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Methane, both enteric and from manure management, is the most important greenhouse gas from ruminant livestock, and its mitigation can deliver substantial decreases in the carbon footprint of animal products and potentially contribute to climate change mitigation. Although choices may be limited, certain feeding-related practices can substantially decrease livestock enteric CH 4 emission. These practices can be generally classified into 2 categories: diet manipulation and feed additives. Within the first category, selection of forages and increasing forage digestibility are likely to decrease enteric CH 4 emission, but the size of the effect, relative to current forage practices in the United States dairy industry, is likely to be minimal to moderate. An opportunity also exists to decrease enteric CH 4 emissions by increasing dietary starch concentration, but interventions have to be weighed against potential decreases in milk fat yield and farm profitability. A similar conclusion can be made about dietary lipids and oilseeds, which are proven to decrease CH 4 emission but can also have a negative effect on rumen fermentation, feed intake, and milk production and composition. Sufficient and robust scientific evidence indicates that some feed additives, specifically the CH 4 inhibitor 3-nitrooxypropanol, can substantially reduce CH 4 emissions from dairy and beef cattle. However, the long-term effects and external factors affecting the efficacy of the inhibitor need to be further studied. The practicality of mass-application of other mitigation practices with proven short-term efficacy (i.e., macroalgae) is currently unknown. One area that needs more research is how nutritional mitigation practices (both diet manipulation and feed additives) interact with each other and whether there is synergism among feed additives with different mode of action. Further, effects of diet on manure composition and greenhouse gas emissions during storage (e.g., emission trade-offs) have not been adequately studied. Overall, if currently available mitigation practices prove to deliver consistent results and novel, potent, and safe strategies are discovered and are practical, nutrition alone can deliver up to 60% reduction in enteric CH 4 emissions from dairy farms in the United States. [ABSTRACT FROM AUTHOR]

• Accounting methods of agricultural methane are summarized. • Influencing factors of emission sources from agricultural sources were analyzed. • Mitigation strategies based on accounting and actual situation are proposed. Methane is one of the major greenhouse gases (GHGs) and agriculture is recognized as its primary emitter. Methane accounting is a prerequisite for developing effective agriculture mitigation strategies. In this review, methane accounting methods and research status for various agricultural emission source including rice fields, animal enteric fermentation and livestock and poultry manure management were overview, and the influencing factors of each emission source were analyzed and discussed. At the same time, it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual situation. Finally, mitigation strategies based on accounting results and actual situation are proposed. This review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation. [Display omitted] [ABSTRACT FROM AUTHOR]

The research objective is to create a mechanism that generates a valid 'sustainability' metric to enable prospective buyers to confidently identify low carbon footprint computers. The necessity is based upon the hypothesis that current product carbon footprint reports for computers are incomparable between brands. While the inconsistency of use-phase emissions has been addressed in prior associated research, supply chain emissions remain an issue. This is due to multiple scope 3 life cycle assessment methodologies being used by manufacturers that produce differing results even when applied to the same device. To test the theory and generate an alternative approach, the research analyses 244 notebook carbon footprint reports to show inconsistencies caused by five different methodologies. Based on the findings, an alternative approach to comparing supply chain impact is proposed that enables comparison between results. The new metric first generates an average scope 3 carbon footprint baseline value by device type (e.g. notebook). This is then reduced by specific values depending upon actions undertaken by manufacturers when calculating their original carbon footprint report. This includes deductions to the baseline value achieved by including high percentages of production and transport primary data, plus the availability and affordability of offerings that will extend device useful life spans to drive demand displacement. This includes warranty duration and cost plus ease of repair. The research finds that current methodologies create a range of inconsistency of +106% when used to calculate the carbon footprint of the same device and +142% when calculating similar device types. Therefore, the hypothesis of scope 3 emissions being incomparable is validated. Comparatively, the newly proposed mechanism shows a reduced range of inconsistency of 18% when demonstrated. As such, it is recommended that the new approach be applied to the latest version of the world's leading computer eco-label certification, TCO Certified version 10, in 2024. Doing so will enable organisations to confidently select low carbon footprint devices on a global scale and therefore meaningfully support the United Nations sustainable development goals of responsible consumption and production and ultimately climate action. [ABSTRACT FROM AUTHOR]

The pressure on reducing greenhouse gas emissions has increased since the focus on climate change mitigation has grown. As the human development index is directly related to per capita energy consumption, sustainable energy production with reduced carbon footprint is the essential pathway for cleaner environment. Over numerous existing biological processes, hydrogen production via photo fermentation and photolysis of water is considered a more sustainable and economical method of hydrogen production. While both biological modes suffer from certain limitations, such as low yields and low production rates, practical implementation is still a long way off due to these limitations. The unique properties of nanomaterials (NMs) can help increase the efficiency of the biomass to biohydrogen process in significant ways. Applications of organic and inorganic nanoparticles in photocatalytic and photo fermentative hydrogen production is discussed in this paper. This review reports a wide range of applications of nanomaterials including the details of photo fermentative microorganisms and their mechanism of action. The maximum photo fermentative bio-H 2 production was reported in the presence of SiC–Fe 3 O 4 (3.02 mol H 2 /mol acetate), Ni (41 mol H 2 /mol sugar), graphite-C 3 N 4 (64.2 mol H 2 /mol sugar) whereas photocatalytic bio-H 2 yield was highest when Pd–Ni/CdS (54 mmol/g.h), Ni-MO/g-C 3 N 4 (1785 mmol/g.h) and CuO/TiO 2 (20.3 mmol/g.h) nanoparticles were employed. To design photocatalytic systems for practical and scalable use, the future research should be focused on deeper theoretical knowledge of mechanisms of light harvesting, ± charge separation and transport, surface biochemical reactions, semiconductor–liquid interactions, and reactor dynamics. [Display omitted] • Recent developments for improving water photolysis and photo-fermentation are reviewed. • Applications of organic and inorganic nanoparticles in hydrogen production are discussed. • The working principle and mechanism of hydrogen production are discussed. • The influence of key operating factors are presented. • Scope for future research was presented. [ABSTRACT FROM AUTHOR]

