Cumulative Emissions Reduction Research Articles

Exploring Synergistic GHG Emissions Mitigation Potential and Costs of Room Air Conditioners.

This study explores the potential of synergistically reducing direct (refrigerant) and indirect (electricity) greenhouse gas (GHG) emissions in the global room air conditioning (RAC) sector, based on 80% of global RAC manufactured in China. Three scenarios are evaluated: Business-as-usual (BAU) based on maintaining refrigerant and energy efficiency levels from 2021 China RAC sales shares, Kigali Amendment compliant with 10% energy efficiency improvement by 2025 (KAE), and accelerated refrigerant transition and energy efficiency improvement (ATE). Each scenario considers the costs of refrigerant and efficiency measures for export market groups based on Kigali Amendment classifications. BAU predicts around 1 Gt CO2-eq average annual global RAC emissions (2022-2060). Cumulative emission reductions in China's RAC manufacturing under KAE and ATE are 12.2 and 17.2 Gt CO2-eq A5II and A5I (except China), presenting cost-effective abatement measures, with average costs of -$51.4 and -$68.8/t CO2-eq in KAE and ATE. Cumulative average abatement costs are around $18 and $4/t CO2-eq globally. KAE and ATE scenarios would avoid surface temperature rises of 0.023 (±0.002) °C and 0.027 (±0.003) °C, respectively, versus BAU. Collaboration between China and importing countries is urged to enhance energy efficiency in RACs traded, ensuring sustainable mitigation aligned with the Kigali Amendment.

Influence of Chinese herbal plants on greenhouse gas emissions from pig manure composting and fermentation

To reduce greenhouse gas emissions during the composting of animal manure and promote the resource utilization of Chinese herbal plants, experiments on pig manure composting were conducted in a plastic greenhouse. A mixture of herbal powders (Radix isatidis and Radix Polygoni Multiflori, mixed in a 1:1 ratio) was added to the pig manure at concentrations of 0.05%, 0.1%, and 0.5% (w/w), respectively. The results showed that the emission peaks of greenhouse gases occurred in the early stages of composting. The addition of 0.5% of a mixture of Chinese herbal plant powders resulted in a significant reduction in cumulative emissions of CO2 (45.0%) and N2O (60.0%) compared to the control. This treatment also resulted in the lowest global warming potential, measured at 91.3 g kg−1, and significantly increased the germination index. The study concluded that adding 0.5% Chinese herbal plant powder to compost effectively mitigated greenhouse gas emissions during the composting process.

Towards Sustainable Mobility: Assessing the Benefits and Implications of Internal Combustion Engine Vehicle Bans and Battery Electric Vehicle Uptake in Qatar

The global shift towards sustainable transportation, primarily through vehicle electrification, is critical in addressing climate change. Qatar presents a knowledge gap with specific challenges and opportunities in this transition. This study calculates the potential reduction in CO2-eq, NOx, and PM2.5 emissions resulting from substituting Internal Combustion Engine Vehicles (ICEVs) with Battery Electric Vehicles (BEVs) in Qatar, considering ICEV ban scenarios in 2030, 2035, and 2040, alongside five policy pathways. A Vehicle Stock Model (VSM) simulates Qatar’s fleet evolution from 2022 to 2050, focusing on the vehicle’s operational phase. An ICEV ban in 2030 would result in a 34% cumulative emission reduction in road transport between 2022 and 2050 compared with the Business-as-Usual (BAU) scenario. For NOx and PM2.5, cumulative emissions for the 2030 ICEV ban pathways are approximately 20% and 9% lower, respectively, compared with BAU. This study underscores the necessity of localising environmental strategies to meet Qatar’s specific needs and climate commitments, where results indicate significant emission reductions are possible through BEVs.

