Net GHG Emissions Research Articles

Life Cycle Assessment of Resource-Oriented Sanitation Based on Vacuum Toilet and Vacuum Kitchen Waste Shredder: A Case Study in Rural Southeastern China

The resource value of feces and kitchen waste has not been fully emphasized and utilized in rural sanitation management in China. In this paper, we propose a new ecological sanitation model with the core technology of “vacuum toilet and vacuum kitchen waste shredder—vacuum collection—resource treatment”, i.e., the modern home–farm cycle sanitation (MHFCS) system. We compared the environmental performance of the MHFCS system with that of a typical end-pipe treatment sanitation (EPTS) system (Johkasou—small onsite wastewater treatment system) in rural China using a life cycle assessment (LCA) approach. The results showed that the main source of environmental impacts of the MHFCS system was the collection and treatment process of domestic organic liquid wastes; the greenhouse gas emissions were 64.543 kg CO2eq·PE−1·year−1, and the MHFCS system indirectly gained a fertilizer substitution benefit of 65.960 kg CO2eq·PE−1·year−1 through nutrient element recycling. The MHFCS system has significant advantages in terms of net GHG emissions. Sensitivity analyses showed that resource consumption of vacuum facilities was a key factor for the MHFCS system. This system offers the potential to break down the barriers of the EPTS system in order to meet environmental sustainability and market demands for systemic diversity.

Enhancing Agricultural Soil Carbon Sequestration: A Review with Some Research Needs

The US rejoined the Paris Agreement in 2021 with a targeted 50–52% reduction in net GHG emissions in 2030 relative to 2005. Within the US’s nationally determined contributions, several land-based mitigation options were submitted, targeting the removal of 0.4–1.3 GtCO2 yr−1 in 2030 compared to the net flux in 2010. Acknowledging disagreement has existed on both technological and economic feasibility levels of soil C sequestration adoption and practices, this review explores and evaluates the research findings and needs for six concepts: (1) permanence; (2) additionality; (3) leakage; (4) uncertainty; (5) transaction costs; and (6) heat-trapping ability of different gases. These concepts are crucial for the effective implementation of soil C sequestration projects since they help establish robust and integrated methodologies for measurement, verification, and issuance of carbon credits. In turn, they help ensure that environmental, social, and economic benefits are accurately assessed and credibly reported, enhancing the integrity of carbon markets and contributing to global climate mitigation efforts. This review also evaluates the existing and potential market opportunities for agricultural production with C sequestration and “climate- smart” farming practices. Current barriers to, research needs for, and policy considerations regarding soil C sequestration strategies are also stated.

GCoM datasets: a collection of climate and energy action plans with mitigation, adaptation and energy access commitments

This paper presents a collection of datasets holding information on the energy and climate action plans of 6,850 municipalities, taking part in the transnational initiative of the Global Covenant of Mayors (GCoM). This collection includes commitments for reducing net GHG emissions by at least 20% by 2020, 55% by 2030 and becoming climate neutral by 2050. The signatories commit to addressing any of the three pillars of the initiative, namely climate change mitigation, adaptation and energy access. Following two previous releases, the third release of the GCoM collection is introduced, with closing date September 2022. The datasets include information on the action plans and monitoring reports as they are self-reported by signatories, undergoing a quality-harnessing procedure before publication. Additionally, an external comparison is developed with the Emissions Database for Global Atmospheric Research (EDGAR v7), controlling for comparable sources and activity sectors, ensuring the usability of the GCoM datasets for relevant research on local policies and their effects on reducing the impact of climate change.

Management of excavated soil and dredging spoil waste from construction and demolition within the EU: Practices, impacts and perspectives

Excavated soil and rock (ESR) and dredging spoils (DDS) account for 23 % of the total EU waste generation in 2020. This study performs a life cycle assessment and life cycle costing to quantify the potential environmental and cost savings resulting from increasing the level of ESR and DDS prepared for reuse and recycled in comparison to the business-as-usual practice. Scenarios for the waste management pathways based on the status quo, technical feasibility or normative impositions are assessed, including the potential contribution to achieving the European Green Deal goals. Results show that promoting preparing for reuse and recycling could lead to non-negligible GHG reductions (up to 3.6 Mt. CO2 eq.) and economic savings (EUR 12.3 billion) annually. Depending upon the scenario, 0.2 % to 1 % of the net annual GHG emissions reductions sought by the European Green Deal could be facilitated by scaling up improved circular management of ESR and DDS at the EU level. Finally, the study highlights the main barriers to scaling up to more circular (i.e., preparing for reuse and recycling) and better performing management options in Europe. The results provide new insights for the European Green Deal and circular economy policymaking for CDW.