To effectively mitigate climate change, policymakers worldwide established various GHG tracking and trading systems. In the light of ambitious climate goals, stricter regulations, and increasing demand for climate action, various groups such as researchers and governmental institutions suggested additional approaches. This paper addresses the complexity that arises from the breadth of suggested approaches and implemented systems for GHG tracking and trading. By doing so, it synthesizes relevant dimensions in a way that is understandable to enterprises and policymakers, enabling them to design meaningful systems incorporating the reduction of GHG emissions and advance cleaner production. Therefore, this paper presents a first-of-its-kind taxonomy of GHG tracking and trading approaches through a systematic literature review. It illustrates ten main design and implementation dimensions with 30 corresponding characteristics. To accelerate decarbonization, this paper sets impulses for future GHG tracking in the electricity sector based on semi-structured expert interviews. Consecutively, it provides policy directions for CO 2 -adaptive decision-making for enterprises, formulated as a Call for Action with seven prospective questions. These include, for example, questions concerning technical aspects like data management, legal issues like the sufficiency of existing data security and privacy regulations, as well as economic topics like the calculation of an appropriate local and temporal granularity. • Presenting a first-of-its-kind taxonomy of GHG tracking and trading approaches through a systematic literature review. • Creating targeted knowledge for enterprises and policymakers for designing meaningful systems to reduce GHG emissions. • Setting impulses for future GHG tracking in the electricity sector based on semi-structured expert interviews. • Providing policy directions for CO 2 -adaptive decision-making for enterprises, formulated as a Call for Action. [ABSTRACT FROM AUTHOR]

• Climate policy should be diversified to meet the needs of all countries. • The ability of renewable energy to solve the emissions problem is questioned. • The energy efficiency has no statistically significant changes in 2010–2020. • There is a contradiction between Sustainable Development Goals 7 and 13. Improving energy efficiency is considered to be important and cost-effective strategies to reduce greenhouse gas emissions, which is crucial in the face of global climate change. This study hypothesizes that there are significant differences in the impact of energy efficiency on economic and energy systems. Using quantile regression method, the impact of economic and energy characteristics on energy-related greenhouse gas emissions in 120 countries over the period 2010–2020 is investigated. Detailed analyses are conducted by dividing the countries into 12 groups based on gross national income per capita (Atlas method) and the share of resource rents in gross domestic product. A macro-level system of indicators for assessing energy efficiency is proposed, which can be linked to the economic and energy characteristics of the systems: National Energy Efficiency, Energy Intensity Ratio, Primary Energy Production Efficiency, Industrial Sector Energy Efficiency, Share of Low Carbon Energy, Population Energy Efficiency. The findings show that (1) global energy efficiency has remained largely unchanged over the decade; (2) there are differences in energy efficiency between fossil fuel producing and non-fossil fuel producing countries; (3) the factors that have an inverse effect on emissions in fossil fuels dependent countries include industrial energy efficiency and population energy efficiency, which are far from exhausting their potential; (4) despite the recognized importance of energy efficiency, its impact on reducing greenhouse gas emissions globally has been unnoticeable. The study highlights that Sustainable Development Goals 7 and 13 on energy affordability and emission reductions are conflicting and require harmonization of mechanisms to achieve them, such as balancing climate change mitigation investments, identifying the potential for energy efficiency improvements across economy or improving energy saving practices. The overall conclusion suggests that there is an urgent need to review current decarbonization and energy efficiency initiatives, given the lack of significant global progress in reducing greenhouse gas emissions or improving energy efficiency between 2010 and 2020. [ABSTRACT FROM AUTHOR]

Carbon tax is a policy instrument that facilitate the phase-out of coal as a chemical feedstock and help China achieve an early carbon peak. However, the policy design is challenged by the complex dynamics of global warming potentials (GWP) from upstream methane emissions, which have a short atmospheric lifetime but a high climate impact. In this study, we compared the life-cycle GWP of two propylene production routes in China: Coal-to-Olefin (CTO) and Propane Dehydrogenation (PDH). We also conducted a cost-profit analysis that incorporates the carbon tax, considering uncertainties in the dynamic radiative forcing of methane. We derived a range of optimal carbon tax rates that can enhance the economic competitiveness of low-carbon propylene routes PDH and discourage the expansion of coal-fed CTO propylene routes. Results show that, for the propylene sector in China, the carbon tax rate should be between 86 and 600 Chinese Yuan (CNY) or 12–84 US dollars (USD) per ton of carbon dioxide equivalent (CO2e), which corresponds to 1–10% of the typical propylene price in the Chinese market. Our study provides spatiotemporal insights into the carbon tax for China's propylene sector to decarbonize and control upstream methane emissions. Since propylene is one of the key raw materials for chemical (e.g., plastic) productions, our analysis contributes to the climate benefits of global chemical trade. • Carbon tax contributes to controlling upstream methane emissions from coal-based chemical production. • Time-horizon is crucial for taxing carbon, especially as short-lived greenhouse gas emissions affect propylene producers' profits. • Carbon tax is necessary at provincial scale since the intensity of methane emissions from coal and propane feedstock supply chains vary regionally. [ABSTRACT FROM AUTHOR]