The synergistic decarbonization potential from construction industry and upstream sectors with a city-scale: A case study of hangzhou, China

How to reduce Carbon Emissions from the Construction Industry (CECI) is one of the key issues in China's efforts to achieve its “dual-carbon target”. The Carbon Emission of the building Materialization Process (CEMP) is the main source of CECI, originating from both the upstream sector and the construction industry itself. Researching the synergistic decarbonization potential and reduction pathways of the construction industry and upstream sectors can help guide sustainable development. Focusing on the city scale, this study establishes a bottom-up framework based on system dynamics and carbon intensity methods to explore the possibilities of CEMP. The framework comprises a dynamic material flow analysis module and a carbon emission accounting module. The Logarithmic Mean Divisia Index (LMDI) method is employed to elucidate the emission reduction potentials of various factors. The results show that in the case of Hangzhou: (1) Without control measures, CEMP will reach a maximum of 25.1 million tons, and a substantial scale of 14.9 million tons remaining in 2060. (2) Through synergistic decarbonization, the cumulative emission reduction over the next 40 years could reach 323.4 million tons, and by 2060, CEMP could decrease to 3.7 million tons of CO2. Achieving carbon neutrality in the construction industry still requires carbon offsets from other sectors. (3) The decarbonization potential mainly comes from controlling the new construction area and carbon emission reduction in material production process, contributing 45.4% and 36.9%, respectively. This study reveals the significant pressure faced by the construction industry in achieving carbon neutrality. It also underscores that further controlling material demand and reducing the carbon intensity of materials is a prerequisite for Hangzhou's construction industry to achieve carbon neutrality.

Effects of Long-Term Controlled-Release Urea on Soil Greenhouse Gas Emissions in an Open-Field Lettuce System.

Controlled-release urea (CRU) fertilizers are widely used in agricultural production to reduce conventional nitrogen (N) fertilization-induced agricultural greenhouse gas emissions (GHGs) and improve N use efficiency (NUE). However, the long-term effects of different CRU fertilizers on GHGs and crop yields in vegetable fields remain relatively unexplored. This study investigated the variations in GHG emissions at four growth stages of lettuce in the spring and autumn seasons based on a five-year field experiment in the North China Plain. Four treatments were setup: CK (without N application), U (conventional urea-N application), ON (20% reduction in urea-N application), CRU (20% reduction in polyurethane-coated urea without topdressing), and DCRU (20% reduction in polyurethane-coated urea containing dicyandiamide [DCD] without topdressing). The results show that N application treatments significantly increased the GHG emissions and the lettuce yield and net yield, and DCRU exhibited the lowest N2O and CO2 emissions, the highest lettuce yield and net yield, and the highest lettuce N content of the N application treatments. When compared to U, the N2O emission peak under CRU and DCRU treatments was notably decreased and delayed, and their average N2O emission fluxes were significantly reduced by 10.20-20.72% and 17.51-29.35%, respectively, leading to a significant reduction in mean cumulative N2O emissions during the 2017-2021 period. When compared to U, the CO2 fluxes of DCRU significantly decreased by 8.0-16.54% in the seedling period, and mean cumulative CO2 emission decreased by 9.28%. Moreover, compared to U, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of the DCRU treatment was significantly alleviated by 9.02-17.13% and 16.68-20.36%, respectively. Compared to U, the N content of lettuce under DCRU was significantly increased by 6.48-17.25%, and the lettuce net yield was also significantly increased by 5.41-7.71%. These observations indicated that the simple and efficient N management strategy to strike a balance between enhancing lettuce yields and reduce GHG emissions in open-field lettuce fields could be obtained by applying controlled-release urea containing DCD without topdressing.

Modeling e‐Truck adoption for sustainable transport in Jordan: A system dynamics approach

