Structural characteristics and drivers of greenhouse gas emissions at county-level and long-time scales: A case study of the Anji County, China

To achieve carbon neutrality, the Chinese government needs to gain a comprehensive understanding of the sources and drivers of greenhouse gas (GHG) emissions, particularly at the county level. Anji County in eastern China is a typical example of an industrial transformation from quarrying to a low-carbon economy. This study analyzed the decoupling types and structural characteristics of GHG emissions and the driving factors of carbon dioxide (CO2) emissions in the Anji from 2006 to 2019, and explored the differences between county-level and provincial-level or city-level results. It was observed that energy-related activities are the main source of GHG emissions in Anji and that economic development is the driving factor behind the increasing CO2 emissions. However, industrial transformation and upgradation coupled with the alternative use of clean energy limit the growth of GHG emissions. This study details the GHG emissions of county during the industrial transformation stage and provides corresponding policy recommendations for county governments.

A multi-scale framework for advancing national dairy sector GHG mitigation in Israel

Dairy production systems display a wide range of greenhouse gas (GHG) emission characteristics influenced by factors like geographical location, farm size, herd composition, milk yield, management practices, and existing infrastructure. Effective national GHG mitigation plans for the dairy industry should incorporate strategies that account for the diversity within this system. This paper aims to introduce a multi-scale framework to assess the GHG mitigation potential within the Israeli dairy system. It begins by analyzing the GHG intensity per unit of milk produced by a representative sample of 145 farms (20 % of the national dairy farms). It then extrapolates the data to the regional and national scales. The research reveals an average carbon footprint of 1.18 (ranging from 0.8 to 1.64) kg CO2e per kilogram of milk (FPCM) over the life cycle up to the farm gate. Upon scaling up, the study estimates the annual carbon footprint of the Israeli dairy industry at 1,777,800 t of CO2e. Consequently, this framework highlights areas with significant GHG emissions that require attention and opportunities for national mitigation based on the detailed characteristics of the studied systems.

Greenhouse gas production from an intermittently dosed cold-climate wastewater treatment wetland

This study explores the greenhouse gas (GHG) fluxes of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) from a two-stage, cold-climate vertical-flow treatment wetland (TW) treating ski area wastewater at 3 °C average water temperature. The system is designed like a modified Ludzack-Ettinger process with the first stage a partially saturated, denitrifying TW followed by an unsaturated nitrifying TW and recycle of nitrified effluent. An intermittent wastewater dosing scheme was established for both stages, with alternating carbon-rich wastewater and nitrate-rich recycle to the first stage. The system has demonstrated effective chemical oxygen demand (COD) and total inorganic nitrogen (TIN) removal in high-strength wastewater over seven years of winter operation. Following two closed-loop, intensive GHG winter sampling campaigns at the TW, the magnitude of N2O flux was 2.2 times higher for denitrification than nitrification. CH4 and N2O emissions were strongly correlated with hydraulic loading, whereas CO2 was correlated with surface temperature. GHG fluxes from each stage were related to both microbial activity and off-gassing of dissolved species during wastewater dosing, thus the time of sampling relative to dosing strongly influenced observed fluxes. These results suggest that estimates of GHG fluxes from TWs may be biased if mass transfer and mechanisms of wastewater application are not considered. Emission factors for N2O and CH4 were 0.27 % as kg-N2O-N/kg-TINremoved and 0.04 % kg-CH4-C/kg-CODremoved, respectively. The system had observed seasonal emissions of 600.5 kg CO2 equivalent of GHGs estimated over 130-days of operation. These results indicate a need for wastewater treatment processes to mitigate GHGs.

Tracking the change in Spanish greenhouse gas emissions through an LMDI decomposition model: A global and sectoral approach

The reduction of GHG emissions to reverse the greenhouse effect is one of the main challenges in this century. In this paper we pursue two objectives. First, we analyze the evolution of GHG emissions in Spain in 2008-2018, at both the global and sectoral levels, with the variation in emissions decomposed into a set of determining factors. Second, we propose several actions specifically oriented to more tightly controlling the level of emissions. Our results showed a remarkable reduction (18.44%) in GHG emissions, mainly due to the intensity effect, but also to the production-per-capita effect. We detected somewhat different patterns among the various sectors analyzed. While the intensity effect was the most influential one in the agricultural, transport, and others sectors, the production-per-capita effect was predominant in the case of industry. The carbonization effect was revealed as crucial in the commerce sector. The above findings highlight the importance of the energy efficiency measures taken in recent years in the Spanish economy, also pointing to the need to deepen those strategies and to propose new measures that entail greater efficiency in emissions. Additional efforts in areas like innovation, R&D, diffusion of more eco-friendly technologies, and a greater use of greener energies all prove to be essential reduction actions to fight the greenhouse effect.

The greenhouse gas emissions from meat sheep production contribute double of household consumption in a Eurasian meadow steppe

With the rapid development of the economy, household activities have emerged as an important source of greenhouse gas (GHG) emissions, making them a crucial focal point for research in the pursuit of sustainable development and carbon emission reduction. Hulunber, as a typical steppe region in eastern Eurasia, is representative of studying the GHG emissions from household ranches, which are the basic production units in this region. In this paper, based on survey data of 2018 and 2019, we quantified and assessed GHG emissions from household ranches by combining life cycle assessment (LCA) and structural equation modeling (SEM) approaches, with LCA to define household ranches system boundary and SEM to determine the key driving factors of emissions. The results showed that GHG emissions of meat sheep live weight was 23.54 kg CO2-eq/kg. The major contributor to household GHG emissions was enteric methane (55.23 %), followed by coal use (20.80 %) and manure management systems (9.16 %), and other contributing factors (14.81 %). The SEM results indicated that the GHG emissions from household ranches were derived primarily by economic level, while the economic level was significantly affected by income. This study also found a significant positive and linear correlation between household GHG emissions and the number of meat sheep (R2 = 0.89, P < 0.001). The GHG emissions from meat sheep production (67.52 %) were double times greater than household livelihood consumption (32.48 %). These findings emphasized the importance of reducing emissions from meat sheep production and adjusting the energy mix of household livelihood, contributing to the establishment of a low-carbon household livelihood operation.

Aging Increases Global Annual Food Greenhouse Gas Emissions up to 300 Million Tonnes by 2100

The dietary preferences of the elderly population exhibit distinct variations from the overall averages in most countries, gaining increasing significance due to aging demographics worldwide. These dietary preferences play a crucial role in shaping global food systems, which will result in changed environmental impacts in the future such as greenhouse gas (GHG) emissions. We present a quantitative evaluation of the influence of population aging on the changes in GHG emissions from global food systems. To achieve this, we developed regional dietary coefficients (DCs) of the elderly based on the Global Dietary Database (GDD). We then reconciled the GDD with the dataset from the Food and Agriculture Organization of the United Nations (FAO) to calculate the food GHG emissions of the average population in each of the countries. By applying the DCs, we estimated the national food GHG emissions and obtained the variations between the emissions from aged and average populations. We employed a modified version of the regional integrated model of climate and the economy model (RICE) to forecast the emission trends in different countries based on FAO and GDD data. This integrated approach allowed us to evaluate the dynamic relationships among aging demographics, food consumption patterns, and economic developments within regions. Our results indicate that the annual aging-embodied global food GHG emissions will reach 288 million tonnes of CO2 equivalent (Mt CO2e) by 2100. This estimation is crucial for policymakers, entrepreneurs, and researchers as it provides insights into a potential future environmental challenge and emphasizes the importance of sustainable food production and consumption strategies to GHG emission mitigations associated with aging dietary patterns.

An umbrella review of health co-benefits from actions to reduce greenhouse gas emissions

BACKGROUND

There have been many modelled studies of potential health co-benefits from actions to reduce greenhouse gas emissions, but so far there have been no large-scale attempts to compare the magnitude of health and climate effects across sectors, countries, and study designs.

METHODS

As part of the Pathfinder Initiative project an umbrella review of studies was done, and 26 previous reviews were identified with 57 primary studies included. Studies included in the review were required to have quantified changes in greenhouse gas emissions and health effects (or risk factors) from defined actions to reduce climate effects. Study data were extracted and harmonised by standardising impact measures per 100 000 of the national population (or urban population for city-level actions), averaging effects over a 1-year period and aggregating actions into their respective sectors by use of a predefined framework.

