of excreta deposition is more difficult to implement. Empirical models are a potential method of considering factors of variation in the establishment of EF3PRP. Disaggregation and modelling requires availability of sufficient experimental and activity data, hence why only few countries have currently adopted such approaches. Replication of field studies under various conditions, combined with meta-analysis of experimental data, can help in the exploration of influencing factors, as long as appropriate metadata is recorded. Overall, despite standard IPCC methodologies for calculating GHG emissions, large uncertainties and differences between individual countries' accounting remain to be addressed.


Assuntos
Gases de Efeito Estufa , Animais , Gases de Efeito Estufa/análise , Óxido Nitroso/análise , Ruminantes , Estações do Ano , Solo
6.
Sci Total Environ ; 804: 150225, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798746

RESUMO

Forest thinning is a major forest management practice worldwide and may lead to profound alterations in the fluxes of soil greenhouse gases (GHGs). However, the global patterns and underlying mechanisms of soil GHG fluxes in response to forest thinning remain poorly understood. Here, we conducted a global meta-analysis of 106 studies to assess the effects of forest thinning on soil GHG fluxes and the underpinning mechanisms. The results showed that forest thinning significantly increased soil CO2 emission (mean lnRR: 0.07, 95% CI: 0.03-0.11), N2O emission (mean lnRR: 0.39, 95% CI: 0.16-0.61) and decreased CH4 uptake (mean Hedges' d: 0.98, 95% CI: 0.32-1.64). Furthermore, the negative response of soil CH4 uptake was amplified by thinning intensity, and the positive response of soil N2O emission decreased with recovery time after thinning. The response of soil CO2 emission was mainly correlated with changes in fine root biomass and soil nitrogen content, and the response of soil CH4 uptake was related to the changes in soil moisture and litterfall. Moreover, the response of soil N2O emission was associated with changes in soil temperature and soil nitrate nitrogen content. Thinning also increased the total balance of the three greenhouse gas fluxes in combination, which decreased with recovery time. Our findings highlight that thinning significantly increases soil GHG emissions, which is crucial to understanding and predicting ecosystem-climate feedbacks in managed forests.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Ecossistema , Florestas , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise , Solo
7.
Sci Total Environ ; 802: 149685, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464805

RESUMO

Small, shallow waterbodies are potentially important sites of greenhouse gas release to the atmosphere. The role of ebullition may be enhanced here relative to larger and deeper systems, due to their shallow water, but these features remain relatively infrequently studied in comparison to larger systems. Herein, we quantify ebullitive release of methane (CH4) in small shallow ponds in three regions of North America and investigate the role of potential drivers. Shallow ponds exhibited open-water season ebullitive CH4 release rates as high as 40 mmol m-2 d-1, higher than previously reported for similar systems. Ebullitive release of CH4 varied by four orders of magnitude across our 15 study sites, with differences in flux rates both within and between regions. What is less clear are the drivers responsible for these differences. There were few relationships between open water-season ebullitive flux and physicochemical characteristics, including organic matter, temperature, and sulphate. Temperature was only weakly related to ebullitive CH4 release across the study when considering all observation intervals. Only four individual sites exhibited significant relationships between temperature and ebullitive CH4 release. Other sites were unresponsive to temperature, and region-specific factors may play a role. There is some evidence that where surface water sulphate concentrations are high, CH4 production and release may be suppressed. Missouri sites (n = 5) had characteristically low ebullitive CH4 release; here bioturbation could be important. While this work greatly expands the number of open-water season ebullition rates for small and shallow ponds, more research is needed to disentangle the role of different drivers. Further investigation of the potential thresholding behaviour of sulphate as a control on ebullitive CH4 release in lentic systems is one such opportunity. What is clear, however, is that efforts to scale emissions (e.g., as a function of temperature) must be undertaken with caution.