AbstractThis study has developed a model that predicts the quantity of CO2 emissions reduced and the adoption of e‐Trucks until the year 2100 in Jordan. Using system dynamics software (Powersim) and business intelligence tools (Microsoft Power BI), the most significant factors affecting three modules: environment, government, and customer were examined. Twelve scenarios were modeled during the study (three factors and four cases for each factor). The factors were marketing effectiveness, environmental awareness, and government acquisition subsidy, and their values were (0.2, 0.3, 0.4, 0.5), (0.3, 0.4, 0.5, 0.6), and (500, 1500, 3000, 6000 Jordanian Dinar—JOD), respectively. Under normal conditions, with a marketing effectiveness of 0.2, environmental awareness of 0.3, and a subsidy of 500 JOD, the annual sales of e‐Trucks and Conventional Fuel Trucks (CFT) will break‐even in 2052 in Jordan. The cumulative CO2 emissions reduction at the same year will be 6165.213 Tons. Among the three factors, marketing effectiveness was found to have the highest impact followed by the environmental awareness and last came the acquisition subsidy. Based on our findings, it is recommended that policymakers prioritize improving marketing efforts to accelerate the shift towards e‐Trucks, raise environmental awareness among consumers, and provide subsidies for acquisition of e‐Trucks in Jordan. Additionally, further research is needed to incorporate other factors, such as ICT infrastructure, technology maturity and other social factors that can affect the adoption of e‐Trucks. The study's originality lies in its focus on e‐Trucks, a relatively underexplored area in the sustainable transport literature, especially in the context of Jordan as many other emerging nations. The practical implications include leading the switch to e‐Trucks, identifying infrastructural needs, and informing legislative choices. By analyzing long‐term dynamics and encouraging the deployment of e‐Trucks, it seeks to lower CO2 emissions, enhance air quality, and promote a sustainable transportation system in Jordan.

Tracing environmental footprint of copper wire rod manufacturing in China

Copper wire rod (CWR) is an indispensable processed material for electrification. However, CWR's environmental impacts and emission reduction pathway haven't been clearly investigated, especially for China where most CWRs are produced. This study quantified provincial environmental impacts and emission reduction potentials of China CWR manufacturing. Key findings are: (1) Most of gate-to-gate environmental impacts of CWR come from energy use, including electricity and natural gas; (2) 42 % of Global Warming Potential of CWR manufacturing can be reduced by electricity transition and energy efficiency increase; (3) There are regional disparities in the environmental impacts and emission reduction potentials of CWR, due to the differences in regional electricity structure, energy efficiency, and production capacities; (4) Cumulative carbon emission reduction of China CWR industry during 2022–2050 can reach 22 Mt CO2 eq., of which Jiangsu, Jiangxi, Anhui, and Guangdong provinces totally account for 71 %. This study supports the green transition of CWR industry.

Analysis of carbon neutrality technology path selection in the steel industry under policy incentives

As an energy-intensive industry, the steel industry incentivizes carbon neutrality technology innovation through carbon neutrality policies, thereby promoting the industry's low-carbon transformation. However, how policy promotes technological innovation in the steel industry to achieve net zero emissions is an urgent practical and theoretical problem that needs to be solved. This study constructs a comprehensive model that combines steel demand forecasting, technology evaluation, and bottom-up technology selection models. Described the cost-effectiveness of emission reduction technologies from a technical and economic perspective, quantitatively analyzed the emission reduction potential and evolution path of carbon neutrality technology under policy incentives in the steel industry, and provided policy support and specific deployment time for different technologies. The results indicate that under the scenario of strong subsidies and carbon prices, by 2060, the share of traditional long-process steelmaking was only 25 %, and the CO2 emissions per unit of crude steel were 0.88t CO2/t. At the same time, the implementation of policies has increased the cumulative emission reduction of the steel industry by 1.56 times from 2022 to 2060.

Analysis of carbon emission drivers and peak carbon forecasts for island economies

Sea islands are an essential support for expanding the blue economic space, and the study of the carbon emissions of Changhai County's island economies and their carbon peaking time is of great significance for achieving the goal of building an ecological low-carbon demonstration island with northern characteristics in Changhai County. In this study, the Logarithmic Mean Divisia Index (LMDI) method was used to explore the three main drivers affecting the carbon emissions of the island economies in Changhai County. The carbon emissions of Changhai County in 2012–2019 were estimated through the system dynamics model. The low-carbon development path and possible carbon peak time of Changhai County in 2020–2035 were predicted. The results show that: ①The urban system is the first positive driver of carbon emissions, followed by the residential system, and finally, the fishery system, the energy structure effect is the main positive driving effect affecting carbon emissions, and the population effect always shows a negative inhibitory impact on carbon emissions. ②The activities on the islands of Changhai County in 2012–2019 cumulatively produced 167.53 × 104 t of carbon emissions, 46.83 × 104 t of carbon sinks, and their net carbon emissions were 120.69 × 104 t. The results of the future scenario projections show that neither non-intervention nor a single policy of only adjusting land use and transport can achieve minor carbon emissions and that the best path for future low-carbon development in Changhai County is to develop all kinds of activities in a low-carbon (L) mode. ④Among the future forecast scenarios, Scenario 5 is an ideal model for the fastest way to achieve carbon peak, which generates 318.39 × 104 t of carbon emissions, and the cumulative emission reduction reaches 26.37 × 104 t.