FINDINGS

From 200 mitigation actions, the majority were in the agriculture, forestry, and land use sector (103 actions [52%]), followed by the transport sector (43 actions [22%]). The largest effects on greenhouse gas emissions were seen from actions in the energy sector, and these actions also had substantial health co-benefits in lower middle-income countries, although benefits were smaller in high-income settings. The greatest health benefits were seen from actions to change diets and introduce clean cookstoves. The major pathways to health were through reduced air pollution, healthier diets, and increased physical activity from switching to active travel modes. Effect sizes tended to be larger from national modelling studies and smaller from localised or implemented actions.

INTERPRETATION

The potential co-benefits to health from actions to reduce climate change are large, but most evidence still comes from modelling studies and from high-income and middle-income countries. There are also major context-dependent differences in the magnitude of effects found, so actions need to be tailored to the local context and careful attention needs to be paid to potential trade-offs and spillover effects.

FUNDING

The Wellcome Trust and the Oak Foundation.

Cattle production strategies to deliver protein with less land and lower environmental impact

Global land resources are over-exploited and natural habitats are declining, often driven by expanding livestock production. In Ireland, pastureland for grazing cattle and sheep account for circa 60% of terrestrial land use. The agriculture, forestry and other land use sector (AFOLU) is responsible for 44% of national greenhouse gas (GHG) emissions. A new Grassland Animal response Model (GLAM) was developed to relate livestock-cohort grass and feed requirements to farm-grassland system areas, enhancing environmental assessment of prospective AFOLU configurations. Although land conversion targets are often well-defined, they tend to lack a clear definition of where land sparing can occur. Through analyses of 10 scenarios of milk and beef production and management strategies, we found that displacing beef cows with dairy cows can increase national protein output while sparing up to 0.75 million ha (18%) of grassland (albeit with a minor increase in overseas land requirement for additional concentrate feed). Reducing slaughter age, increasing exports of male dairy calves and increasing grassland use efficiency on beef farms each achieved between 0.19 and 0.32 million ha of land sparing. Sexed semen to achieve more favourable male-female birth ratios had a minor impact. GHG emissions, ammonia emissions and nutrient leaching were only reduced substantially when overall cattle numbers declined, confirming the need for cattle reductions to achieve environmental objectives. Nonetheless, application of GLAM shows potential for improved grass and cattle management to spare good quality land suitable for productive forestry and wetland restoration. This change is urgently needed to generate scalable carbon dioxide removals from the land sector in Ireland, and globally.

Healthcare in the era of climate change and the need for environmental sustainability

ABSTRACT

Climate change is an existential threat to humanity. While the healthcare sector must manage the health-related consequences of climate change, it is a significant contributor to greenhouse gas emissions, responsible for up to 4.6% of global emission, aggravating global warming. Within the hospital environment, the three largest contributors to greenhouse gas emissions are the operating theatre, intensive care unit and gastrointestinal endoscopy. Knowledge of the health-related burden of climate change and the potential transformative health benefits of climate action is important to all health professionals, as they play crucial roles in effecting change. This article summarises the available literature on the impact of healthcare on climate change and efforts in mitigation, focusing on the intrinsic differences and similarities across the operating theatre complex, intensive care unit and gastrointestinal endoscopy unit. It also discusses strategies to reduce carbon footprint.

Environmental Sustainability and MRI: Challenges, Opportunities, and a Call for Action

The environmental impact of magnetic resonance imaging (MRI) has recently come into focus. This includes its enormous demand for electricity compared to other imaging modalities and contamination of water bodies with anthropogenic gadolinium related to contrast administration. Given the pressing threat of climate change, addressing these challenges to improve the environmental sustainability of MRI is imperative. The purpose of this review is to discuss the challenges, opportunities, and the need for action to reduce the environmental impact of MRI and prepare for the effects of climate change. The approaches outlined are categorized as strategies to reduce greenhouse gas (GHG) emissions from MRI during production and use phases, approaches to reduce the environmental impact of MRI including the preservation of finite resources, and development of adaption plans to prepare for the impact of climate change. Co-benefits of these strategies are emphasized including lower GHG emission and reduced cost along with improved heath and patient satisfaction. Although MRI is energy-intensive, there are many steps that can be taken now to improve the environmental sustainability of MRI and prepare for the effects of climate change. On-going research, technical development, and collaboration with industry partners are needed to achieve further reductions in MRI-related GHG emissions and to decrease the reliance on finite resources. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 6.

Uncertainty analysis of greenhouse gas emissions of monorail transit during the construction

This paper examines the uncertainty of greenhouse gas (GHG) emissions during monorail construction. Firstly, a deterministic analysis is conducted. Subsequently, the obtained data are evaluated using the data quality indicator (DQI), and a Markov chain Monte Carlo (MCMC) simulation method is employed to assume different parameter distributions. The results of the deterministic calculation indicate that the calculated emissions per unit area of the station amount to 1.97 ton CO2e/m2, while the calculated emissions per unit section length reach 7.55 ton CO2e/m2. To simulate parameter distribution, we utilize a Beta distribution with good shape applicability. Furthermore, we establish scenarios involving system boundary reduction, low-emission factors, and reduced material and energy inputs in order to analyze scenario uncertainties. Regarding model uncertainty, this paper assumes that the material and energy quantity data conform to the normal, log-normal, uniform, and triangular distributions, respectively, subsequently analyzing the uncertainty distributions. This paper analyzes the GHG emission uncertainty evaluation of 16 monorail stations and sections during the construction period, which is divided into parameter, scenario, and model uncertainty. We provide a concrete framework for studying uncertainties related to GHG emissions at stations and sections during the monorail construction period. The scenario analysis results will help to make decisions about the choice of parameters, system boundaries, and other settings. It provides new guidance for emission reduction policies, such as reducing the use of steel-related products or using alternative environmentally friendly materials, considering emission reduction factors more comprehensively and setting emission reduction factors according to uniform distribution principle as far as possible.

The carbon footprint and wastage of intravitreal injections

PURPOSE

The healthcare system emits greenhouse gas emissions and produces waste that in turn threatens the health of populations. The objective of our study was to measure the ecological threat related to intravitreal injections.

METHODS

Emissions were separated into scope 2 corresponding to Heating, Ventilation and Air Conditioning (HVAC) of the building, and scope 3 corresponding to travels (patients and staff), and life cycle assessment (LCA) of medical devices (MD) and pharmaceutics. Greenhouse gas (GHG) emissions and waste for a single injection were first measured through a waste audit, and secondly anticipated theoretically with a calculator.

RESULTS

The average GHG emissions and waste measured were 277kgCO2eq/IVI and 0.5kg/IVI, respectively. Pharmaceuticals were responsible for 97% of total emissions. Emissions unrelated to pharmaceuticals counted for 8.4kgCO2eq/IVI. GHG emissions and waste estimated with the calculator were 276kgCO2eq/IVI and 0.5kg/IVI, respectively, showing that the calculator was accurate.

CONCLUSION

Our study provides a puzzle piece to carbon footprint and waste assessment in the field of ophthalmology. It may help provide concrete data for future green vs. vision discussions.

Greenhouse gas emissions from on-site sanitation systems: A systematic review and meta-analysis of emission rates, formation pathways and influencing factors

Onsite sanitation systems (OSS) are significant sources of greenhouse gases (GHG) including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). While a handful of studies have been conducted on GHG emissions from OSS, systematic evaluation of literature on this subject is limited. Our systematic review and meta-analysis provides state-of-the- art information on GHG emissions from OSS and identifies novel areas for investigation. The paper analyzes GHG emission rates from different OSS, the influence of various design, operational, and environmental factors on emission rates and proffers mitigation measures. Following the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines, we identified 16 articles which quantified GHG emissions from OSS. Septic tanks emit substantial amounts of CO2 and CH4 ranging from 1.74 to 398.30 g CO2/cap/day and 0.06-110.13 g CH4/cap/day, respectively, but have low N2O emissions (0.01-0.06 g N₂O/cap/day). CH4 emissions from pit latrines range from 0.77 to 20.30 g CH4/cap/day N2O emissions range from 0.76 to 1.20 gN2O/cap/day. We observed statistically significant correlations (p < 0.05) between temperature, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, storage period, and GHG emissions from OSS. However, no significant correlation (p > 0.05) was observed between soil volumetric water content and CO2 emissions. CH4 emissions (expressed as CO2 equivalents) from OSS estimated following Intergovernmental Panel for Climate Change (IPCC) guidelines were found to be seven times lower (90.99 g CO2e/cap/day) than in-situ field emission measurements (704.7 g CO2e/cap/day), implying that relying solely on IPCC guidelines may lead to underestimation of GHG emission from OSS. Our findings underscore the importance of considering local contexts and environmental factors when estimating GHG emissions from OSS. Plausible mitigation measures for GHG emissions from OSS include converting waste to biogas in anaerobic systems (e.g. biogas), applying biochar, and implementing mitigation policies that equally address inequalities in sanitation service access. Future research on GHG from OSS should focus on in-situ measurements of GHGs from pit latrines and other common OSS in developing countries, understanding the fate and transport of dissolved organics like CH4 in OSS effluents and impacts of microbial communities in OSS on GHG emissions. Addressing these gaps will enable more holistic and effective management of GHG emissions from OSS.