Assuntos
Gases de Efeito Estufa , Metano , Atmosfera , Metano/análise , Lagoas , Temperatura
8.
J Environ Manage ; 301: 113934, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34731952

RESUMO

As China urbanized and its economy grew rapidly, its food production and consumption patterns changed dramatically over the past three decades. With this in mind, we evaluate how the nation's greenhouse gas (GHG) emissions related to food production and consumption altered from 1987 to 2017. We further explore key factors that affect GHG emission changes from agricultural production and household diet perspectives. We find that the GHG emissions from China's food production rose 51 percent, while that from food consumption rose 64 percent. The rise in GHG footprint of China's food production was largely caused by the increasing material- and energy-intensive food production system. Agricultural modernization was a main cause of the rise in GHGs, as China was late to the game in improving agricultural productivity. But a more meat-intensive diet accompanied by a general rise in households' use of processed food also helped to drive these transformations. China's growing appetite for meat not only intensified GHG mitigation pressures domestically, but also abroad, as Chinese households began to demand greater variety that was satisfied via imports. Indeed, GHG emissions embodied in imported meats rose over eleven-fold from 2007 to 2017. Through this study, we highlight the importance of future policy-making focused on a more sustainable food system in China to benefit the world's environment, health, and climate.


Assuntos
Gases de Efeito Estufa , Agricultura , China , Efeito Estufa , Gases de Efeito Estufa/análise , Carne
9.
Proc Natl Acad Sci U S A ; 118(46)2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34753820

RESUMO

The COVID-19 global pandemic and associated government lockdowns dramatically altered human activity, providing a window into how changes in individual behavior, enacted en masse, impact atmospheric composition. The resulting reductions in anthropogenic activity represent an unprecedented event that yields a glimpse into a future where emissions to the atmosphere are reduced. Furthermore, the abrupt reduction in emissions during the lockdown periods led to clearly observable changes in atmospheric composition, which provide direct insight into feedbacks between the Earth system and human activity. While air pollutants and greenhouse gases share many common anthropogenic sources, there is a sharp difference in the response of their atmospheric concentrations to COVID-19 emissions changes, due in large part to their different lifetimes. Here, we discuss several key takeaways from modeling and observational studies. First, despite dramatic declines in mobility and associated vehicular emissions, the atmospheric growth rates of greenhouse gases were not slowed, in part due to decreased ocean uptake of CO2 and a likely increase in CH4 lifetime from reduced NO x emissions. Second, the response of O3 to decreased NO x emissions showed significant spatial and temporal variability, due to differing chemical regimes around the world. Finally, the overall response of atmospheric composition to emissions changes is heavily modulated by factors including carbon-cycle feedbacks to CH4 and CO2, background pollutant levels, the timing and location of emissions changes, and climate feedbacks on air quality, such as wildfires and the ozone climate penalty.


Assuntos
Poluição do Ar , Atmosfera/química , COVID-19/psicologia , Gases de Efeito Estufa , Modelos Teóricos , COVID-19/epidemiologia , Dióxido de Carbono , Mudança Climática , Humanos , Metano , Óxidos de Nitrogênio , Ozônio
10.
J Environ Manage ; 300: 113836, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34649322

RESUMO

Trade has been substantially influencing regional economic development, environmental sustainability, and human well-being. Enabled by the decomposition analysis, pollution haven hypothesis or "no-trade" scenarios (NTSs), the effects of trade on global/national social-economic-environmental development have been revealed. However, major limitations (e.g., using with-trade economic structures or neglecting price differences) existed in previous studies, and thus made the previous assessments of trade's effects unsatisfactorily. This study develops a novel NTS that addresses the existing limitations, and further applies it to estimate the effect of trade on global economic development and greenhouse gas (GHG) emissions. We show that current international trade benefits the global economic growth but with a consequence of more GHG emissions compared with the NTS. The hypothetical production in small countries (e.g., Luxembourg or Japan) would be more constrained by the production factors (e.g., land) under the NTS, compared with those factor-endowment countries (e.g., the United States or India). For country-specific analysis, we find that today's developed countries would have a substantial increase in their GHG emissions of clothing- and service-related products under the NTS, whereas countries with net-export (e.g., China or Brazil) would have less GHG emissions under the NTS. Enhancing future global collaborations is vital, especially for small or resource-deficient economies, if they are to achieve the Sustainable Development Goals.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Comércio , Desenvolvimento Econômico , Efeito Estufa , Humanos , Internacionalidade
11.
Artigo em Inglês | MEDLINE | ID: mdl-34682714