Technical and economic analysis of a multicarrier building energy hub concept with heating loads at different temperature levels

Integration of renewable and waste energy sources, decentralisation, electrification and energy storage, are key pillars of energy transition in the district heating sector. Such a strategy can be implemented at the building level using the multi-carrier energy hub concept, which has recently gained popularity. This paper presents a technical and financial feasibility study of a building-integrated multi-carrier energy hub concept. The case study is performed for an existing large medical centre, where demand occurs simultaneously for electricity, cold, and heat at different temperature levels, including hot process water and steam. The central idea is to replace the high-exergy steam with heat from the municipal district heating network. The concept also includes the integration of heating and cooling loads, heat storage and implementation of an on-site photovoltaic (PV) power plant. The key components of the proposed hub technological structure are high-temperature heat pumps. Five alternative structures of the system configuration are examined using an hour-by-hour annual simulation. The results reveal that the proposed multi-carrier energy hub is fully operational. The project is also profitable, which results mainly from significant energy savings compared to the existing heat supply system using high-pressure steam. However, the profitability strongly depends on the system configuration, and the choice of the best option is ambiguous. The system with heat storage reaches the highest net present value (NPV) while the one without the storage results in the highest internal rate of return (IRR) due to significantly lower capital expenditures (CAPEX). In all cases, the project leads to a considerable cumulative CO2 emissions reduction, which is at the level of 1351 up to 2961 tons annually depending on system configuration.

Carbon Emission Projection and Carbon Quota Allocation in the Beijing–Tianjin–Hebei Region of China under Carbon Neutrality Vision

Supported by the coordinated development strategy, the Beijing–Tianjin–Hebei (BTH) region has achieved rapid development but also faces severe energy consumption and environmental pollution problems. As the main responsibility of emission reduction, the coordinated and orderly implementation of carbon emission reduction in Beijing, Tianjin, and Hebei is of great significance to the realization of the carbon neutrality target. Based on this, this study comprehensively uses the expanded STIRPAT model, optimized extreme learning machine (ELM) network, entropy method, and zero-sum gains DEA (ZSG-DEA) model to explore the carbon emission drivers, long-term emission reduction pathway, and carbon quota allocation in the BTH region. The results of the driving factor analysis indicate that the proportion of non-fossil energy consumption is a significant driving factor for Beijing’s carbon emissions, and the improvement of the electrification level can inhibit the carbon emissions. The total energy consumption has the greatest impact on the carbon emissions of Tianjin and Hebei. The simulation results reveal that under the constraint of the carbon neutrality target, Beijing, Tianjin, and Hebei should formulate more stringent emission reduction measures to ensure that the overall carbon emission will reach its peak in 2030. The cumulative emission reduction rate should exceed 60% in 2060, and negative carbon technology should be used to offset carbon emissions of not less than 360 million tons (Mt) per year by 2060. Furthermore, the allocation results show that Beijing will receive a greater carbon quota than Hebei. The final allocation scheme will greatly promote and encourage carbon emission reduction in Hebei Province, which is conducive to achieving the goal of carbon neutrality.

A slow-release fertilizer containing cyhalofop-butyl reduces N2O emissions by slowly releasing nitrogen and down-regulating the relative abundance of nirK