Carbon reduction trade-off between pretreatment and anaerobic digestion: A field study of an industrial-scale biogas plant

With the implementation of municipal solid waste source segregation, the enormous sorted biogenic waste has become an issue that needs to be seriously considered. Anaerobic digestion, which can produce biogas and extract floating oil for biodiesel production, is the most prevalent treatment in China for waste management and greenhouse gas (GHG) emissions reduction, in accordance with Sustainable Development Goal 13 of the United Nations. Herein, a large-scale biogas plant with a capacity of 1000 tonnes of biogenic waste (400 tonnes of restaurant biogenic waste and 600 tonnes of kitchen biogenic waste) per day was investigated onsite using material flow analysis, and the parts of the biogas plant were thoroughly analyzed, especially the pretreatment system for biogenic waste impurity removal and homogenization. The results indicated that the loss of the total biodegradable organic matter was 41.8% (w/w) of daily feedstock and the loss of biogas potential was 18.8% (v/v) of daily feedstock. Life cycle assessment revealed that the 100-year GHG emissions were -61.2 kgCO2-eq per tonne biogenic waste. According to the sensitivity analysis, pretreatment efficiency, including biodegradable organic matter recovery and floating oil extraction, considerably affected carbon reduction potential. However, when the pretreatment efficiency deteriorated, GHG benefits of waste source segregation and the subsequent biogenic waste anaerobic digestion would be reduced.

What is the environmental impact of a blood transfusion? A life cycle assessment of transfusion services across England

BACKGROUND

Healthcare activities significantly contribute to greenhouse gas (GHG) emissions. Blood transfusions require complex, interlinked processes to collect, manufacture, and supply. Their contribution to healthcare emissions and avenues for mitigation is unknown.

STUDY DESIGN AND METHODS

We performed a life cycle assessment (LCA) for red blood cell (RBC) transfusions across England where 1.36 million units are transfused annually. We defined the process flow with seven categories: donation, transportation, manufacturing, testing, stockholding, hospital transfusion, and disposal. We used direct measurements, manufacturer data, bioengineering databases, and surveys to assess electrical power usage, embodied carbon in disposable materials and reagents, and direct emissions through transportation, refrigerant leakage, and disposal.

RESULTS

The central estimate of carbon footprint per unit of RBC transfused was 7.56 kg CO2 equivalent (CO2eq). The largest contribution was from transportation (2.8 kg CO2eq, 36% of total). The second largest was from hospital transfusion processes (1.9 kg CO2eq, 26%), driven mostly by refrigeration. The third largest was donation (1.3 kg CO2eq, 17%) due to the plastic blood packs. Total emissions from RBC transfusion are ~10.3 million kg CO2eq/year.

DISCUSSION

This is the first study to estimate GHG emissions attributable to RBC transfusion, quantifying the contributions of each stage of the process. Primary areas for mitigation may include electric vehicles for the blood service fleet, improving the energy efficiency of refrigeration, using renewable sources of electricity, changing the plastic of blood packs, and using methods of disposal other than incineration.

Subsidizing Grid-Based Electrolytic Hydrogen Will Increase Greenhouse Gas Emissions in Coal Dominated Power Systems

Clean hydrogen has the potential to serve as an energy carrier and feedstock in decarbonizing energy systems, especially in "hard-to-abate" sectors. Although many countries have implemented policies to promote electrolytic hydrogen development, the impact of these measures on costs of production and greenhouse gas emissions remains unclear. Our study conducts an integrated analysis of provincial levelized costs and life cycle greenhouse gas emissions for all hydrogen production types in China. We find that subsidies are critical to accelerate low carbon electrolytic hydrogen development. Subsidies on renewable-based hydrogen provide cost-effective carbon dioxide equivalent (CO2e) emission reductions. However, subsidies on grid-based hydrogen increase CO2e emissions even compared with coal-based hydrogen because grid electricity in China still relies heavily on coal power and likely will beyond 2030. In fact, CO2e emissions from grid-based hydrogen may increase further if China continues to approve new coal power plants. The levelized costs of renewable energy-based electrolytic hydrogen vary among provinces. Transporting renewable-based hydrogen through pipelines from low- to high-cost production regions reduces the national average levelized cost of renewables-based hydrogen but may increase the risk of hydrogen leakage and the resulting indirect warming effects. Our findings emphasize that policy and economic support for nonfossil electrolytic hydrogen is critical to avoid an increase in CO2e emissions as hydrogen use rises during a clean energy transition.

Effect of slaughter age on environmental efficiency on beef cattle in marginal area including soil carbon sequestration: A case of study in Italian Alpine area

The production of beef carries significant environmental repercussions on a worldwide level. Considering that the production of beef in Alpine mountainous regions, such as South Tyrol (Italy), constitutes a modest yet progressively growing segment within the local agricultural sector focus must be put on minimizing the environmental impact of producing one kilogram of meat, while also accounting for the carbon sequestered by Alpine pastures in such marginal areas. To this end 20 beef farms distributed in the South Tyrolean region (Italy) were divided based on the age at slaughter of the beef cattle: 10 farms with a slaughter age of 12 months (SA12) and 10 farms with a slaughter age of 24 months (SA24). Live cycle assessment (LCA) approach was used, and the impact was estimated using two functional units (FU): 1 kg of live weight (LW) and 1 kg of carcass weight (CW). Global warming potential (GWP100, kg CO2-eq), acidification potential (AP, g SO2-eq), and eutrophication potential (EP, g PO4-eq) were investigated. Furthermore, within the account, the carbon sequestered by pastures and permanent grassland has been included for estimated the overall carbon footprint. In terms of GWP100, the SA12 system proved to be significantly lower for both two functional units under studies, with reductions of 8.5 % and 7.4 % in terms of LW and CW, respectively, compared to the SA24 system, specifically, the SA12 system showed an environmental impact in terms of GWP100 of 19.5 ± 1.1 kg CO2-eq/kg LW, which was significantly lower than the SA24 system that exhibited a value of 22.9 ± 1.1 kg CO2-eq/kg LW (P < 0.05). When accounting for the carbon sequestered within the system, the observed values in terms of GWP100 are significantly lower for SA12 compared to SA24, 17.6 ± 1.5 vs. 20.9 ± 1.5 kg CO2-eq/Kg LW (P < 0.05), and 29.2 ± 2.5 vs. 38.7 ± 2.5 kg CO2-eq/Kg CW (P < 0.01). These differences are due to less purchase of concentrated feed and greater use of natural resources such as pastures and permanent grasslands. The research indicated that the production of beef in the Alpine region of South Tyrol predominantly occurs within extensive parameters, leading to a satisfactory environmental profile, also including the C sequestration.

Global production patterns: Understanding the relationship between greenhouse gas emissions, agriculture greening and climate variability

Climate change due to increased greenhouse gas emissions (GHG) in the atmosphere has been consistently observed since the mid-20th century. The profound influence of global climate change on greenhouse gas (GHG) emissions, encompassing carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), has established a vital feedback loop that contributes to further climate change. This intricate relationship necessitates a comprehensive understanding of the underlying feedback mechanisms. By examining the interactions between global climate change, soil, and GHG emissions, we can elucidate the complexities of CO2, CH4, and N2O dynamics and their implications. In this study, we evaluate the global climate change relationship with GHG globally in 246 countries. We find a robust positive association between climate and GHG emissions. By 2100, GHG emissions will increase in all G7 countries and China while decreasing in the United Kingdom based on current economic growth policies, resulting in a net global increase, suggesting that climate-driven increase in GHG and climate variations impact crop production loss due to soil impacts and not provide climate adaptation. The study highlights the diverse strategies employed by G7 countries in reducing GHG emissions, with France leveraging nuclear power, Germany focusing on renewables, and Italy targeting its industrial and transportation sectors. The UK and Japan are making significant progress in emission reduction through renewable energy, while the US and Canada face challenges due to their industrial activities and reliance on fossil fuels.