Changes in soil N2O emissions and nitrogen use efficiency following long-term soil carbon storage: Evidence from a mesocosm experiment

Policy and market incentives are rapidly expanding to promote soil organic carbon (SOC) sequestration in global croplands. Evidence suggests that long-term increases in SOC can influence both crop yield and nitrogen (N) fertilizer requirements, with the potential to help address two important sustainability challenges. However, increases in SOC may also trigger higher soil nitrous oxide (N2O) emissions, which would represent an important tradeoff for climate change mitigation. We tested the hypothesis that long-term increases in SOC are associated with higher crop yields and fertilizer N use efficiency (NUE), but at the cost of higher N2O emissions. Wheat was grown in two soils (SOClow and SOChigh) under three N fertilizer rates (0, 100, and 200 kg N ha−1) in a mesocosm experiment. Soils were obtained (0–25 cm) from a 22-yr field experiment on no-till and cover cropping in California. Results indicate that total biomass and grain yield were higher for SOClow than SOChigh at 100 kg N ha−1 but not the other N levels. Crop N uptake was also 28% greater for SOClow at 200 kg N ha−1, resulting in higher overall NUE. Soil N2O emissions increased for SOChigh by 25–112% compared to SOClow, likely due to long-term changes in labile C and N pools, microbial activity, and soil structure influencing porosity and gas diffusion. While there are well-documented crop and environmental benefits from enhancing SOC in agricultural soils, results from this study suggest that changes in soil N2O emissions should be considered to accurately determine net GHG emission reductions.

Saving farm subsidies with smart climate interventions: the case of transition to a millet-based agriculture

PurposeThe study attempts to estimate farm subsidies the governments can save by transitioning to a millet-based production system, replacing GHG emission-intensive crops.Design/methodology/approachIt updates a 131 × 131 commodity input–output (IO) table of the year 2015–16 into 2021–22 using the RAS procedure and simulates the economy-wide impacts of replacing rice and wheat with pearl millet and sorghum using consumption and production approaches. It then quantifies fertilizer, electricity and credit subsidy expenses the government can save through this intervention. It also estimates the potential reduction in GHG emissions that the transition could bring about. India is taken as a case.FindingsResults show pearl millet expansion brings greater benefits to the government. It is estimated that when households return to their pearl millet consumption rates that prevailed in the early-reform period, this could save the Indian government Rs. 622 crores (USD 75 m). The savings shall be reinvested in agriculture to finance climate adaptation/mitigation efforts, contributing to a sustainable food system. Net GHG emissions also decline by 3.3–3.6 MMT CO2e.Practical implicationsIndian government has been actively aiming to bring down paddy areas since 2013–14 through the Crop Diversification Program and promoting millets (and pulses and oilseeds) on these farms. The prime reason is to check rapidly declining groundwater irrigation in Green Revolution states. Regulations in the past in these states have not brought the intended results. Meanwhile, electricity and fertilizers are heavily subsidized for agriculture. A slight shift in the cropping system can help conserve these resources. Meanwhile, GHG emissions could also be brought down and subsidies could well be saved. The results of the study indicate the same.Social implicationsA less warm society is what governments and nongovernment organizations across the world are aiming for at present. Financial implications affect actions against climate change to a greater extent, apart from technological innovations. The effects of policy strategies discussed in the study, taking a large country as a case, when implemented appropriately around the regions, could help move a step closer to action against climate change.Originality/valueThe paper addresses a key but rarely explored research issue – that how a climate-sensitive crop choice will help reduce the government’s fiscal burden to finance climate adaption/mitigation. It also offers a mechanism to estimate the benefits within an economy-wide framework.