To simplify the process of the application of fertilizers and herbicides for farmers, a slow-release fertilizer containing cyhalofop-butyl (SFC) was developed to prolong the combined effect of the herbicide-fertilizer and achieve a synergistic effect on weeding and reducing N2O emissions. A greenhouse pot experiment was conducted using five treatments: CK (no fertilizer), CF (compound fertilizers), FC (fertilizers combined with cyhalofop-butyl), FF (film-coated compound fertilizers), and SFC (a slow-release fertilizer containing cyhalofop-butyl). The findings indicated that SFC exhibited the lowest N2O emissions, the highest paddy yield, and the highest nitrogen utilization rate among all the treatments. When compared to CF, the nitrogen release was notably delayed, leading to a significant reduction in cumulative N2O emissions under FF and SFC. When compared to CF, N2O emissions under FC were significantly decreased, suggesting that cyhalofop-butyl exerted a reduction role in N2O emissions. The SFC-treated nirK abundance was significantly lower than FF and FC, suggesting that the cyhalofop-butyl of SFC interacted with film of SFC inhibited the denitrification process in the paddy soil. Thus, the SFC reduced N2O emissions by slowing nitrogen release and down-regulating the relative abundance of nirK.

Global iron and steel plant CO2 emissions and carbon-neutrality pathways.

The highly energy-intensive iron and steel industry contributed about 25% (ref. 1) of global industrial CO2 emissions in 2019 and is therefore critical for climate-change mitigation. Despite discussions of decarbonization potentials at national and global levels2-6, plant-specific mitigation potentials and technologically driven pathways remain unclear, which cumulatively determines the progress of net-zero transition of the global iron and steel sector. Here we develop a CO2 emissions inventory of 4,883 individual iron and steel plants along with their technical characteristics, including processing routes and operating details (status, age, operation-years etc.). We identify and match appropriate emission-removal or zero-emission technologies to specific possessing routes, or what we define thereafter as a techno-specific decarbonization road map for every plant. We find that 57% of global plants have 8-24 operational years, which is the retrofitting window for low-carbon technologies. Low-carbon retrofitting following the operational characteristics of plants is key for limiting warming to 2 °C, whereas advanced retrofitting may help limit warming to 1.5 °C. If each plant were retrofitted 5 years earlier than the planned retrofitting schedule, this could lead to cumulative global emissions reductions of 69.6 (±52%) gigatonnes (Gt) CO2 from 2020 to 2050, almost double that of global CO2 emissions in 2021. Our results provide a detailed picture of CO2 emission patterns associated with production processing of iron and steel plants, illustrating the decarbonization pathway to the net-zero-emissions target with the efforts from each plant.

Spatial patterns and environmental benefits of photovoltaic poverty alleviation programs in China

The photovoltaic poverty alleviation (PVPA) project in China integrates clean energy production into poverty reduction, gaining significant academic interest. However, a systematic assessment of the spatial distribution and emission reduction performance of existing PVPA power plants at the site level remains deficient. Based on comprehensive data collection and spatial visualization of all PVPA plants, we revealed spatial distribution patterns and estimates potential environmental benefits for each plant. During 2013–2019, the construction of approximately 180-thansand PVPA plants in China had resulted in an overall installed capacity of 21.77 GW. The spatial layout showed a decreasing trend from east to west, with distinct clusters at the border areas of different provinces. The cumulative emission reduction benefits amounted to 636 million tons, with large-scale solar photovoltaics and the North China Grid contributing significantly. Emission reduction efficiency per unit of installed capacity in the north was higher than the south. This study provides an initial site-level assessment of the PVPA program in China and emphasizes the need for integrating economic feasibility and environmental benefits, along with developing complementary policies and exploring innovative “photovoltaic plus” channels tailored to local contexts in the future.

Systematic hyperparameter selection in Machine Learning-based engine control to minimize calibration effort