Navigating Sustainability through Greenhouse Gas Emission Inventory: ESG Practices and Energy Shift in Bangladesh's Textile and Readymade Garment Industries

As the world's demand for textiles and clothing rapidly increases, this industry's greenhouse gas (GHG) emissions are becoming a major environmental concern. Bangladesh, a key player in the global textile supply chain and one of the top producers, contributes significantly to these emissions. However, accessible data on activity and GHG emissions, crucial for researchers, the private sector, and policymakers in decision-making, is scarce. To address this gap, this study combines a detailed field survey with expert interviews to establish a comprehensive emission inventory. This inventory aims to identify hotspots and facilitate the adoption of effective mitigation strategies. Focusing on a prominent industrial zone's textile and readymade garments (RMG) industries, the research employs a mix of top-down and bottom-up approaches and follows the IPCC guidelines to develop a GHG emission inventory for 2022. The study evaluates various emission sources, including scope 1 (onsite fuel combustions), scope 2 (grid electricity usage), and scope 3 (waste and wastewater treatment). In the total emissions (6043.5 Gg CO2eq.), textile and RMG industries contribute 67.8% and 32.2%, respectively, with scope 1 emissions dominating at 85%. Notably, scope 2 emissions exhibit significant uncertainty (-10.4% to +11.9%), largely due to variations in national grid emission factors. This study forecasts GHG emissions until 2030, considering current trends (26 thousand Gg CO2 eq.). It also explores various energy mix scenarios, factoring in the depletion of existing natural gas reserves (ranging from 8 thousand to 33 thousand Gg CO2 eq.). This study delves into the impact of the Environmental, Social, and Governance (ESG) system on industries' GHG emissions. Besides improving worldwide emission databases and identifying hotspots, this research aims to promote a sustainable transition in both Bangladesh and other developing textile manufacturing nations across the globe.

Deforestation and greenhouse gas emissions could arise when replacing palm oil with other vegetable oils

Oil crops are among the main drivers of global land use changes. Palm oil is possibly the most criticized, as a driver of primary tropical forests loss. This has generated two different reactions in its use in various sectors (e.g., food, feed, biodiesel, surfactant applications, etc.): from one side there is a growing claim for deforestation-free palm oil, whereas on the other side the attention raised towards other vegetable oils as possible substitutes, such as soybean, rapeseed and sunflower oil. We assess potential land use changes and consequent greenhouse gas (GHG) emissions for switching from palm oil to other oils and compare this solution to deforestation-free palm oils. We consider three scenarios of 25 %, 50 % and 100 % palm oil replacement in the eight major oil crop producing countries. Total GHG emissions account for anthropogenic emissions generated along the life cycle of the field production process and potential forest carbon stock losses from land use change for oil crops expansion. Replacing palm oil with other oils would have a worthless effect in terms of global emissions reduction since GHG emissions remain approximatively stable across the three scenarios, whereas it would produce a deforestation increase of 28.2 to 51.9 Mha worldwide (or 7 to 21.5 Mha if excluding the unlikely deforestation in USA, Russia, Ukraine and the offset deforestation in China, India). Conversely, if the global palm oil production becomes deforestation-free, its GHG emissions would be reduced by 92 %, switching from the current 371 to 29 Mt CO2eq per year. Although highlighting the historical unsustainability of oil palm plantations, results show that replacing them with other oil crops almost never represents a more sustainable solution, thus potentially questioning sustainability claims of palm oil free products with respect to deforestation-free palm oil.

Unveiling the greenhouse gas emissions of drinking water treatment plant throughout the construction and operation stages based on life cycle assessment

The carbon peaking and carbon neutrality targets proposed by the Chinese government have initiated a green transformation that is full of challenges and opportunities and endowed sustainable development strategy for combating global warming issue. It is essential to execute comprehensive identification and carbon reduction measures across all industries that produce greenhouse gas (GHG) emissions. Water supply system, as an energy-intensive sector, plays a crucial role in GHG reduction. This work conducted a life cycle assessment (LCA) to account the GHG emissions associated with the construction and operation phases of the drinking water treatment plant (DWTP). During the construction phase, the total GHG emissions were 19,525.762 t CO2-eq, with concrete work and rebar project being the dominant contributors (87.712%). The promotion of renewable or recyclable green building materials and low-carbon construction methods, such as the utilization of prefabricated components and on-site assembly, holds significant importance in reducing GHG emissions during the construction phase of DWTP. Regarding the operation stage, the DWTP possessed an average annual GHG emission of 37,660.160 t CO2-eq and an average GHG intensity of 0.202 kg CO2-eq/m3. Most emissions were attributed to electricity consumption (67.388%), chemicals utilization (12.893%), and heat consumption (10.414%). By increasing the use of clean energy and implementing strict control measures in the water supply pumps, energy consumption and GHG emissions can be effectively reduced. This study offers valuable insights into the mapping of GHG emissions in the DWTP, facilitating the identification of key areas for targeted implementation of energy-saving and carbon-reducing measures.

Low-carbon city construction, spatial spillovers and greenhouse gas emission performance: Evidence from Chinese cities

Low-carbon cities (LCC) are conducive to low-carbon development and reshaping the urban economic growth model. However, it is still unknown whether it has a synergistic mitigation effect on other greenhouse gases (GHGs). In this study, a dataset comprising 283 Chinese cities spanning the period 2003 to 2019 is chosen. We employ spatial difference-in-difference (SDID) modeling to investigate both the impacts and mechanisms of LCC on GHG emissions performance. The results show that (1) LCC notably lowers local GHG emissions, enhances emission efficiency, and improves GHG emissions performance in neighboring cities within a 1000 km radius. (2) LCC indirectly enhances the GHG emissions performance of local and neighboring cities through energy intensity and green technology innovation. Notably, LCC boosts the local GHG emissions performance by industrial structure upgrading and resource allocation but harms the positive spillover effects on nearby cities due to the siphoning effect. (3) The effect and spatial impact of LCC on GHG emission performance is notably pronounced in eastern cities, non-resource cities, and key environmental protection areas. The results of the study will further promote the development of LCC and provide an important decision-making reference for urban low-carbon sustainability.

A multi-factor combination prediction model of carbon emissions based on improved CEEMDAN

As the global greenhouse effect intensifies, carbon emissions are gradually becoming a hot topic of discussion. Accurate carbon emissions prediction is an important foundation to realize carbon neutrality and peak carbon dioxide emissions. To accurately predict carbon emissions, a multi-factor combination prediction model based on improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN), bidirectional long short-term memory optimized by lemurs optimizer (LOBiLSTM) and least squares support vector machine optimized by lemurs optimizer (LOLSSVM), named ICEEMDAN-LOBiLSTM-LOLSSVM, is proposed. Firstly, the influencing factors of carbon emissions are selected by Spearman correlation coefficient, and carbon emissions are decomposed into intrinsic mode functions (IMFs) by ICEEMDAN. Secondly, the influencing factors and IMFs are input into LOBiLSTM and LOLSSVM respectively for prediction. Then, the point prediction results are obtained by weighting the prediction results of LOBiLSTM and LOLSSVM. Finally, probability density function of point prediction error is calculated by kernel density estimation, and the interval prediction results are calculated according to different confidence intervals. Carbon emissions of China and Germany are selected to verify the superiority of ICEEMDAN-LOBiLSTM-LOLSSVM. The experiment shows that RMSE, MAE, MAPE, and R2 of the proposed model are 0.4468, 0.3612, 0.0120, and 0.9839 respectively for China, which is the best among the nine models, as well as for Germany.