RESUMO

The construction industry has a considerable environmental impact in societies, which must be controlled to achieve adequate sustainability levels. In particular, cement production contributes 5-8% of CO2 emissions worldwide, mainly from the utilization of clinker. This study applied Life Cycle Assessment (LCA) methodology to investigate the environmental impact of cement production and explore environmental improvements obtained by adding marble waste sludges in the manufacture of Portland cement. It was considered that 6-35% of the limestone required for its production could be supplied by marble waste sludge (mainly calcite), meeting the EN 197-1:2011 norm. Energy consumption and greenhouse gas (GHG) emission data were obtained from the Ecovent database using commercial LCA software. All life cycle impact assessment indicators were lower for the proposed "eco-cement" than for conventional cement, attributable to changes in the utilization of limestone and clinker. The most favorable results were achieved when marble waste sludge completely replaced limestone and was added to clinker at 35%. In comparison to conventional Portland cement production, this process reduced GHG emissions by 34%, the use of turbine waters by 60%, and the emission of particles into the atmosphere by 50%. Application of LCA methodology allowed evaluation of the environmental impact and improvements obtained with the production of a type of functional eco-cement. This approach is indispensable for evaluating the environmental benefits of using marble waste sludges in the production of cement.


Assuntos
Gases de Efeito Estufa , Esgotos , Animais , Carbonato de Cálcio , Materiais de Construção , Efeito Estufa , Estágios do Ciclo de Vida
14.
Ying Yong Sheng Tai Xue Bao ; 32(8): 2666-2674, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34664438

RESUMO

Cover crops are grown in temporal and spatial gaps of agricultural production to reduce or avoid soil exposure. As it can protect farmland soil from wind erosion, water erosion and human disturbance, planting cover crops is considered as a new type of conservation tillage practice. Here, we briefly introduced the planting management of cover crops, including crop species, planting modes, and the returning to farmland after their termination, which could provide a reference for efficiently planting cover crops at large scale during the fallow period. Based on domestic and foreign studies, we summarized the benefits of cover crops on agroecosystem, including cash crops, soil quality, weed control, greenhouse gas emission, and soil microbes. Our review illustrated their importance in improving soil quality and achieving sustainable agricultural development, despite the limitation of cover crops, including unobvious benefits in the short-term and the reduction of crop yield caused by improper management.


Assuntos
Gases de Efeito Estufa , Solo , Agricultura , Produtos Agrícolas , Humanos
15.
Environ Sci Technol ; 55(20): 14225-14233, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34614357

RESUMO

After centuries of decline, oyster populations are now on the rise in coastal systems globally following aquaculture development and restoration efforts. Oysters regulate the biogeochemistry of coastal systems in part by promoting sediment nutrient recycling and removing excess nitrogen via denitrification. Less clear is how oysters alter sediment greenhouse gas (GHG) fluxes-an important consideration as oyster populations grow. Here, we show that sediments in oyster habitats produce carbon dioxide (CO2), with highest rates in spring (2396.91 ± 381.98 µmol CO2 m-2 h-1) following deposition of seasonal diatom blooms and in summer (2795.20 ± 307.55 µmol CO2 m-2 h-1) when temperatures are high. Sediments in oyster habitats also consistently released methane to the water column (725.94 ± 150.34 nmol CH4 m-2 h-1) with no seasonal pattern. Generally, oyster habitat sediments were a sink for nitrous oxide (N2O; -36.11 ± 7.24 nmol N2O m-2 h-1), only occasionally releasing N2O in spring. N2O release corresponded to high organic matter and dissolved nitrogen availability, suggesting denitrification as the production pathway. Despite potential CO2 production increases under aquaculture in some locations, we conclude that in temperate regions oysters have an overall negligible impact on sediment GHG cycling.