We perform an ex-ante life cycle assessment, integrating cradle-to-gate greenhouse gas emissions into an off-grid energy system model. By applying a multi-objective optimization, minimizing both costs and carbon dioxide equivalent (CO 2 e) emissions, we find the Pareto boundary between these two goals. As a case study, we chose the power supply to an astronomical observatory in Chile, using mostly solar power and energy storage in batteries and hydrogen. We compare the ex-ante study to a prior ex-post life cycle assessment, and furthermore dive into sensitivities of our model regarding component lifetimes and costs. We find (i) low-hanging fruit in lowering emissions with small cost increases, (ii) ex-ante life cycle assessments' possibility to find less CO 2 e intensive power systems compared to ex-post conducted studies, (iii) a pronounced sensitivity of the optimization model on assumed lifetimes of energy storage components. This study shows the importance of including life cycle CO 2 e emissions into the optimization objective of energy system models. This method uncovers the environmental and economic trade-offs associated with high shares of renewable energies in off-grid energy systems. • We integrate life cycle assessment (LCA) into an off-grid energy system optimization. • The applied case study powers a remote astronomical telescope in Chile. • A multi-objective optimization finds Pareto curves at varying costs and lifetimes. • Low-hanging fruit shows low additional system costs to reduce CO 2 e impacts. • In contrast, a separate LCA did not find such trade-offs in costs and CO 2 e emissions. [ABSTRACT FROM AUTHOR]

• Buildings potential for climate change mitigation is high. • Mitigation actions in the buildings sector can have significant social and economic values. • These enable the achievement of 4 SDGs, reinforce 7 other. • And are linked to the achievement of 5 SDGs (SDG3, SDG7, SDG8, SDG11, and SDG13). • Trade-offs were identified for 9 SDGs. Buildings are responsible for a big part of total GHG emissions; therefore, their climate change mitigation potential is high. But research shows that mitigation actions in the sector can have significant social and economic values beyond reduction of energy consumption and the associated GHG emissions. This paper summarizes these multiple impacts of mitigation actions in buildings, which are related to microeconomic and macroeconomic effects, health impacts, environmental benefits, better management of natural resources, impacts on social well-being, and energy security implications, and assesses their interactions (synergies and trade-offs) with the UN SDGs. The findings of our analysis show that climate change mitigation actions in buildings enable the achievement of 4 SDGs, reinforce 7 others, and are inextricably linked to the achievement of 5 SDGs, namely SDG3: good health and well-being, SDG7: affordable and clean energy, SDG8: decent work and economic growth, SDG11: sustainable cities and communities, and SDG13: climate action. On the other hand, trade-offs were identified for 9 SDGs, with rather minor implications, which can be further eliminated with the implementation of appropriate policies. [ABSTRACT FROM AUTHOR]

Cocoa production is a leading driver of deforestation in the humid-tropics of West Africa. Reconciling climate change mitigation with livelihoods of farmers requires identification of production strategies to concurrently improve yield and profit while curtailing emissions of greenhouse gases (GHG). Using a 2021 plot-survey conducted in Ghana's Eastern region, we evaluated yields, GHG emissions, and value of production (VOP) (a profit indicator) across a typology representing the diversity of systems at plot-level. The typology was constructed by first stratifying plots according to shade levels and variety (hybrid vs. Amazonia) which resulted in three systems: Hybrid sun , hybrid variety under full-sun (little to no shade); Hybrid shade , hybrid and moderate shade (13–25 shade trees ha−1); and Amazonia, Amazonia under predominantly moderate shade. Next, factor analysis and clustering were used to group plots within each system according to cocoa yield, vegetation, management, and (local) climate conditions. Cluster analysis showed that fertiliser, weeding, pruning, hand pollination, cocoa tree density, and shade tree densities of differing heights were most influential for determination across systems. Hybrid shade had the highest net GHG removal rate at −6.8 ± 1.7 (± 95% CI) Mg CO 2 eq ha−1 yr−1: 48% and 127% higher (emissions more negative) respectively over Amazonia and Hybrid sun. Hybrid shade additionally had the highest average and least variable VOP among production systems at 669 ± 564 USD ha−1 yr−1, compared to Hybrid sun and Amazonia at 404 ± 442 and 213 ± 280 USD ha−1 yr−1 respectively. These results point to hybrid cocoa grown under moderate shade of 13–25 shade trees ha−1 as optimal for reconciling climate change mitigation with development in West African cocoa. • Study concurrently evaluates financial profits and GHG balances (N 2 O & CH 4 emissions, CO 2 removals) in West African cocoa. • Plot-level indicators are evaluated across a typology obtained from sample-stratification and clustering. • Hybrid cocoa under moderate shade (13-25 shade trees ha-1) had GHG removal increment of 127% over same variety without shade. • This system too had higher mean profits, thus best reconciling GHG mitigation and economic development for the region. [ABSTRACT FROM AUTHOR]

Efforts to enhance greenhouse gas (GHG) emission reduction in East Asia play a pivotal role on both global and regional scales in advancing climate mitigation strategies. This study aimed to better constrain anthropogenic CO 2 emission estimates by expanding the network of near-surface in-situ stations for CO 2 observations across South Korea. To achieve an optimal CO 2 network design, we conducted an Observing System Simulation Experiment (OSSE) coupled with the Stochastic Lagrangian Transport model (STILT), utilizing meteorological data from the Korean Integrated Model (KIM). Our inversion setup incorporated two CO 2 emission datasets with a 0.1o resolution: EDGAR v6 for prior emissions and GRACED for truth emissions. A uniform model-mismatch error of 3 ppm was introduced across sites. The effectiveness of the existing five in-situ stations, termed the base network, in South Korea was evaluated to gauge their ability to constrain CO 2 surface flux estimates. However, the findings revealed a reduction in flux uncertainty of only 29.2%, which fell short of the desired uncertainty reduction goal. In this base network, the Lotte World Tower (LWT: 37.5126°E, 127.1025°E) in Seoul and the Anmyeondo (AMY: 36.538576° N, 126.330071° E) site in Taean county stood as major contributors, with estimated reductions of 17.48% and 6.35%, respectively. Consequently, we proposed and developed an extended network, identifying seven candidate sites based on consideration of logistical factors, existing infrastructures, and proximity to the emission source regions. An incremental optimization scheme ranked their contributions, resulting in an additional 25% reduction, bringing the total to 54.13%. However, it is noteworthy that diminishing returns (ranging from 13% to less than 0.1%) were observed with an increase in station count mainly due to the possibility that adding a station earlier in the sequence might render subsequent stations redundant. Despite this, the proposed CO 2 network successfully reduced uncertainty in emissions, narrowing the gap with the objectives of the Global Greenhouse Gas Watch (G3W). • Designing CO 2 near-surface observation network over South Korea. • New stations selected considering logistic factors, existing infrastructures, and proximity to emission sources. • The base network was able to reduce 29.18% of the uncertainty in CO 2 emissions. • Extending network, by adding new seven candidate sites, led to a total uncertainty reduction of 54.13%. [ABSTRACT FROM AUTHOR]