The race between global economic growth and carbon emissions: based on a comparative study of developed and developing countries

In recent years, there has been a persistent intensification of the global greenhouse effect. Balancing carbon emission reduction with economic growth poses an unprecedented global challenge. To better comprehend the relationship between economic growth and carbon emissions, this study first utilized the Tapio decoupling index to compare the decoupling relationship (the USA, Japan, and Germany) and three developing countries (China, India, and Russia) from 2000-2020. Additionally, the logarithmic mean Divisia index (LMDI) method was employed to investigate the factors influencing changes in carbon emissions. Our findings indicate that (1) the USA and Germany basically achieved strong decoupling; China, India, and Russia mainly showed weak decoupling; and Japan showed recessive decoupling. (2) Economic growth predominantly contributed to increased carbon emissions, with a lesser impact from population growth. A significant reduction in energy intensity restrained carbon emissions growth, as did energy structure replacement in most countries, excluding Japan. Based on this, a decoupling effort index was formulated. It has shown that the decoupling efforts made by developing countries are weaker than those of developed countries, primarily attributed to a lesser degree of decoupling between energy intensity and structure. This paper offers valuable insights for developing countries undergoing a low-carbon economic transformation. They should counterbalance carbon emission escalation resulting from economic growth through technological and energy structure improvements.

Spatial-temporal characteristics and driving factors' contribution and evolution of agricultural non-CO2 greenhouse gas emissions in China: 1995-2021

Comprehending the spatial-temporal characteristics, contributions, and evolution of driving factors in agricultural non-CO2 greenhouse gas (GHG) emissions at a macro level is pivotal in pursuing temperature control objectives and achieving China's strategic goals related to carbon peak and carbon neutrality. This study employs the Intergovernmental Panel on Climate Change (IPCC) carbon emissions coefficient method to comprehensively evaluate agricultural non-CO2 GHG emissions at the provincial level. Subsequently, the contributions and spatial-temporal evolution of six driving factors derived from the Kaya identity were quantitatively explored using the Logarithmic Mean Divisia Index (LMDI) and Geographical and Temporal Weighted Regression (GTWR) methods. The results revealed that the distribution of agricultural non-CO2 GHG emissions is shifting from the central provinces to the northwest regions. Moreover, the dominant driving factors of agricultural non-CO2 GHG emissions were primarily economic factor (EDL) with positive impact (cumulative promotion is 2939.61 million metric tons (Mt)), alongside agricultural production efficiency factor (EI) with negative impact (cumulative reduction is 2208.98 Mt). Influence of EDL diminished in the eastern coastal regions but significantly impacted underdeveloped regions such as the northwest and southwest. In the eastern coastal regions, EI gradually became the absolute dominant driver, demonstrating a rapid reduction effect. Additionally, a declining birth rate and rural-to-urban population migration have significantly amplified the driving effects of the population factor (RP) at a national scale. These findings, in conjunction with the disparities in geographic and socioeconomic development among provinces, can serve as a guiding framework for the development of a region-specific roadmap aimed at reducing agricultural non-CO2 GHG emissions.

Inhalational volatile anaesthetic agents: the atmospheric scientists' viewpoint

All sectors of society must reduce their carbon footprint to mitigate climate change, and the healthcare community is no exception. This narrative review focuses on the environmental concerns associated with the emissions of volatile anaesthetic agents, some of which are potent greenhouse gases. This review provides an understanding of the global warming potential metric, as well as the concepts of atmospheric lifetime and radiative efficiency. The state of knowledge of the environmental impact and possible climate forcing of emitted volatile anaesthetic agents are reviewed. Additionally, the review discusses how climate metrics can guide mitigation strategies to reduce emissions and suggests present and future options for mitigating the climate impact.

Spatial and temporal evolution and drivers of GHG emissions from urban domestic wastewater treatment in China: a review at the provincial level

To mitigate greenhouse gas (GHG) emissions from the wastewater treatment industry, it is crucial to explore GHG emission patterns and propose useful measures. In this study, we use the Kaya model and LMDI decomposition method to analyze the changes in GHG emissions from urban domestic wastewater treatment at the provincial level and further explore the distribution characteristics and driving factors of urban domestic wastewater treatment GHG emissions across various years and regions. The results indicate the following: (1) In the temporal dimension, urban domestic wastewater treatment GHG emissions are increasing, from 21.0 MtCO2 in 2011 to 27.1 MtCO2 in 2020, with an average annual growth rate of 2.88%. The spatial distribution is high in the southeast and low in the northwest. There is variability in the spatial evolution trend of GHG emissions by province, with the growth rate becoming slower or even negative in Jiangsu, Zhejiang, and North China, while the average annual growth rate exceeds 25% in Inner Mongolia and Xinjiang. (2) According to the decomposition results of driving factors, economic scale is the dominant positive driver, and the positive contributions of TI and the population effect are limited. The sludge disposal structure is the main negative driver, and the EEI and technology have restricted negative contributions. (3) Based on the decomposition results, for major coastal GHG emitters, such as Guangdong and Shandong, it is necessary to invest capital and technology to continuously upgrade the wastewater treatment process and reduce non-CO2 emissions. Along with adopting circular economy schemes, local governments in the northwestern region should transform the traditional sludge disposal structure and optimize the power supply structure to increase carbon offset and reduce CO2 emissions. The findings suggest a low-carbon transformation path to support the industry's dual carbon goals.

Interventions to increase circularity and reduce environmental impacts in food systems

Applying specific circularity interventions to the food system may have environmental benefits. Using an iterative linear food system optimisation model (FOODSOM), we assess how changes in human diets, imports and exports, and the utilisation of waste streams impact land use and greenhouse gas emissions (GHG). After including these circularity principles, land use and GHG emissions were on average 40% and 68% lower than in the current food system, primarily driven by a reduction in production volumes and a shift towards feeding the domestic population. Shifting from the current diet to a circular diet decreased land use with 43% and GHG emissions with 52%. Allowing up to half of each nutrient in the human diet to be imported, while balancing imports with equal exports in terms of nitrogen, phosphorus and potassium, also decreased land use (up to 34%) and GHG emissions (up to 26%) compared to no imported food. Our findings show that circularity interventions should not be implemented mutually exclusively; by combining a circular diet with imported food and fully utilising waste streams, the lowest land use and GHG emissions can be realised.

Reassessing the greenhouse effect of biogenic carbon emissions in constructed wetlands

Biogenic carbon emissions, including carbon dioxide (CO2) and methane (CH4), have emerged as a major concern during organic pollutant degradation within constructed wetlands (CWs). Since these organic compounds primarily originate from the photosynthetic fixation of atmospheric CO2, it potentially introduces uncertainty when assessing the greenhouse effect of biogenic carbon emissions in CWs based on direct field observations. To objectively assessing this effect, this study proposed a new strategy by quantifying CO2-equivalent (CO2-eq) changes as carbon passes through CWs and tested it in various types of CWs based on 64 literature records. The findings reveal that CWs can contribute to CO2-eq additions, yet are only responsible for 15.6% derived from direct field observations. The type of CWs plays a crucial role in these CO2-eq additions, with vertical flow CWs causing the lowest levels (6.8%), followed by surface flow CWs (14.2%). In contrast, horizontal flow CWs are associated with the strongest CO2-eq addition (25.7%). The findings provide new insights for the objective assessment of the greenhouse effect of biogenic carbon emissions in CWs, which will be beneficial for future life cycle assessment.

In search for climate neutrality in ice hockey: A case of carbon footprint reduction in a Finnish professional team

Mitigation actions in all sectors of society, including sports, to limit global warming have become an increasingly hot topic in public discussions and sports management. However, so far, there has been a lack of understanding and practical examples of how these organizations, especially in team sports, can holistically assess and reduce their climate impacts to achieve carbon neutrality. This paper presents a carbon footprint assessment, implemented actions for GHG emission reduction, and offers the example of a professional Finnish ice hockey team that achieved carbon neutrality. The study is based on a life cycle assessment method. The Results show that the team's carbon footprint was reduced from 350 tCO2eq by more than 50% between seasons 2018-2019 and 2021-2022 in the assessed categories. The most GHG emission reductions were achieved in the team's and spectators' mobility and ice hall energy consumption. Furthermore, the team compensated for their remaining emissions to achieve carbon neutrality. Multiple possibilities for further GHG emission reductions were recognized. The majority of the GHG emissions were linked to the Scope 3 category, indicating that co-operation with partners and stakeholders was a key to success in attaining carbon neutrality. This paper also discusses the possible limitations and challenges that sport organizations face in assessing climate impacts and reducing GHG emissions, as well as the prospects of overcoming them. Since there are many opportunities for sports to contribute to climate change mitigation, relevant targets and actions to reduce GHG emissions should be integrated into all sport organizations' management.