Meeting national land use related objectives while safeguarding typical landscapes

Landscapes play a significant role in the regional development by providing ecosystem services to the local communities. Significant changes in land management due to the political decisions may significantly change the typical landscape in rural areas. Therefore, the aim of this study is to explore how to use the landscape differences to facilitate achievement of national socio-economic and environmental objectives, while avoiding significant changes and safeguarding typical landscapes. Cluster analysis was used to identify relatively homogeneous groups with four socio-economic and environmental indicators, namely, profit, employment, net GHG emissions, habitat quality. Results show that clusters with the highest socio-economic return are located closest to the capital city and carbon sequestration measures may be concentrated in the landscapes that are geographically farthest from the capital city, but then the abandonment of rural areas and the disappearance of typical landscapes may occur. The political decisions related to land use change should be adapted to the specific landscape, so that not only socio-economic and environmental objectives are achieved together with the fulfilment of international obligations, but also the typical landscape of the specific landscape region is preserved.

The economic and environmental sustainability of converting Miscanthus to hydrocarbon biofuel by pyrolysis and catalytic hydrotreatment

Utilization of high-quality biomass resources such as Miscanthus is considered an effective way to alleviate energy shortages and develop a low-carbon energy economy. In this work, the economic benefits and environmental impacts of producing hydrocarbon biofuel by fast pyrolysis and catalytic hydrotreatment from Miscanthus were investigated, along with the differences in the utilization of biochar: combustion for heat supply (HS), soil amendment (SA) and upgrading to activated carbon (AC). The hydrocarbon biofuel mass yields of up to 23.3 % for all scenarios. The SA scenario had the lowest selling price of 6.89 Chinese Yuan (CNY) per liter. The HS scenario had the lowest total GHG emissions and fossil energy requirement (FED) of 19.2 gCO2e/MJ and 0.615 MJ/MJ, respectively. The AC scenario had the best net GHG emissions of −46.2 gCO2/MJ due to the replacement of the coal-based activated carbon pathway, but the higher energy consumption and capital investment limit its economic performance. Sensitivity analysis showed that fuel output had the most significant economic and environmental impacts. Optimizing the financing cost and system energy supply was a feasible and effective way to improve the economic and environmental sustainability of the bio-energy plant.

Renewable-Energy-Based Microgrid Design and Feasibility Analysis for King Saud University Campus, Riyadh

The world is forced to think about alternate energy sources because fossil fuel stocks are unreliable, harmful, and depleting quickly. Deployments of microgrids powered by renewable energy are some of the most economical, effective, dependable, and sustainable answers to this problem. The design of a power system with the least amount of economic and environmental impact is the main challenge because the world is currently facing climate change disasters on a scale that has never been seen before. As a result, there is an urgent need to transition to renewable energy resources to meet energy demands. This study examines the creation of a hybrid microgrid to meet the electrical load requirements of the King Saud University campus in Riyadh by utilizing the site’s solar and wind potential. A software called HOMER Pro Version 3.14.5 is used to simulate the planned microgrid system. The software can run numerous simulations while taking into account various system configurations. The ultimate objective is to choose the best combination of different power sources to create a microgrid with low energy costs, dependability, minimal GHG emissions, and a high penetration of renewable energy. The solar, wind, and battery system connected to the grid was shown to be the most advantageous choice in terms of cost of energy (COE), net present cost (NPC), operational costs, and GHG emissions after the software ran numerous simulations. The most economically advantageous way to meet the load demands of a university campus while still achieving more than 82% renewable penetration is to use an optimal system architecture. In this study, the ideal system configuration is subjected to sensitivity analysis to confirm the system’s performance. This optimal system design is used as a benchmark for examining the potential usage of renewable energy in the education sector in Saudi Arabia in particular and in any educational facility worldwide in general.

Fire-killed forest biomass for mills and communities and bioenergy GHG impacts

We examine the supply chains of post-fire salvage harvest to 28 mills or 10 communities in British Columbia, Canada, and assess the net change in GHG emissions for community bioenergy and biofuels, relative to a ‘do-nothing’ baseline with fossil fuel use.Lowest-cost supply chains for post-fire salvage had largest hauled biomass for mills in the southern interior of the province, with mills in close proximity to each other having small fibresheds and low haul costs. Supply chains were also quantified for salvage biomass hauled to communities by using a lowest GHG optimization routine that selected between liquid transportation fuels or community bioenergy (heat and/or electricity). For the first few decades, avoided GHG emissions were larger when biomass was used for bioenergy (heat and/or electricity), mainly in larger communities, to avoid fossil fuel burning. As energy systems decarbonized, biomass was used for biofuels, and production was more evenly distributed amongst the communities.Adding these results to an integrated framework with previously published ecosystem emissions and removals assessed the net change in GHG emissions for a post-fire rehabilitation and bioenergy scenario relative to a ‘do-nothing’ baseline with continued fossil fuel use. We found that there was an initial increase in net GHG emissions even though biogenic emissions from bioenergy were partially offset by avoided fossil fuel emissions. Over time, an enhanced sink from rehabilitation activities combined with avoided fossil fuel emissions resulted in a cumulative (2020–2070) GHG reduction at median levels of −6 TgCO2e with a range from reduced emissions of −39 TgCO2e to increased emissions 37 TgCO2e. Cumulative avoided fossil emissions were −62 TgCO2e with a range from −49 TgCO2e to −86 TgCO2e.