Natural climate solutions (NCS) offer immediate and cost-effective ways to tackle the climate crisis by transforming atmospheric carbon to soil carbon or avoiding greenhouse gas emissions. However, the climate mitigation potential and economic costs of NCS for cropping systems in China remain inconclusive. The major objectives of this study are (i) to estimate the NGHG reduction potential across Chinese main cropping systems caused by NCS, (ii) to quantify the economic costs of adopting optimal management with different abatement potentials. The Denitrification-Decomposition (DNDC) model was used to estimate the NGHG, including SOC sequestration, N 2 O emissions, and CH 4 emissions. After calibration, we ran the DNDC model with derived data at municipality-level. We estimated the NGHG under current management, adopting optimal management individually, and integrated optimal management to project the maximum NGHG reduction potential caused by NCS. We used the marginal abatement cost method to estimate the economic cost. The four natural climate solutions, N fertilization management (NFM), straw returning management (SRM), tillage management (TM), and rice irrigation management (RIM) can reduce national NGHG in main cropping systems by approximately 118.8 Tg CO 2 -eq, 116.3 Tg CO 2 -eq, 35.2 Tg CO 2 -eq, and 74.4 Tg CO 2 -eq, respectively. The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq, equivalent to 90.2% of current NGHG, and 80% of which can be realized at the price of CN¥ 285 (Mg CO 2 -eq)−1. We further identify the priority NCS for different crops and regions and conclude that nitrogen fertilization management should be the priority NCS at the national level. Our findings highlight the great potential of NGHG reduction by adopting NCS precisely and the importance of optimizing agricultural management as a whole, and they will help policy makers to develop smart-agriculture in China. [Display omitted] • Estimating net greenhouse gas emissions (NGHG) reduction potentials of agriculture. • IPCC recommended tier 3 method was applied for seven cropping systems in China. • The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq. • 80% of NGHG mitigation can be realized at the price of CN¥ 285 (Mg CO 2 -eq)−1. • The priority NCS was identified for different crops and regions. [ABSTRACT FROM AUTHOR]

Drained peatland currently contributes 7.5% of Germany's total national greenhouse gas emissions. The National Peatland Protection Strategy adopted by the German government in 2022 recognizes that these emissions need to be reduced significantly to meet the country's climate change mitigation commitments. The present study employs a global dynamic computable general equilibrium model to assess the economic and greenhouse gas emission impacts of alternative agriculture-focused peatland rewetting scenarios for Germany up to 2030. In contrast to partial-analytic approaches, the global general equilibrium approach allows to take consistent account of economic ripple-on effects and carbon leakage effects triggered by peatland rewetting. The results suggest that in the medium term towards 2030 a reduction in annual emissions from agricultural peatland use by up to 45% are attainable at marginal private abatement costs between 27 and 61 Euro/tCO 2 e. Carbon leakage effects due to induced indirect land use change in Germany and the rest of the European Union reduce the global net emission reduction impact by 0.7 to 1.0% of the direct emission reduction. The effects on food prices remain small in all scenarios. In conclusion, a sizable reduction of Germany's land-use-related emissions is achievable at a low macroeconomic cost by moving beyond the moderate ambitions of the National Peatland Restoration Strategy. [ABSTRACT FROM AUTHOR]

As a response to the increasing threat to sport events from climate change and expectations around climate change mitigation, sport event managers increasingly engage in environmentally-related initiatives that aim to reduce GHG emissions. One of the major contributors to GHG emissions at large sport events is spectators' travel and, thus, their associated modal choices. Building on the Sport Logistics Framework (SLF) and using the case study of Rapid Vienna, the largest football club in Austria, this study investigates spectators' modal choice to systematically assess the total GHGs emitted by spectators at a professional football home game. Data was obtained from two sources: a) an extensive data set collected on Rapid Vienna season ticket holders, and b) three surveys at home games which, together, constituted 3317 valid responses. The calculation of the GHG emissions resulted in 99,548 kg GHG emissions per home game or 6.0 kg GHG emissions per spectator. It was also found that 42.4 per cent spectators arriving by car emit 71.6 per cent of GHG emissions, while in contrast, 52.8 per cent of spectators using public transport emit 27.1 per cent of GHG emissions. The results also indicate that the possession of an annual public transport ticket seems to determine travel behavior, i.e. the majority of spectators with an annual ticket are using it, while spectators without a ticket are using a car. As such, this paper not only provides an opportunity for academics and managers to benchmark the data in order to identify initiatives to reduce the impact of GHG emissions, but also allows for the systematic measuring of the environmental impact of fan and spectator travel. • Fan travel to professional football games is a major contributor to GHG emissions. • We assess fans' modal choices and their carbon footprint at a football home game. • The home game emits a total 99,548 kg GHG emissions or 6.0 kg GHG emissions per fan. • We found that 42.4% fans arriving by car emit 71.6% of GHG emissions. • The study allows for benchmarking and systematic measuring of fan travel behavior. [ABSTRACT FROM AUTHOR]