Addressing Climate Health: A Practical Guide to Quantifying and Reducing Health Care-Associated Emissions

OBJECTIVE

The objective was to quantify annual greenhouse gas emissions from a surgical specialty hospital and identify high-yield areas to reduce emissions associated with patient care.

STUDY DESIGN

Pre-post study, greenhouse gas inventory.

SETTING

Specialty hospital.

METHODS

A scope 1 and scope 2 greenhouse gas inventory of the Massachusetts Eye and Ear main campus for calendar years (CY) 2020, 2021, and 2022 was performed by assessing emissions attributable to on-site sources (scope 1) and purchased electricity and steam (scope 2). The associated carbon dioxide equivalent was then calculated using known global warming potentials and emission factors.

RESULTS

The major contributors to scope 1 and scope 2 emissions at our institution for CY 2020 to 2022 were waste anesthetic gases and purchased steam. These results were reviewed with hospital leadership and a plan was developed to reduce these emissions. Emission monitoring is ongoing to assess the efficacy of these interventions.

CONCLUSION

Measuring scope 1 and scope 2 emissions at the facility level allows health care facilities to develop institution-specific interventions and compare data across health care organizations. Surgeons can lead on health care system sustainability by collaborating with clinical and nonclinical staff to measure emissions, developing targeted emissions-reduction interventions, and tracking progress with yearly assessments.

Challenges to decarbonizing medication prescribing and use practices: A call to action

Climate change undeniably impacts the social and environmental determinants of one's health. The healthcare sector, encompassing medications and the pharmaceutical industry supply chain, accounts for a significant portion of global health care contributions to greenhouse gas (GHG) and waste production. Despite these realities, healthcare professionals - physicians, pharmacists, nurses, and others - may be unaware of GHG emissions and the long-term environmental effects of the medications they prescribe, dispense, and administer daily. In this commentary, we identify existing challenges and explore potential strategies to recognize and reduce the climate change impacts associated with medication use.

Crop byproducts supplemented in livestock feeds reduced greenhouse gas emissions

Crop byproducts can be supplemented in livestock feeds to improve the utilization of resources and reduce greenhouse gas (GHG) emissions. We explored the mitigation potential of GHG emissions by supplementing crop byproducts in feeds based on a typical intensive dairy farm in China. Results showed that GHG emissions associated with production of forage were significantly decreased by 25.60 % when no GHG emissions were allocated to crop byproducts, and enteric methane emission was significantly decreased by 13.46 % on the basis of CO2 eq, g/kg fat and protein corrected milk. The supplementation did not affect lactation performance, rumen microbiota and microbial enzymes at the gene level. Metabolomics analysis revealed changes in amino acid catabolism of rumen fluid, which were probably responsible for more propionate production. In conclusion, supplementing crop byproducts in feeds can be a potential strategy to reduce GHG emissions of livestock.

Carbon footprint of hospital laundry: a life-cycle assessment

OBJECTIVES

To assess greenhouse gas (GHG) emissions from a regional hospital laundry unit, and model ways in which these can be reduced.

DESIGN

A cradle to grave process-based attributional life-cycle assessment.

SETTING

A large hospital laundry unit supplying hospitals in Southwest England.

POPULATION

All laundry processed through the unit in 2020-21 and 2021-22 financial years.

PRIMARY OUTCOME MEASURE

The mean carbon footprint of processing one laundry item, expressed as in terms of the global warming potential over 100 years, as carbon dioxide equivalents (CO2e).

RESULTS

Average annual laundry unit GHG emissions were 2947 t CO2e. Average GHG emissions were 0.225 kg CO2e per item-use and 0.5080 kg CO2e/kg of laundry. Natural gas use contributed 75.7% of on-site GHG emissions. Boiler electrification using national grid electricity for 2020-2022 would have increased GHG emissions by 9.1%, however by 2030 this would reduce annual emissions by 31.9% based on the national grid decarbonisation trend. Per-item transport-related GHG emissions reduce substantially when heavy goods vehicles are filled at ≥50% payload capacity. Single-use laundry item alternatives cause significantly higher per-use GHG emissions, even if reusable laundry were transported long distances and incinerated at the end of its lifetime.

CONCLUSIONS

The laundry unit has a large carbon footprint, however the per-item GHG emissions are modest and significantly lower than using single-use alternatives. Future electrification of boilers and optimal delivery vehicle loading can reduce the GHG emissions per laundry item.

Wastewater treatment, energy consumption, and greenhouse gas emissions: An operational approach to comparing Barcelona and Mexico City

This study delves into the critical nexus between wastewater treatment, energy consumption, and greenhouse gas emissions. Wastewater treatment is a linchpin of sustainable development, yet its energy-intensive processes contribute significantly to greenhouse gas emissions. The research focuses on wastewater treatment plants (WWTPs) in Mexico City (CDMX) and the Metropolitan Area of Barcelona (AMB), exploring the disparities between a developed country and a developing country. The study examines how factors such as water treatment technologies and electricity sources influence carbon emissions. The AMB exhibits superior performance by treating all wastewater, cogenerating energy from the biomass contained in the wastewater and generating 10% fewer emissions, in stark contrast to CDMX, which does not capture the CH4 produced during water treatment, on top of only treating the water of 14% of the city's agglomeration. It underscores the critical implications of WWTP efficiency on climate change and progress toward UN Sustainable Development Goals. Given the limited attention to the Global South, this research serves as a vital contribution to the discourse on sustainability and development.

Comparative life cycle assessment of sewage sludge treatment in Wuhan, China: Sustainability evaluation and potential implications

Owing to the relentless growth of sewage sludge production, achieving low-carbon development in sewage sludge treatment and disposal (STD) is becoming increasingly challenging and unpredictable. However, the STD varied spatially, and city-specific analysis is deemed necessary for sustainable evaluation. Therefore, a lifecycle-based greenhouse gas (GHG), energy, and economic analysis were conducted by considering six local STD alternatives in Wuhan City, China, as a case study. The findings indicated anaerobic digestion combined with digestate utilization for urban greening (ADL) and incineration in existing power plants (INCP) exhibited the least GHG emissions at 34.073 kg CO2 eq/FU and 644.128 kg CO2 eq/FU, while INCP generated the most energy at -2594 kW.h/FU. The economic evaluation revealed that ADL and INCP were more beneficial without accounting for land acquisition. Scenario analysis showed that the energy recovery from ADL and INCP is significantly influenced by the hydrolysis yielding rate and sludge organic content. Perturbation sensitivity indicates that regional emission factor of electricity and electricity fee highly influence the overall GHG emission and cost. The results of this study could assist policymakers in identifying viable solutions to the cities experiencing the same sludge treatment burdens.

Reduction of cost and emissions by using recycling and waste management system

In order to evaluate the level of sustainability of an integrated waste management system (IWMS), it is necessary to analyze the impact criteria. Therefore, the purpose of this study is to provide a model for IWMS optimization with the two goals of minimizing the cost and the emission of greenhouse gases of the entire system. Environmental and health problems caused by the lack of proper waste management include the increase in disease, increase in stray animals, pollution of air, water, land, etc. Therefore, it is very important to identify the indicators and improve the efficiency of the waste management system. In the present research, with descriptive-analytical approach, it has been tried to clarify and evaluate the effective indicators in two dimensions of production-segregation and collection-transportation, and find ways to improve the efficiency of the system. In this article, five waste management systems including, incineration, landfill without gas extraction system, plasma incineration, recycling and aerobic decomposition are introduced and their performance in energy production and emission reduction are compared. The results of the evaluation of the basic waste management system (b) show that the amount of pollution is equivalent to 850 kg CO2 per ton of waste. While the amount of emission in the fifth comprehensive management system is reduced to 450 kg CO2 per ton of waste. According to the results obtained in this study, in all the management systems presented, the process of burying waste in sanitary landfills has the greatest effect in increasing pollution. This means that the pollution caused by burying the waste in the sanitary landfill will be reduced with the construction of the gas extraction system and the plasma method and use in electricity production. Despite the increase in initial costs, using the right technology and using the right waste system based on the type of waste and waste recycling has an effect on the efficiency of the system.