Triple-zero tillage and system intensification lead to enhanced productivity, micronutrient biofortification and moisture-stress tolerance ability in chickpea in a pearlmillet-chickpea cropping system of semi-arid climate

Pearlmillet-chickpea cropping system (PCCS) is emerging as an important sequence in semi-arid regions of south-Asia owing to less water-requirement. However, chickpea (dry-season crop) faces comparatively acute soil moisture-deficit over pearlmillet (wet-season crop), limiting overall sustainability of PCCS. Hence, moisture-management (specifically in chickpea) and system intensification is highly essential for sustaining the PCCS in holistic manner. Since, conservation agriculture (CA) has emerged is an important climate-smart strategy to combat moisture-stress alongwith other production-vulnerabilities. Hence, current study comprised of three tillage systems in main-plots viz., Complete-CA with residue retention (CAc), Partial-CA without residue-retention (CAp), and Conventional-tillage (ConvTill) under three cropping systems in sub-plots viz., conventionally grown pearlmillet-chickpea cropping system (PCCS) alongwith two intensified systems i.e. pearlmillet-chickpea-fodder pearlmillet cropping system (PCFCS) and pearlmillet-chickpea-mungbean cropping system (PCMCS) in split-plot design. The investigation outcomes mainly focused on chickpea (dry-season crop) revealed that, on an average, there was a significant increase in chickpea grain yield under CAc to the tune of 27, 23.5 and 28.5% under PCCS, PCFCS and PCMCS, respectively over ConvTill. NPK uptake and micronutrient (Fe and Zn) biofortification in chickpea grains were again significantly higher under triple zero-tilled CAc plots with residue-retention; which was followed by triple zero-tilled CAp plots without residue-retention and the ConvTill plots. Likewise, CAc under PCMCS led to an increase in relative leaf water (RLW) content in chickpea by ~ 20.8% over ConvTill under PCCS, hence, ameliorating the moisture-stress effects. Interestingly, CA-management and system-intensification significantly enhanced the plant biochemical properties in chickpea viz., super-oxide dismutase, ascorbate peroxidase, catalase and glutathione reductase; thus, indicating their prime role in inducing moisture-stress tolerance ability in moisture-starved chickpea. Triple zero-tilled CAc plots also reduced the N2O fluxes in chickpea but with slightly higher CO2 emissions, however, curtailed the net GHG-emissions. Triple zero-tilled cropping systems (PCFCS and PCMCS) both under CAc and Cap led to a significant improvement in soil microbial population and soil enzymes activities (alkaline phosphatase, fluorescein diacetate, dehydrogenase). Overall, the PCCS system-intensification with mungbean (PCMCS) alongwith triple zero-tillage with residue-retention (CAc) may amply enhance the productivity, micronutrient biofortification and moisture-stress tolerance ability in chickpea besides propelling the ecological benefits under semi-arid agro-ecologies. However, the farmers should preserve a balance while adopting CAc or CAp where livestock equally competes for quality fodder.