Cities represent unique spaces for climate mitigation where wide-ranging action to reduce emissions meets ambition and collaboration. This research work distils climate neutrality narratives for 362 cities that expressed interest in the European Mission on 100 Climate-Neutral and Smart Cities and focuses on the 112 cities selected to spearhead the process of reaching climate neutrality by 2030 (representing a mitigation potential of 318.3 megatonnes of carbon dioxide equivalent emissions). The method involves steps that profile the characteristics of these cities, enunciate cross-cutting patterns in cities' visions by thematic groupings, and compare 14 contextual factors with 77 possible main barriers. There are both similarities and differences among the results as a basis for learning together and certain barriers can be relatively more dominant in some thematic groupings, such as fragmentation of responsibilities. As a synthesis of the main findings, the original analyses are used to derive and prioritise nine high-level recommendations based on the cities' visions, contextual factors, and expected main barriers. Opportunities for mobilising transformative change relate to transforming siloed into integrated approaches, inclusive climate governance and collaborations, innovative financing, welfare and just transition as well as planning, implementation, and policy coherence. The advances provide pioneering steps for stimulating co-learning processes among Mission Cities and beyond to support the transition to climate neutrality and open up opportunities to progress together in climate action while producing impact with global reach. [Display omitted] • Visions and narratives for achieving climate neutrality by 2030 are enunciated across cities. • The 112 Mission Cities represent an emissions reduction potential of 318.3 MtCO 2 eq. • Thematic groupings are formed by cross-comparing degree of ambition and collaboration. • Recommendations are prioritised based on enablers and barriers in the thematic groupings. • Cross-cutting patterns in cities' visions provide opportunities to stimulate co-learning. [ABSTRACT FROM AUTHOR]

Article 6 of the Paris Agreement establishes the foundation for international carbon markets by allowing Parties to cooperate to achieve their nationally determined contributions (NDCs). The Paris Agreement also embeds the concept of 'net zero' by calling for a balance between anthropogenic emissions of GHGs and removals of GHGs by sinks to be reached in the latter part of this century. All signatory Parties therefore tacitly acknowledge that meeting the Agreement's ambitious climate change mitigation goals relies not only on deep cuts in anthropogenic GHG emissions, but also on the offsetting of residual, hard-to-abate, GHG emission sources through significant increases in carbon removal from the active climate system and the storage of CO 2 in enhanced sinks and reservoirs. In these respects, Article 6 potentially offers a variety of routes to incentivize CO 2 capture and storage (CCS) including through emissions trading but also more novel means of cooperation that focus more specifically on carbon storage and which could potentially address some of the challenges posed for CCS over the past 15 years or so. In order to assess the status and outlook for Article 6 with a focus on CCS activities, we define three potential models for cooperation and undertake a comparative evaluation against the key criteria of effectiveness, environmental integrity, commercial and financial viability, progression and policy performance. We conclude with some observations regarding the factors that may influence the likelihood of these different market models evolving over coming years. [ABSTRACT FROM AUTHOR]

The environmental impact of battery electric vehicles (BEVs), which are an integral part of climate change mitigation measures, depends on charging strategies, such as uncontrolled charging, controlled charging (V1G), and discharging (V2G). However, the impact is unclear because power system operation involves the cost of carbon dioxide (CO 2) emissions and flexibility requirements for imbalances caused by renewable energies. To clarify the robustness of the environmental impact of BEVs, we assessed the interactions between CO 2 prices and flexibility requirements in Japan in 2030 using a production cost model. The results showed that uncontrolled charging increases CO 2 emissions, whereas V1G or V2G reduces them. Further, the impact of BEVs was non-monotonic with respect to CO 2 prices, implying that policymakers should carefully evaluate CO 2 prices to achieve decarbonization as BEVs do not always reduce CO 2 emissions. This study provides useful insights for policymakers in countries with low-cost, inflexible, and high-emission power plants. [ABSTRACT FROM AUTHOR]