Greenhouse gas emission inventory of drinking water treatment plants and case studies in China

The Chinese government claimed to reach carbon dioxide emissions peaking by 2030 and achieve carbon neutralization by 2060. In this context, it's meaningful and urgent to estimate GHG emissions amount in every sectors. The growing concern about reducing GHG emissions has been shared by many water companies. This work aims to identify and estimate GHG emissions from the activities of drinking water treatment plants (DWTPs). According to the GHG protocol, the GHG emission inventory of DWTPs covers the sources of fossil fuel combustion, reservoir emissions, electricity and heat supply, use of chemicals and additives, disposal of waste, transportation, operation and maintenance. The tool was tested by nine DWTPs, which had an average GHG emission intensity of 0.225 kg CO2-eq/m3. The GHG emission intensities range from 0.167 kg CO2-eq/m3 to 0.272 kg CO2-eq/m3. The main source of GHG emissions is electricity supply, followed by the use of chemicals and additives. According to the average emission intensity, the estimated total amount of GHG emissions from DWTPs in China is about 1.82 × 107 t/a, corresponding to 0.15 % of the total GHG emission in China. The proposed GHG sources and emissions help decision-makers and DWTPs companies estimate GHG emissions more accurately and undertake GHG reduction measures.

Modeling greenhouse gas emissions from riverine systems: A review

Despite the recognized importance of flowing waters in global greenhouse gas (GHG) budgets, riverine GHG models remain oversimplified, consequently restraining the development of effective prediction for riverine GHG emissions feedbacks. Here we elucidate the state of the art of riverine GHG models by investigating 148 models from 122 papers published from 2010 to 2021. Our findings indicate that riverine GHG models have been mostly data-driven models (83%), while mechanistic and hybrid models were uncommonly applied (12% and 5%, respectively). Overall, riverine GHG models were mainly used to explain relationships between GHG emissions and biochemical factors, while the role of hydrological, geomorphic, land use and cover factors remains missing. The development of complex and advanced models has been limited by data scarcity issues; hence, efforts should focus on developing affordable automatic monitoring methods to improve data quality and quantity. For future research, we request for basin-scale studies explaining river and land-surface interactions for which hybrid models are recommended given their flexibility. Such a holistic understanding of GHG dynamics would facilitate scaling-up efforts, thereby reducing uncertainties in global GHG estimates. Lastly, we propose an application framework for model selection based on three main criteria, including model purpose, model scale and the spatiotemporal characteristics of GHG data, by which optimal models can be applied in various study conditions.

Improved method for calculating CO2 emission from industrial solid wastes combustion system based on fossil and biogenic carbon fraction

Waste-to-Energy (WtE) technology is the most effective solution for managing non-recyclable wastes through mass burning and energy recovery. Owing to the significant volumes of plastics in China's industrial solid wastes (ISW), a large amount of greenhouse gases (GHG) is generated during the incineration process. Therefore, monitoring GHG emissions from WtE facilities is essential. Owing to the lack of suitable accounting models and characterized fossil carbon fraction (FCF) data, current studies use default values provided by the Intergovernmental Panel on Climate Change's (IPCC), which increases calculation inaccuracies. Therefore, this study established an improved method to accurately account for carbon emissions during solid waste incineration by firstly using radiocarbon dating by accelerator mass spectrometry (AMS) technique to determine the FCF of the solid waste components in China. Monte Carlo analysis was employed to perform the sensitivity analysis, and the results indicated that there was a significant deviation between the measured value and IPCC's default values of FCF, 3.2, 32.48, 93.39, 93.76, 90.49, and 93.8 % for paper, cotton, synthetic textiles, artificial rubber, artificial leather, and plastics, respectively. By replacing coal with ISW in a 2 × 110 t/h circulating fluidized bed boilers, 9.251 × 104 t CO2-eq emissions were reduced, and the carbon emission factor reached 0.56 t CO2-eq/t waste. This study complements the research gap fossil carbon data of wastes in the IPCC guidelines and provides a more accurate and effective way to calculate carbon emissions during ISW incineration treatment.

A review of mitigation technologies and management strategies for greenhouse gas and air pollutant emissions in livestock production

One of the key issues in manure management of livestock production is to reduce greenhouse gas (GHG) and air pollutant emissions, which lead to significant environmental footprint and human/animal health threats. This study provides a review of potentially efficacious technologies and management strategies that reduce GHG and air pollutant emissions during the three key stages of manure management in livestock production, i.e., animal housing, manure storage and treatment, and manure application. Several effective mitigation technologies and practices for each manure management stage are identified and analyzed in detail, including feeding formulation adjustment, frequent manure removal and air scrubber during animal housing stage; solid-liquid separation, manure covers for storage, acidification, anaerobic digestion and composting during manure storage and treatment stage; land application techniques at appropriate timing during manure application stage. The results indicated several promising approaches to reduce multiple gas emissions from the entire manure management. Removing manure 2-3 times per week or every day during animal housing stage is an effective and simple way to reduce GHG and air pollutant emissions. Acidification during manure storage and treatment stage can reduce ammonia and methane emissions by 33%-93% and 67%-87%, respectively and proper acid, such as lactic acid can also reduce nitrous oxide emission by about 90%. Shallow injection of manure for field application has the best performance in reducing ammonia emission by 62%-70% but increase nitrous oxide emission. The possible trade-off brings insight to the prioritization of targeted gas emissions for the researchers, stakeholders and policymakers, and also highlights the importance of assessing the mitigation technologies across the entire manure management chain. Implementing a combination of the management strategies needs comprehensive considerations about mitigation efficiency, technical feasibility, local regulations, climate condition, scalability and cost-effectiveness.

Mitigation of gaseous emissions from dairy livestock: A farm-level method to examine the financial implications

Feeding the world's population while minimising the contribution of agriculture to climate change is one of the greatest challenges facing modern society. This challenge is particularly pronounced for dairy production where the carbon footprint of products and the mitigation costs are high, relative to other food stuffs. This paper reviews a number of mitigation measures that may be adopted by dairy farmers to reduce greenhouse gas emissions from their farms. A simulation model is developed to assess the cost-benefit of a range of mitigation measures. The model is applied to data from Ireland, a country with a large export-oriented dairy industry, for a range of farms including top, middle and bottom performing farms from a profitability perspective. The mitigation measures modelled included animal productivity, grass production and utilisation, better reproductive performance, early compact calving, reduced crude protein, decreased fertiliser N, protected urea, white clover, slurry tank cover and low emission slurry spreading (LESS). The results show that over half of the greenhouse gas abatement potential and most of the ammonia abatement potential were realised with cost-beneficial measures. Animal and feed-related measures that increased efficiency drove the abatement of GHG emissions. Low-emission slurry spreading was beneficial for the bottom and middle one-third of farms, while protected urea and reducing nitrogen use accounted for most of the ammonia abatement potential for the most profitable farms. Results showed that combining mitigation measures resulted in a decrease of 23%, 19%, and 12% in GHG emissions below 2020 levels for the bottom, middle, and top performing dairy farms, respectively. The findings imply that top dairy farms, that are already managed efficiently and optimally, may struggle to achieve the national and international GHG reduction targets with existing technologies and practices.

Hybrid life-cycle and hierarchical archimedean copula analyses for identifying pathways of greenhouse gas mitigation in domestic sewage treatment systems

Electricity consumption and anaerobic reactions cause direct and indirect greenhouse gas (GHG) emissions within domestic sewage treatment systems (DSTSs). GHG emissions in DSTSs were influenced by the sewage quantity and the efficacy of treatment technologies. To address combined effects of these variables, this study presented an approach for identifying pathways for GHG mitigation within the DSTSs of cities under climate change and socio-economic development, through combining life cycle analysis (LCA) and the Hierarchical Archimedean copula (HAC) methods. The approach was innovative in the following aspects: 1) quantifying the GHG emissions of the DSTSs; 2) identifying the correlations among temperature changes, socioeconomic development, and domestic sewage quantity, and 3) predicting the future fluctuations in GHG emissions from the DSTSs. The effectiveness of the proposed approach was validated through its application to an urban agglomeration in the Pearl River Delta (PRD), China. To identify the potentials of GHG mitigation in the DSTSs, two pathways (i.e., general and optimized) were proposed according to the different technical choices for establishing facilities from 2021 to 2030. The results indicated that GHG emissions from the DSTS in the PRD were [3.01, 4.96] Mt CO2eq in 2021, with substantial contributions from Shenzhen and Guangzhou. Moreover, GHG emissions from the sewage treatment facilities based on Anaerobic-Anoxic-Axic (AAO) technology were higher than those based on other technologies. Under the optimized pathway, GHG emissions, contributed by the technologies of Continuous Cycle Aeration System (CASS) and Oxidation Ditch (OD), were the lowest. Through the results of correlation analysis, the impact of socioeconomic development on domestic sewage quantities was more significant than that of climate change. Domestic sewage quantities in the cities of the PRD would increase by 4.10%-28.38%, 17.14%-26.01%, and 18.15%-26.50% from 2022 to 2030 under three Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5. These findings demonstrated that the capacities of domestic sewage treatment facilities in most cities of the PRD should be substantially improved from 0.12 to 2.99 times between 2022 and 2030. Under the optimized pathway, the future GHG emissions of the CASS method would be the lowest, followed by the OD method.