For automotive powertrain control systems, the calibration effort is exploding due to growing system complexity and increasingly strict legal requirements for greenhouse gas and real-world pollutant emissions. These powertrain systems are characterized by their highly dynamic operation, so transient performance is key. Currently applied control methods require tuning of an increasing number of look-up tables and of parameters in the applied models. Especially for transient control this state-of-the-art calibration process is unsystematic and requires a large development effort. Also, embedding models in a controller can set challenging requirements to production control hardware. In this work, we assess the potential of Machine Learning to dramatically reduce the calibration effort in transient air path control development. This is not only done for the existing benchmark controller, but also for a new preview controller. In order to efficiently realize preview, a strategy is proposed where the existing reference signal is shifted in time. These reference signals are then modeled as a function of engine torque demand using a Long Short-Term Memory (LSTM) neural network, which can capture the dynamic input–output relationship. A multi-objective optimization problem is defined to systematically select hyperparameters that optimize the trade-off between model accuracy, system performance, calibration effort and computational requirements. This problem is solved using an exhaustive search approach. The control system performance is validated over a transient driving cycle. For the LSTM-based controllers, the proposed calibration approach achieves a significant reduction of 71% in the control calibration effort compared to the benchmark process. The expert effort and turbocharger experiments used in calibrating transient compensation maps in physics-based feedforward controller are replaced by little simulation time and parametrization effort in ML-based controller, which requires significantly less expert effort and system knowledge compared to benchmark process. The best trade-off between multi-objective cost terms is achieved with one layer and 32 cells LSTM neural network for both non-preview and preview control. For non-preview control, a comparable control system performance is achieved with the LSTM-based controller, while 5% reduction in cumulative NOx emissions and similar fuel consumption is achieved with preview controller.

The Macroeconomic Impact of Europe’s Carbon Taxes

We estimate the macroeconomic impacts of carbon taxes on GDP and employment growth rates using 30 years of data on carbon taxation in various European countries. We find no evidence for a negative impact on employment or GDP growth but rather find a zero to modest positive impact. We also find a cumulative emissions reduction on the order of 4 to 6 percent for a $40/ton CO2 tax covering 30 percent of emissions. Reductions would likely be greater for a broad-based US carbon tax since European carbon taxes typically do not cover those sectors with the lowest marginal abatement costs. (JEL E23, E24, H23, Q54, Q58)

An appraisal of the utility of biochar in a rotation involving tobacco–rice in southern China

AbstractThe employment of biochar in crop production can not only improve soil quality, but also helps the field ecosystem to fix carbon and reduce emissions. Although the benefits of their application in crop production have been more and more confirmed, it is not clear when it comes to the acidic soil of tobacco and rice rotation. A tobacco–rice rotation experiment was conducted in southern China to probe the application value of biochar under these conditions. Three biochar application rates were employed in this experiment. BC0 (without biochar), BC25 (25 t ha−1), and BC50 (50 t ha−1). The findings show that biochar significantly boosted soil fertility and crop yields. Meanwhile, the soil organic carbon of tobacco rice rotation field with biochar increased by 31.76%. After a whole growth period of tobacco and rice, the cumulative emission reduction of CO2 and N2O from the soil by biochar were 15,944 kg ha−1 and 1810 g ha−1, respectively. The use of biochar not only significantly improved the bacterial diversity of tobacco and rice rotation soil, but also altered the original microbial community structure. The profusion of Proteobacteria and Acidobacteria was reduced and the abundance of Actinobacteria and Bacteroidetes was enhanced in the treatments with biochar. Among them, Sphingomonadales, Planctomycotes, and Ktedonobacteria, which are beneficial to plant growth and soil health, have become key phylotypes. The carbon balance analysis data show that the net carbon sequestration of the two treatments with biochar is positive, while that of the treatment without biochar is negative. In terms of economic benefit, the application of biochar increased the average of 2.055 CNY kg−1 consumed energy (CE) in the whole tobacco–rice rotation system. The ecological benefit was 0.51 kg C kg−1 CE. In conclusion, biochar can be effectively used in the practice of tobacco–rice rotation and acidic soil improvement in southern China.

Trade-Offs between Direct Emission Reduction and Intersectoral Additional Emissions: Evidence from the Electrification Transition in China's Transport Sector.

Electrifying the transport sector is crucial for reducing CO2 emissions and achieving Paris Agreement targets. This largely depends on rapid decarbonization in power plants; however, we often overlook the trade-offs between reduced transportation emissions and additional energy-supply sector emissions induced by electrification. Here, we developed a framework for China's transport sector, including analyzing driving factors of historical CO2 emissions, collecting energy-related parameters of numerous vehicles based on the field- investigation, and assessing the energy-environment impacts of electrification policies with national heterogeneity. We find holistic electrification in China's transport sector will cause substantial cumulative CO2 emission reduction (2025-2075), equivalent to 19.8-42% of global annual emissions, but with a 2.2-16.1 GtCO2 net increase considering the additional emissions in energy-supply sectors. It also leads to a 5.1- to 6.7-fold increase in electricity demand, and the resulting CO2 emissions far surpass the emission reduction achieved. Only under 2 and 1.5 °C scenarios, forcing further decarbonization in the energy supply sectors, will the holistic electrification of transportation have a robust mitigation effect, -2.5 to -7.0 Gt and -6.4 to -11.3 Gt net-negative emissions, respectively. Therefore, we conclude that electrifying the transport sector cannot be a one-size-fits-all policy, requiring synergistically decarbonization efforts in the energy-supply sectors.