Rice, as a main crop, contributes to food security in Asia. However, its by-product, rice straw, poses challenges as it is often disposed of unsustainably. This research investigates the environmental performance of a 1000 m3 rice straw biogas pilot plant in Laguna, Philippines. A lifecycle assessment identified the climate change impact of the biogas system, straw burning and soil incorporation. In addition to GWP100, the global temperature potential's dynamic climate effects were assessed, including integrated radiative forcing and instantaneous temperature effects. The timeframe of the biogenic emission fluxes of rice production is particularly relevant as the sequestered CO 2 during plant growth is partly released as methane and CO 2 , depending on the straw management practices. Straw burning had the highest net emission impact. However, straw incorporation has the highest short-term radiative forcing and temperature increase. The biogas system provided significant short- and long-term GHG emission reduction of up to 68 % when biogas replaced burning or soil incorporation and the use of fossil fuels. Still, considerable uncertainties remain about fugitive methane emissions, handling and post-processing of the digestate. While single GHG emission figures on a GWP100 basis are useful for informing decision-making, this single-metric approach limits understanding of rice production's short- and long-term impacts. Additionally, our assessment emphasises the necessity for governance frameworks that promote sustainable practices in rice farming, as banning rice straw burning may result in less favourable outcomes from soil incorporation, whereas integrating biogas offers a solution benefiting rice-growing communities and global sustainability efforts. • Biogas from rice straw reduces emissions by up to 69 %. • Soil incorporation of straw has highest short-term (20 years) temperature increase. • Assessing more than one metric and timeframe supports more informed decision-making. • Governance frameworks enabling bioenergy integration support SDG 3, 7 and 13. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different INM treatments affected soil N and C fractions; • INM produced one emission peak for CO 2 and CH 4 , whereas two for N 2 O from rice agroecosystem; • Significant positive correlation of dehydrogenase (DH) enzyme with CO 2 and N 2 O emissions; • GHG intensity index and yield of rice increased in the order rice stubble > FYM > Azolla ; • CH 4 emission is the dominant contributor to GHG intensity from the rice agroecosystem. The Intergovernmental Panel on Climate Change recognize to agriculture the responsibility for about 15 % of global anthropogenic greenhouse gas (GHG) emissions, contributing to global warming. The increasing nutrient inputs in industrial agriculture affect the GHG concentration in the atmosphere and varies substantially due to rate and type of fertilizers applied to the crops, making the management more or less sustainable. In this perspective, this study has investigated at small scale the effect of different adjusted agricultural management practices, based on different nutrient dosage, to optimize the effect of rice cropping systems on carbon dioxide (CO 2), methane (CH 4) and nitrous oxide (N 2 O) emissions. Farmyard manure (FYM), rice stubbles and Azolla integrated with chemical fertilizers have been correlated with microbial and enzymatic activities, and with different carbon and nitrogen fractions in acid Inceptisol. Results have revealed that the integrated nutrient management used in rice-rice agroecosystem yielded a peak for CO 2 and CH 4 emissions, whereas two peaks for N 2 O emission. This study has shown an increase in greenhouse gas emission intensity (GHGI) and grain yield of rice in the following order: rice stubbles > FYM > Azolla and it has confirmed CH 4 emission as the dominant contributor to GHGI from the rice-rice agroecosystem. When analyzed together GHGs emission and soil properties, a positive correlation was found with biological properties as well as with the different carbon and nitrogen fractions in soil. The highest GHGI has been highlighted in the treatment where recommended dose of chemical fertilizers has been combined with rice stubbles, primarily due to the increase in CH 4 emissions. In contrast, the lowest GHGI has been exhibited in Azolla treated plot, probably due to the cumulative effects of the photosynthetic rate of Azolla , the release of oxygen from the Azolla roots, and the physical protection capacity of the Azolla cover, which partially avoid the CH 4 diffusion from the standing water. The seasonality did not affect the estimated rates of GHGI that have been lower both in case of winter and autumn rice compared to previous studies, probably for dissimilarities in management practices. Further research is required in other cropping sequences for addressing the ecological contribution of smallholder agriculture to help reducing GHG emissions, thus, mitigating global warming with actions at local scale. [ABSTRACT FROM AUTHOR]

This study investigates the impact of alternative fertilization practices on the yield-scaled global warming potential (YS-GWP) in almond orchards. Almond production is a contributor to greenhouse gas emissions, primarily due to nitrogen-based mineral fertilizers. This research aims to identify strategies that reduce the environmental footprint of almond cultivation while maintaining yield. Field experiments were conducted in an almond orchard using three alternative fertigation practices: Advance Grower Practice (AGP), Pump and Fertilize (P&F), and High Frequency Low Concentration (HFLC). AGP is the current practice used by producers to meet annual N demand for almond tree growth; P&F is a reduction in applied N rate in response to measured N concentrations in the groundwater so that the added N and groundwater N reach the same total N applied; HFLC is a practice of applying smaller N rates per individual event. HFLC uses a greater number of fertigation events to reach similar total annual N load as other treatments. Cumulative N 2 O and CH 4 emissions were used to determine GWP by converting the emissions to carbon dioxide equivalents (CO 2 eq) within a 100-year horizon. Nitrous oxide emissions were multiplied by a radiative forcing potential CO 2 eq of 298 and CH 4 by 25 (UNFCCC, 2007). The results revealed that both P&F and HFLC reduced the YS-GWP compared to AGP. HFLC demonstrated 52–78% decrease in GWP per unit of almond yield compared to AGP, while P&F showed 48–58% decrease over AGP. These reductions were attributed to the reduced nitrous oxide emissions associated with P&F and HFLC. Further, P&F and HFLC tended to have higher N use efficiency than AGP. We demonstrate that adopting alternative fertilization practices can effectively mitigate the environmental footprint of almond orchards while maintaining crop yields. These practices offer viable options for almond growers to reduce greenhouse gas emissions, enhance sustainability, and contribute to climate change mitigation. • Applying nitrogen fertilizer at a lower amount and higher frequency reduces nitrous oxide emissions. • This practice tends to have higher nitrogen use efficiency than standard practice. • It maintains commercial yields at the same level as the standard practice. • It lowers Yield Scaled Global Warming Potential more than the standard practice. [ABSTRACT FROM AUTHOR]

The ocean is increasingly used for industry, energy and recreation or protected for conservation, resulting in increasing spatial restrictions for fisheries. Simultaneously, producing seafood with a low climate footprint is becoming increasingly important. Despite this, the effects of spatial restrictions on the emissions of fishing fleets are poorly known. In the Northeast Atlantic, the withdrawal of the United Kingdom from the EU (Brexit) meant that the UK regained autonomy in its Exclusive Economic Zone (EEZ). This suddenly imposed a spatial restriction for several foreign fishing fleets targeting Northeast Atlantic mackerel (Scomber scombrus). Here, we use this natural experiment and open fisheries data to investigate how Brexit affected the performance and emissions of the Norwegian mackerel fishery. As the fleet was excluded from fishing grounds in the UK, the catch per fishing trip almost halved, while the number of trips per vessel doubled. As a result, fuel use intensity (FUI) more than doubled from ∼0.08 to ∼0.18 L fuel per kg mackerel. We estimate that this shift required an additional 23 million liters of fuel per year, causing additional fuel costs of ∼€18 million annually and emitting an additional ∼72,000 tonnes CO 2 per year. The policy change undid ∼15 years of improved fuel efficiency in Norwegian pelagic fisheries. These findings provide rare empirical evidence on how spatial restrictions can undermine progress towards decreasing greenhouse gas emissions in fisheries, highlighting the need to monitor and account for emissions in fisheries management and consider these trade-offs in marine spatial management. [ABSTRACT FROM AUTHOR]