Effectiveness of conservation messages to reduce households' GHG emissions: A serious-gaming experiment

Households play a critical role in reducing greenhouse gas emissions. However, there have been few studies of household conservation from the perspective of the nexus of food, energy, and water (FEW) consumption. This study's objective is to understand the effects of different types of intervention messages for inducing conservation of FEW resources and reducing carbon emissions at the household level in the U.S. Employing a serious-gaming approach, we developed the HomeRUN (Home Role-play for Understanding the Nexus) game, which allows players to act as homeowners and take behavioral and technological upgrade actions in a computer-simulation setting. The types of messages tested include social comparisons and resource-reduction measures across FEW sectors as well as information about the health, economic, and environmental impacts of FEW consumption. A game experiment with U.S. university students finds that social-comparison messages on food and energy consumption, but not on water, lead to significant reductions in household carbon emissions. In addition, messages associated with each type of FEW resource tend to lead to an immediate action corresponding to the particular FEW domain. These insights support a prioritization of intervention messaging for coordinated FEW conservation efforts at a household level.

Integrating work into life helps reduce residential greenhouse gas emissions

Work from home (WFH) creates work-life integration by moving work into traditional life at home, but its influence on residential greenhouse gas (GHG) emissions remains unclear. In this study, an activity-based bottom-up model was developed to analyze the time-use patterns (activity durations and timeline of a typical day) of participants under WFH and traditional home life and to quantify their residential GHG emissions. Under WFH, participants generated an average of 9.03 kg CO2e/person/day, primarily attributed to space heating and cooling, cooking, grooming, work, and watching TV and movies. Notably, the GHG footprints varied across groups (8.08-9.93 kg CO2e/person/day) due to different work and household responsibilities and leisure time and varied with climate region (4.99-10.63 kg CO2e/person/day) because of emission factors of electricity, space heating and cooling, and cooking. Compared with traditional life at home (10.06 kg CO2e/person/day), WFH participants spent less time on almost all major activities (especially sleeping and watching TV and movies) to focus on work, enabling an 11.34% (1.02 kg CO2e/person/day) mitigation of GHG emissions. The reductions also varied by group and climate region, mainly associated with laundry, cooking, and watching TV and movies. Opportunities to reduce GHG emissions under WFH lie in targeting key activities, balancing the time spent on various activities, and developing group- and spatial-specific strategies. This study provides a systematic and high-resolution estimation of residential GHG emissions under WFH and traditional home life, with a complete system boundary, activity-specific considerations, and countrywide understanding. The findings reveal the environmental impact of work-life integration from the residential perspective and can aid residents and policymakers in utilizing decarbonization opportunities to advance low-carbon living under WFH.

Predicting and assessing greenhouse gas emissions during the construction of monorail systems using artificial intelligence

Based on partial data, this paper uses BP neural network optimised by particle swarm optimisation algorithm to predict the total greenhouse gas (GHG) emissions of the line in the construction phase. The GHG emission efficiency is analysed by SBM (Slacks-Based Measure) super efficiency method. Finally, the grey relational analysis (GRA) is applied to sort the GHG emission correlation factors. Based on the existing design and quota document data of 16 stations and 16 sections of the Wuhu Monorail Line 1, we have employed a neural network optimized by particle swarm optimization algorithm to predict the total emissions of greenhouse gases during the construction phase of the entire line consisting of 25 stations and 24 sections. The GHG emissions of all stations and sections are 29,300 tons and 21,000 tons. The technical efficiency, pure technical efficiency, and scale efficiency of the stations and sections were high. As for stations, the order of influence degree is metal material consumption (0.9731) > cost (0.9486) > electric energy consumption (0.9481) > station area (0.9109) > concrete and cement consumption (0.9032) > other material consumption (0.8831) > gasoline and diesel consumption (0.7258). For the section, the order of influence degree is cost (0.9766) > concrete (0.9581) > steel reinforcement (0.9483) > other steels (0.874) > section length (0.8337) > power energy consumption (0.7169) > wood consumption (0.6684).

Life cycle assessment of novel thermochemical - biochemical biomass-to-liquid pathways for sustainable aviation and maritime fuel production

This paper aims to carry out an integrated Life Cycle Assessment (LCA) to evaluate the environmental performance of a novel thermochemical-biochemical biomass-to-liquid pathway for sustainable aviation and maritime biofuel production. Five scenarios are defined, consideringdifferent types of biomass feedstock and biorefinery locations, in different geographically dispersed European countries. The results indicate that the replacement of conventional aviation and maritime fuels with sustainable biofuels could reduce Greenhouse Gases (GHG) by 60-86%, based on feedstock type. When the renewable share in the electricity mix reaches 100% (in 2050), the GHG emissions will experience a great decrease (26% - 68%), compared to 2022 levels. The non-renewable energy consumption will also decrease (by 56% - 83%), with results strongly affected by the electricity mix of the European country considered. This study demonstrates that the deployment of biomass-to-jet/marine fuel pathways could favor the industrial adoption of circular economy strategies for transport biofuels production.

Proper C/N ratio enhances the effect of plant diversity on nitrogen removal and greenhouse effect mitigation in floating constructed wetlands

Treating wastewater with low carbon-to-nitrogen (C/N) ratios by constructed wetlands (CWs) is still problematic. Adding chemicals is costly and may cause secondary pollution. Configuring plant diversity in substrate-based CWs has been found to be a better way to treat low-C/N wastewater, but wastewater treatment in floating CWs needs to be studied. In this study, wastewater with C/N ratios of 5 and 10 were set in simulated floating CWs, and 9 combinations with plant species richness (SR) of 1, 3, and 4 were configured. The results showed that (1) increasing SR improved the total N mass removal (NMR) by 29% at a C/N ratio of 5 but not 10; (2) the presence of Oenanthe javanica in the microcosms increased the NMR by 13% and 20% with C/N ratios of 5 and 10, respectively; (3) increasing SR mitigated the net global warming potential (GWP) by 120% at a C/N ratio of 5 but not 10; and (4) a Hemerocallis fulva × O. javanica × Echinodorus parviflours × Iris hybrids mixture resulted in a high NMR and low net GWP. In summary, assembling plant diversity in floating CWs is an efficient and clean measure during the treatment of wastewater with a C/N ratio of 5.

Life Cycle Greenhouse Gas Emissions of CO2-Enabled Sedimentary Basin Geothermal

The expansion of renewable energy and the large-scale deployment of carbon dioxide (CO2) capture and storage (CCS) can decarbonize the power sector. The use of CO2 to extract geothermal heat from naturally porous and permeable sedimentary basins to generate electricity (CO2-plume geothermal (CPG) system) presents an opportunity to simultaneously generate renewable energy and geologically store CO2. In this study, we estimate the life cycle greenhouse gas (GHG) impacts of CPG systems through 12 scenarios in which CPG systems are combined with one of six CO2 sources (e.g., bioenergy with carbon capture and storage (BECCS) and iron and steel facilities) and operate in two geological settings. We find the life cycle GHG emissions of CPG systems ranging from -0.25 to -6.18 kg CO2eq/kWh. CPG systems can achieve the highest emissions reductions when utilizing the CO2 captured from BECCS. We evaluate uncertainty through a Monte Carlo simulation, demonstrating consistent net reductions in life cycle emissions and a local, one-parameter-at-a-time sensitivity analysis that identifies the CO2 capture capacity as the high-impact parameter of the results. Through the production of electricity, CPG systems can provide additional environmental benefits to the deployment of large-scale CCS.