Assuntos
Gases de Efeito Estufa , Ostreidae , Animais , Dióxido de Carbono/análise , Ecossistema , Monitoramento Ambiental , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise
16.
Artigo em Inglês | MEDLINE | ID: mdl-34639670

RESUMO

Oxygen production in cryogenic air separation units is related to a significant carbon footprint and its supply in the medicinal sphere became critical during the recent COVID-19 crisis. An improved unit design was proposed, utilizing a part of waste heat produced during air pre-cooling and intercooling via absorption coolers, to reduce power consumption. Variable ambient air humidity impact on compressed air dryers' regeneration was also considered. A steady-state process simulation of a model 500 t h-1 inlet cryogenic air separation unit was performed in Aspen Plus® V11. Comparison of a model without and with absorption coolers yielded an achievable reduction in power consumption for air compression and air dryer regeneration by 6 to 9% (23 to 33 GWh year-1) and a favorable simple payback period of 4 to 10 years, both depending on air pressure loss in additional heat exchangers to be installed. The resulting specific oxygen production decrease amounted to EUR 2-4.2 t-1. Emissions of major gaseous pollutants from power production were both calculated by an in-house developed thermal power plant model and adopted from literature. A power consumption cut was translated into the following annual greenhouse gas emission reduction: CO2 16 to 30 kilotons, CO 0.3 to 2.3 tons, SOx 4.7 to 187 tons and NOx 11 to 56 tons, depending on applied fossil fuel-based emission factors. Considering a more renewable energy sources-containing energy mix, annual greenhouse gas emissions decreased by 50 to over 80%, varying for individual pollutants.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , COVID-19 , Gases de Efeito Estufa , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Efeito Estufa , Temperatura Alta , Humanos , Oxigênio , SARS-CoV-2
17.
PLoS Comput Biol ; 17(10): e1009321, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34662331

RESUMO

In 2020, the world faced the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic that drastically altered people's lives. Since then, many countries have been forced to suspend public gatherings, leading to many conference cancellations, postponements, or reorganizations. Switching from a face-to-face to a remote conference became inevitable and the ultimate solution to sustain scientific exchanges at the national and the international levels. The same year, as a committee, we were in charge of organizing the major French annual conference that covers all computational biology areas: The "Journées Ouvertes en Biologie, Informatique et Mathématiques" (JOBIM). Despite the health crisis, we succeeded in changing the conference format from face to face to remote in a very short amount of time. Here, we propose 10 simple rules based on this experience to modify a conference format in an optimized and cost-effective way. In addition to the suggested rules, we decided to emphasize an unexpected benefit of this situation: a significant reduction in greenhouse gas (GHG) emissions related to travel for scientific conference attendance. We believe that even once the SARS-CoV-2 crisis is over, we collectively will have an opportunity to think about the way we approach such scientific events over the longer term.


Assuntos
COVID-19 , Biologia Computacional , Congressos como Assunto , Pandemias , SARS-CoV-2 , Comunicação por Videoconferência , COVID-19/epidemiologia , COVID-19/transmissão , Biologia Computacional/organização & administração , Estudos de Viabilidade , França , Gases de Efeito Estufa/análise , Humanos , Relações Interpessoais , Teletrabalho , Viagem
18.
Environ Sci Technol ; 55(21): 14795-14805, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34637286