Combined Effects of Biochar and Inhibitors on Greenhouse Gas Emissions, Global Warming Potential, and Nitrogen Use Efficiency in the Tobacco Field

Biochar (BC), nitrification inhibitors (methyl 3-(4-hydroxyphenyl) propionate, MHPP), and urease inhibitors (n-butyl phosphorothioate triamine, NBPT) have emerged as effective soil greenhouse gas (GHG) mitigation strategies in agroecosystems. However, the combined use of BC and inhibitors in karst areas has no available data. Therefore, the combined effects of BC, MHPP, and NBPT on GHG emissions, global warming potential (GWP) and nitrogen use efficiency (NUE) in roasted tobacco cropping systems were studied to improve the understanding in climate mitigation. CO2, CH4, and N2O emissions from soils were measured using static chamber-gas chromatography. Results showed that the combined use of BC and inhibitors significantly increased soil total nitrogen, available potassium, electric conductivity, pH, and soil organic matter compared to the control. The combined use of BC and MHPP or NBPT significantly increased cumulative soil CO2 emissions by 33.95% and 34.25%, respectively. The exponential–exponential function of soil CO2 fluxes with soil moisture and temperature demonstrated good fit (R2: 0.506–0.836). The combination of BC and NBPT increased the cumulative soil CH4 emissions by 14.28% but not significantly compared to the fertiliser treatment. However, the combination of BC and MHPP resulted in a significant reduction in cumulative soil CH4 emissions by 80.26%. In addition, the combined use of BC and MHPP or NBPT significantly reduced the cumulative soil N2O emissions by 26.55% and 40.67%, respectively. The inhibition effect of NBPT was better than MHPP. Overall, the combined use of BC and inhibitors significantly reduced the yield-scaled GWP, markedly increased crop yield and NUE, and mitigated climate change in the southwest karst region.

HCFC-141b (CH3CCl2F) Emission Estimates for 2000–2050 in Eastern China

HCFC-141b (CH3CCl2F) has dual environmental impacts on ozone depletion and climate change, with the ozone depletion potential of 0.11 and the global warming potential of 782, and its emissions has attracted international attention. Under the control of the Montreal Protocol, China should phase out the production and consumption of HCFC-141b by 2030. This study firstly estimated the HCFC-141b emissions in eastern China based on the bottom-up method during 2000-2019. The results show that the HCFC-141b emissions in eastern China increased from 0.4 Gg yr-1 in 2000 to 7.1 Gg yr-1 in 2019, and there was a bank of 253.6 Gg in PU foam products in 2019, which may have an impact on future the HCFC-141b emissions. In addition, the HCFC-141b emissions were predicted in eastern China from 2020-2050 under the baseline scenario (BAU), the Montreal Protocol scenario (MP), and the accelerated phase-out scenario (AP), and the emission potential was analyzed. The results show that the HCFC-141b emissions increased rapidly under the BAU scenario, with cumulative emissions of 1162.6 Gg in 2020-2050. Under the MP and AP scenarios, the cumulative HCFC-141b emission reduction potential from 2020 to 2050 are 1002.1 Gg (equivalent to 110.2 Gg CFC-11-eq and 783.6 Tg CO2-eq) and 1034.8 Gg (equivalent to 113.8 Gg CFC-11-eq and 809.2 Tg CO2-eq), respectively. Compared with the MP scenario, under the AP scenario, eastern China will get an additional emission reduction potential of 32.7 Gg (equivalent to 3.6 Gg CFC-11-eq and 25.5 Tg CO2-eq) during 2020-2050, which will make greater contributions to protecting the ozone layer and mitigating climate change.