Comparative life-cycle assessment of various harvesting strategies for biogas production from microalgae: Energy conversion characteristics and greenhouse gas emissions

Biogas production via anaerobic digestion is highly attractive in the realm of microalgae technology. However, the microalgae harvesting strategies for biogas production has yet to be comprehensively evaluated. Here, a comparative life-cycle assessment for microalgae harvesting scenarios of centrifugation (CT), sedimentation and centrifugation (SD-CT), flocculation and centrifugation (FC-CT), flocculation and electro-flotation (FC-EF) were conducted to evaluate the energy conversion characteristics and environmental impacts. The results showed that harvesting strategies significantly affected the net energy yield of the whole system. Only scenarios FC-CT and FC-EF achieved positive net energy yield of 0.17 and 0.04 MJ with 1 MJ net energy output. The net energy yield of scenarios SD-CT and CT were negative (−0.11 and −1.92 MJ) because of the low harvesting efficiency and high electricity consumption. The net GHG emissions of the four scenarios were all positive, and scenario FC-EF achieved the least GHG emissions (21.86 g CO2-eq MJ−1). According to the nutrient balance analysis of carbon, about 15 percent carbon from flue gas was fixed by microalgae in the form of soil fertilizer (9.32%) and biomethane product (5.63%–6.60%). Additionally, harvesting efficiency and biogas yield had the most profound impact on the parameters for two-step and one-step harvesting scenarios.

Integrated Assessment Modelling of Future Air Quality in the UK to 2050 and Synergies with Net-Zero Strategies

Integrated assessment modelling (IAM) has been successfully used in the development of international agreements to reduce transboundary pollution in Europe, based on the GAINS model of IIASA. At a national level in the UK, a similar approach has been taken with the UK Integrated Assessment Model, UKIAM, superimposing pollution abatement measures and behavioural change on energy projections designed to meet targets set for the reduction of greenhouse gas emissions and allowing for natural and imported contributions from other countries and shipping. This paper describes how the UKIAM was used in the development of proposed targets for the reduction of fine particulate PM2.5 in the UK Environment Act, exploring scenarios encompassing different levels of ambition in reducing the emissions of air pollutants up to 2050, with associated health and other environmental benefits. There are two PM2.5 targets, an annual mean concentration target setting a maximum concentration to be reached by a future year, and a population exposure reduction target with benefits for health across the whole population. The work goes further, also demonstrating links to social deprivation. There is a strong connection between climate measures aimed at reducing net GHG emissions to zero by 2050 and future air quality, which may be positive or negative, as illustrated by sectoral studies for road transport where electrification of the fleet needs to match the evolution of energy production, and for domestic heating, where the use of wood for heating is an air quality issue. The UKIAM has been validated against air pollution measurements and other types of modelling, but there are many uncertainties, including future energy projections.

Characterisation of biochar and estimation of net GHG emissions from Prosopis Juliflora biomass for soil and solid fuel application

Characterisation of biochar and estimation of net GHG emissions from Prosopis Juliflora biomass for soil and solid fuel application

International Collaborative Cluster-Based Carbon Sequestration Plan

The status quo climate change forecast was analyzed using the ENROADS software and indicates that the net GHG emissions could reach about 90 gigatons of CO2 equivalent by 2100, and global temperatures could rise by 3.6°C. This projection will likely be worse even with moderate estimates. The factors used in the reported status quo forecasts are optimistic. From energy mix to population growth and the assumption that gas use could increase while oil declines, this scenario is limited by available gas reservoirs. There needs to be a more aggressive application of CCS to reach Net-Zero by 2050. Carbon Capture and Storage (CCS) has been identified as the leading technology that could help reduce the amount of CO2 emitted into the atmosphere. At the same time, the search for non-fossil fuel energy sources continues. The amount of CO2 dilution in the air stream complicates the economics of direct air capture. This research proposes two international collaborative clusters for India. Due to India's growth and use of fossil energy sources, this is necessary to manage CO2 emissions from coal-fired plants. The results show that cluster-based CCS facilities possess great potential for the world to develop faster carbon capture and sequestration technology and deploy it faster. These cluster CCS systems will create economies of scale and integration necessary to make the CCS technology succeed to help reduce India's and global CO2 emissions from fossil-fuel-powered electricity generation. If CCS is deployed at the proposed scale, it will reduce atmospheric CO2 significantly, which would capture more than 250 times more than today's effort.