RESUMO

Stabilizing the global climate within safe bounds will require greenhouse gas (GHG) emissions to reach net zero within a few decades. Achieving this is expected to require removal of CO2 from the atmosphere to offset some hard-to-eliminate emissions. There is, therefore, a clear need for GHG accounting protocols that quantify the mitigation impact of CO2 removal practices, such as biochar sequestration, that have the potential to be deployed at scale. Here, we have developed a GHG accounting methodology for biochar application to mineral soils using simple parameterizations and readily accessible activity data that can be applied at a range of scales including farm, supply chain, national, or global. The method is grounded in a comprehensive analysis of current empirical data, making it a robust method that can be used for many applications including national inventories and voluntary and compliance carbon markets, among others. We show that the carbon content of biochar varies with feedstock and production conditions from as low as 7% (gasification of biosolids) to 79% (pyrolysis of wood at above 600 °C). Of this initial carbon, 63-82% will remain unmineralized in soil after 100 years at the global mean annual cropland-temperature of 14.9 °C. With this method, researchers and managers can address the long-term sequestration of C through biochar that is blended with soils through assessments such as GHG inventories and life cycle analyses.


Assuntos
Gases de Efeito Estufa , Agricultura , Dióxido de Carbono/análise , Carvão Vegetal , Gases de Efeito Estufa/análise , Óxido Nitroso/análise , Solo
19.
Environ Sci Technol ; 55(21): 14806-14816, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34652143

RESUMO

This study presents a cradle-to-grave life cycle analysis (LCA) of the greenhouse gas (GHG) emissions of the electricity generated from forest biomass in different regions of the United States (U.S.), taking into consideration regional variations in biomass availabilities and logistics. The regional biomass supply for a 20 MW bioelectricity facility is estimated using the Land Use and Resource Allocation (LURA) model. Results from LURA and data on regional forest management, harvesting, and processing are incorporated into the GHGs, Regulated Emissions, and Energy Use in Technologies (GREET) model for LCA. The results suggest that GHG emissions of mill residues-based pathways can be 15-52% lower than those of pulpwood-based pathways, with logging residues falling in between. Nonetheless, our analysis suggests that screening bioenergy projects on specific feedstock types alone is not sufficient because GHG emissions of a pulpwood-based pathway in one state can be lower than those of a mill residue-based pathway in another state. Furthermore, the available biomass supply often consists of several woody feedstocks, and its composition is region-dependent. Forest biomass-derived electricity is associated with 86-93% lower life-cycle GHG emissions than the emissions of the average grid electricity in the U.S. Key factors driving bioelectricity GHG emissions include electricity generation efficiency, transportation distance, and energy use for biomass harvesting and processing.


Assuntos
Poluentes Atmosféricos , Gases de Efeito Estufa , Poluentes Atmosféricos/análise , Animais , Biomassa , Eletricidade , Florestas , Efeito Estufa , Estágios do Ciclo de Vida , Estados Unidos
20.
Environ Sci Technol ; 55(21): 14546-14555, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34677952

RESUMO

Croplands are the largest anthropogenic source of nitrous oxide (N2O), a powerful greenhouse gas that contributes to the growing atmospheric N2O burden. However, few studies provide a comprehensive depiction of future cropland-N2O emissions on a national scale due to a lack of accurate cropland prediction data. Herein, we present a newly developed distributed land-use change prediction model for the high-precision prediction of national-scale land-use change. The high-precision land-use data provide an opportunity to elucidate how the changes in cropland area will affect the magnitude and spatial distribution of N2O emissions from China's croplands during 2020-2070. The results showed a declining trend in China's total cropland-N2O emissions from 0.44 ± 0.03 Tg N/year in 2020 to 0.39 ± 0.07 Tg N/year in 2070, consistent with a cropland area reduction from (1.78 ± 0.02) × 108 ha to (1.40 ± 0.15) × 108 ha. However, approximately 31% of all calculated cities in China would emit more than the present level. Furthermore, different land use and climate change scenarios would have important impacts on cropland-N2O emissions. The Grain for Green Plan implemented in China would effectively control emissions by approximately 12%.


Assuntos
Agricultura , Gases de Efeito Estufa , China , Produtos Agrícolas , Gases de Efeito Estufa/análise , Óxido Nitroso/análise , Solo
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