In the face of escalating global climate challenges, effective carbon dioxide (CO₂) capture techniques remain at the forefront of mitigating anthropogenic greenhouse gas emissions. This comprehensive review elucidates the latest advancements in CO₂ capture, emphasizing two predominant methodologies: absorption and adsorption. We delve into the mechanisms underlying each process, highlighting the novel materials and technologies that have emerged over recent years. For absorption, the focus is placed on the material design strategy, and identifying new materials in the class of amines, ionic liquids (ILs) and nanofluids for enhanced CO 2 capture capacities and reduced energy requirements. In the realm of adsorption, the synthesis of innovative adsorbents, such as metal organic framework (MOF), organic polymers, inorganic adsorbents, silicon-based adsorbents, and biochar and byproducts from biomass with superior selectivity and stability, is explored. Additionally, the review addresses the challenges associated with each method, offering insights into potential avenues for further research. By providing a holistic overview of the current landscape of CO₂ capture, this article serves as a pivotal resource for researchers and industry professionals aiming to advance sustainable solutions to combat climate change. [Display omitted] • Absorption and adsorption materials are at the forefront of CO 2 capture technologies. • Ionic-liquids and nanofluids can be comparable to amines with improvements in scalability and stability. • Biomass byproducts as adsorbents offers a sustainable solution to CO 2 capture. [ABSTRACT FROM AUTHOR]

Southeast Asia (SEA) is a key producer and exporter of rice, accounting for around 28% of rice produced globally. To effectively mitigate greenhouse gas (GHG) emissions in SEA rice systems, field methane (CH 4) and nitrous oxide (N 2 O) emissions have been intensively studied. However, an integrated assessment of system-level GHG emissions which includes other carbon (C) balance components, such as soil organic carbon (SOC) or energy use, that can positively or negatively influence the net capacity for climate change mitigation is lacking. We conducted a systematic review of published research in SEA rice systems to synthesize findings across four main components of net system emissions: (1) field GHG emissions, (2) energy inputs, (3) residue utilization beyond the field, and (4) SOC change. The objectives were to highlight effective mitigation opportunities and explore cross-component effects to identify tradeoffs and key knowledge gaps. Field GHG emissions were the largest contributor to net system emissions in agreement with existing scientific consensus, with results showing that practices such as floodwater drainage and residue removal are sound options for CH 4 mitigation. On the other hand, increasing SOC potentially provides a large GHG mitigation opportunity, with long-term continuous rice cropping and practices such as residue incorporation and biochar application promoting SOC increase. A reduction in energy inputs was mainly achieved by optimizing agrochemical use, especially N fertilizers. For residue utilization beyond the field, GHG emission mitigation mainly came from preventing open field burning through residue removal. Removed residue can subsequently be used for producing energy that offsets GHG emissions associated with conventional fuel sources (e.g. fossil fuel-based electricity generation) or substituting material used in other production systems. Integrating all four components of net system emissions into one analysis underscores the following two main takeaways. First, the components of field GHG emissions and SOC change are the biggest opportunities for reducing net system emissions and need to be considered for effective climate change mitigation. Second, the reduction of C inputs through residue removal and increased soil aeration through multiple drainage will lower CH 4 emissions but may also potentially decrease SOC stocks over time. Hence, we argue that future research needs to consider cross-component effects to optimize net system emissions, specifically the "stacking" of best management practices for mitigation related to field GHG emissions or SOC change in long-term experiments. • Net system emissions include field CH 4 /N 2 O emissions, energy inputs, residue utilization, and SOC change. • Integrated review highlights cross-component effects of management including tradeoffs. • Field GHG emissions and SOC change are the largest opportunities for mitigation. • Reduced C inputs and drainage decrease CH 4 emissions, but may negatively affect SOC. • "Stacking" of best management practices is a key knowledge gap that warrants research. [ABSTRACT FROM AUTHOR]

Much recent research on climate change mitigation has focused on carbon intensities, i.e. emissions per unit of economic value, to better understand interrelationships of decarbonization with value. This paper studies large tourism enterprises, which account for a large share of tourism's emissions. Based on annual reports, the paper evaluates greenhouse gas emission and revenue interrelationships for a total of n = 29 large tourism companies including airlines, cruise lines and accommodation businesses. Together, these companies represent about 13% (365 Mt CO 2) of global tourism emissions, generating revenues of US$477 billion (in 2019). The paper tracks their total emissions and emission intensities over the period 2015–2019, revealing that large tourism firms are not on track to net-zero. Results show considerable differences in emission intensities between the three tourism subsectors and between individual firms within the subsectors. These findings are discussed against emission reduction needs to mid-century. There is strong evidence that continued growth at industry's expected rates represents an insurmountable barrier to net-zero, contradicting industry narratives of progressively and successfully engaging with climate change mitigation. [ABSTRACT FROM AUTHOR]