Analysis of the Effect of the Use of Food Waste Disposers on Wastewater Treatment Plant and Greenhouse Gas Emission Characteristics

The introduction of food waste disposers (FWDs) has been discussed in various countries, and in Korea, a method for utilizing FWDs has been considered. The results of the study show that the use of FWDs is more eco-friendly and economical than other forms of food waste (FW) disposal. However, there are also studies showing that FWDs are worse, for example, they aggravate water pollution and deteriorate the function of municipal wastewater treatment plants (WWTPs). Therefore, this study analyzed the concentration of pollutants of wastewater from FWD and the effect on the operation rate and GHG emission of WWTP when FW was introduced into the sewer by FWD using operation data for each WWTP. As a result of the analysis, when FWD was used, facilities exceeding the appropriate operation rate accounted for 86% of the total WWTP, and net-GHG emissions increased by 58%. Through this, FWD wastewater showed much higher contaminant concentrations than regular wastewater; thus, the introduction of FWD in the current situation will have a negative effect on maintaining the function of WWTP and reducing GHG. To introduce FWDs, improvement in WWTPs regarding pollutant load and discharge characteristics of FW and input of digestion systems through a separate FWD pipe, the introduction of high-efficiency energy facilities, and the recycling of wastewater sludge are necessary to reduce GHG emissions.

Contribution of carbon pricing to meeting a mid-century net zero target

ABSTRACT A mid-century net zero target creates a challenge for reducing the emissions of emissions-intensive, trade-exposed sectors with high cost mitigation options. These sectors include aluminium, cement, chemicals, iron and steel, lime, pulp and paper and petroleum refining. Available studies agree that decarbonization of these sectors is possible by mid-century if more ambitious policies are implemented soon. Existing carbon pricing policies have had limited impact on the emissions of these sectors because their marginal abatement costs almost always exceed the tax rate or allowance price. But emissions trading systems with free allowance allocations to emissions-intensive, trade-exposed sectors have minimized the adverse economic impacts and associated leakage. Internationally coordinated policies are unlikely, so implementing more ambitious policies creates a risk of leakage. This paper presents policy packages a country can implement to accelerate emission reduction by these sectors with minimal risk of leakage. To comply with international trade law the policy packages differ for producers whose goods compete with imports in the domestic market and producers whose goods are exported. Carbon pricing is a critical component of each package due its ability to minimize the risk of adverse economic impacts on domestic industry, support innovation and generate revenue. The revenue can be used to assist groups adversely impacted by the domestic price and production changes due to carbon pricing and to build public support for the policies. Key policy insights A country with a mid-century net zero GHG emission target likely will need to implement more ambitious mitigation policies soon for emission-intensive sectors such as aluminium, cement, chemicals, iron and steel, lime, pulp and paper and petroleum refining. More ambitious mitigation policies are likely to vary by country and be implemented at different times, creating a risk of leakage due to industrial production shifts to other jurisdictions. More ambitious mitigation policy packages, compatible with international trade law, that a country can implement to reduce emissions from these sectors with minimal risk of leakage are available but differ for producers whose goods compete with imports in the domestic market and those whose goods are exported. Carbon pricing is a critical component of each package due its ability to minimize the risk of adverse economic impacts on domestic producers, support innovation and generate revenue.

Cooperation between specialized cropping and livestock farms at local level reduces carbon footprint of agricultural system: A case study of recoupling maize-cow system in South China

Decoupling of crop and livestock production has become increasingly common in the world during to past decades. The cooperation between specialized crop and livestock farms have been paid more attention for the development of sustainable agriculture. This study assumed that rebuilding the linkage between specialized crop and livestock farms through cooperation at the local level would decrease agricultural GHG emissions. Therefore, we designed a cooperative crop-livestock farming model (CCLS) in South China by recoupling the cow farm with the sweet maize cultivation farms around it to demonstrate the hypothesis based on carbon footprint (CF) method. The CFs under two cooperative scenarios (CCLS20 and CCLS50) were compared with the corresponding decoupling models (DCLS20 and DCLS50). Results showed that CCLS significantly reduced GHG emissions from cropping systems in comparison to DCLS primarily by increasing the soil organic carbon storage while decreasing accumulative N2O emissions. In specific, the CFs of CCLS20 and CCLS50 were 48.78% and 623.34% lower than DCLS20 and DCLS50, respectively. The yield-based CFs of CCLS20 and CCLS50 were 66.30% and 165.99% lower than DCLS20 and DCLS50, respectively. Meanwhile, the CF of the cow farm in CCLS20 and CCLS50 were 8.80% and 8.22% lower than that in DCLS20/50 by lowering relative GHG emissions of straw supply in roughage forage and shortening manure storage time in the manure management process. Finally, the yield-based CF in CCLS20 and CCLS50 were 67.68% and 168.51% lower than the DCLS20 and DCLS50, respectively, demonstrating that the cooperation between specialized planting and livestock farms at local level reduced the CF of the agricultural production chain by the synergistic reduction effects of GHG emissions in cropland, livestock rearing and transportation processes. The results would provide a quantitative understanding of the net GHG emission of cooperative crop-livestock system at the local level in China and valuable information for the development of sustainable farming system in the world.

Nitrogen management to reduce GHG emissions while maintaining high crop productivity in temperate summer rainfall climate

Nitrogen (N) fertilizer management determines the productivity and environmental footprint of intensive wheat-maize double-cropping systems in the North China Plain (NCP). The N fertilizer application rate can be optimized by balancing the trade-off between crop productivity and N 2 O emissions. Applying more N fertilizer to wheat in the dry, cool winter season while less N to summer crops is expected to reduce the N 2 O emissions without scarifying yield, because summer crop (maize) will use the residual N fertilizer from the previous crop season (wheat) to maintain their productivity. We combined four years of experimental data and soil-plant system modeling to assess the productivity and greenhouse gas emissions resulting from various N fertilizer management strategies. The farming systems model APSIM was used to simulate the wheat-maize double cropping system with N fertilizer application rates of 0–920 kg N ha −1 yr −1 . The APSIM model explained 93% variation in biomass (RMSE = 0.88), 82% variation in soil mineral N (RMSE = 34.1), and 70% variation in N 2 O emission (RMSE = 1.37) measured in the experiment. The default IPCC emission factor (0.5% for the wheat season and 1.6% for the maize season) underestimated the N 2 O emission by 7.25 kg ha −1 when the local N fertilizer rates were applied (about 325 kg N ha −1 for wheat and 257 kg N ha −1 for maize). A N rate of 420 kg N ha −1 yr −1 would reduce GHG emission to the minimum (1.15 t CO 2 -eq ha −1 yr −1 ) while achieving more than 90% of the maximum grain yield. Additionally, allocating more N fertilizer to the wheat crop, while reducing the N fertilizer input for maize, did not significantly change grain yield of either crop, but further reduced net GHG emission by 1.07 t CO 2 -eq ha −1 yr −1 . The APSIM model describes the crop growth and soil N dynamics of a wheat-maize double cropping system that receives N fertilizer at rates up to 920 kg N ha −1 yr −1 . The site-specific modeling results indicate that appropriate N fertilizer management, i.e., adjusting the rate and time of N applications, can lower the net GHG emission without impacting crop yields. Our study provides a practical and reliable method to develop a "win-win" strategy for N fertilizer management in double-cropping systems. • There is a trade-off between crop yield and GHG emissions with N fertilizer use. • Long-term impact of N fertilizer use was deduced with a modelling approach. • Lowering N fertilizer rate could reduce GHG emissions while maintaining crop yield. • Allocating more N for wheat and less for maize is a further opportunity. • These scenarios should be used to develop a "win-win" N management strategy.

Enabling technologies assessment for reducing Italian LPT emissions on short and long-term time frames

The international policies on energy transition and sustainable development for mitigating global warming aim to limit the rise in global temperatures to 1.5°C and consequently to outline a transition towards zero greenhouse gas emissions (GHG) by 2050. Vehicular traffic is responsible for about 30% of the total direct GHG, making it one of the most critical sectors. The achievement of net zero GHG emission goal in transportation sector relies in both improving the energy efficiency of the actual vehicles and promoting more efficient modes of transport. In this context, the development and enhancement of local public transport (LPT) systems represent a key point for future mobility, due to the reduced consumption and emissions per unit of transported passenger. As a result, public transport companies need to take rapid action to modernize their fleets, which currently consist mostly of diesel buses, by introducing vehicles and fuels with a lower environmental impact. With reference to the bus transit component of LPT, this article provides an assessment of vehicle and energy enabling technologies for emission mitigation in Italian LPT in a short (2030) and medium-long term (2050) application time frame, in accordance with the EU policy objectives contained in the "Fitfor55" proposal. The study shows that achieving GHG reduction targets requires the use of a mix of technological solutions, both vehicular and energy. Some of them, reduced environmental benefits, are immediately exploitable, in terms of maturity and cost-effectiveness, while others, more promising, are based on less mature technologies, now more expensive, and on the use of energy vectors produced from renewable sources, for which a significant research and development effort is required.