Livestock management is recognized as the largest source of greenhouse gas (GHG) and ammonia emissions in agriculture. Despite the many available mitigation options, they are often not taken up by farmers even when they are economically beneficial for farms. Effective knowledge transfer is among the critical policy instruments to increase the adoption of new mitigating measures. Recently, there has been a shift in agricultural knowledge transfer from a linear, top-down learning model towards more participatory approaches that emphasise peer-to-peer learning. However, effectiveness of the new model has rarely been evaluated. Our study assessed the impact of participatory workshops on farmers' uptake of climate-friendly soil and manure management practices that can help reduce GHG and ammonia emissions. A group of 438 cattle-rearing farmers from two Slovenian regions participated in a randomised experimental evaluation, of which 225 received training and 213 participated in a control group. After attending the participatory workshops, farmers had statistically significant and on average 25% higher knowledge levels of climate change and mitigation measures. Furthermore, the intention to perform mitigation measures was significantly higher, on average by 19%, compared to the control group. The workshops also had a significant positive effect on attitudes towards mitigation measures, climate change beliefs, social norms, psychological distance and perceived behavioural control. However, previous personal experience (habits) had a stronger effect on intentions than participation in workshops. Based on the results we provide recommendations on how to best use various policy tools to increase the adoption of mitigation measures. • We conducted an impact evaluation of participatory workshops' effects on the uptake of climate-friendly farming practices. • The training significantly increased the knowledge and the intention to implement mitigation measures. • Previous experience (habits) had a stronger effect on intentions than workshop participation. • Workshops had positive effects on attitudes, subjective norms and perceived control over adoption of mitigation measures. • Positive attitudes, innovativeness and strong subjective norms positively affected the intention to implement the measures. [ABSTRACT FROM AUTHOR]

Crop residue burning is a common practice in many parts of the world that causes air pollution and greenhouse gas (GHG) emissions. Regenerative practices that return residues to the soil offer a 'no burn' pathway for addressing air pollution while building soil organic carbon (SOC). Nevertheless, GHG emissions in rice-based agricultural systems are complex and difficult to anticipate, particularly in production contexts with highly variable hydrologic conditions. Here we predict long-term net GHG fluxes for four rice residue management strategies in the context of rice-wheat cropping systems in Eastern India: burning, soil incorporation, livestock fodder, and biochar. Estimations were based on a combination of Tier 1, 2, and 3 modelling approaches, including 100-year DNDC simulations across three representative soil hydrologic categories (i.e., dry, median, and wet). Overall, residue burning resulted in total direct GHG fluxes of 2.5, 6.1, and 8.7 Mg CO 2 -e in the dry, median, and wet hydrologic categories, respectively. Relative to emissions from burning (positive values indicate an increase) for the same dry to wet hydrologic categories, soil incorporation resulted in a −0.2, 1.8, or 3.1 Mg CO 2 -e change in emissions whereas use of residues for livestock fodder increased emissions by 2.0, 2.1, or 2.3 Mg CO 2 -e. Biochar reduced emissions relative to burning by 2.9 Mg CO 2 -e in all hydrologic categories. This study showed that the production environment has a controlling effect on methane and, therefore, net GHG balance. For example, wetter sites had 2.8–4.0 times greater CH 4 emissions, on average, than dry sites when rice residues were returned to the soil. To effectively mitigate burning without undermining climate change mitigation goals, our results suggest that geographically-target approaches should be used in the rice-based systems of Eastern India to incentivize the adoption of regenerative 'no burn' residue management practices. • Efforts to build SOC for climate change mitigation, while simultaneously avoiding burning, may have unintended consequences. • Tier 1, 2, and 3 modelling approaches were used to compare no-burn rice residue pathways. • Field hydrology had a dominant effect on methane emissions. • Soil incorporation of residues increased emissions relative to open burning, except in comparatively dry fields. • Biochar is estimated to have the lowest GHG emissions of the evaluated 'no burn' alternatives. [ABSTRACT FROM AUTHOR]

Animal production faces challenges related to thermal comfort, air quality, and carbon dioxide (CO 2) emissions, thereby the need for more efficient and sustainable systems due to climate change. This study examines green roofs and their potential to absorb atmospheric CO 2 and reduce heat load through photosynthesis and evapotranspiration, resulting in decreased energy consumption and increased CO 2 emissions. The maximum CO 2 concentration limit in animal production facilities is 3000 ppm. Depending on the ventilation system used in broiler production facilities, the CO 2 concentration can exceed 2000 ppm. Dark House poultry facilities tend to have higher concentrations reaching up to 777 ppm. In pig farming, the nursery sector has higher concentrations of CO 2 , exceeding 1200 ppm. In dairy farming, the number of milkings, the type of ventilation system and local climatic conditions can affect the CO 2 concentration, reaching values of up to 1401 ppm. C3 plants have a CO 2 saturation point at 800 ppm and C4 plants at 200 ppm. The CO 2 balance in animal production facilities that use a green roof can be done considering the CO 2 produced and the CO 2 absorbed. Green roofs are therefore considered a sustainable solution for animal production. Its implementation enhances air quality in the facilities, supporting the reduction of environmental impacts and mitigation of climate change effects caused by the agroindustry. This investigation underscores the significance of green roofs, emphasizing their environmental, social, and economic benefits, as well as their applicability in animal production. • It is possible to estimate the CO 2 balance in animal production facilities with a green roof. • Green roof can improve air quality in animal production. • Green roof can reduce the thermal stress of the animals in the premises. • Green roof can contribute to the sustainability of animal production. [ABSTRACT FROM AUTHOR]

Tillage practices have major impacts on soil properties, grain yield, soil carbon sequestration, and greenhouse gas emissions. Conservation tillage is an agriculture practice aiming to minimize soil disturbance and protect soil structure. It is reported that more and more croplands are being converted from conventional tillage to conservation tillage in China. However, the information is lacking as to where and when conservation tillage practice is implemented at a regional and national scale. The objectives of this study are 1) to develop a new framework for classifying tillage practices with a random forest model and Google Earth Engine platform to overcome the limitations in mapping tillage practices across China; and 2) to map the spatiotemporal patterns of tillage practices across Chinese croplands from 2016 to 2020. We generated a 1 km grid dataset for tillage practices across Chinese croplands during 2016–2020 based on Sentinel-2 imagery. First, we generated two ground reference sample pools about tillage practices based on literature review and high-resolution maps. Then, we produced Sentinel-2 features during the tillage period by composting 18 bands related to the ratios of returned crop residues. Next, we trained an optimal random forest (RF) classifier by conducting a cross-validation. Finally, we applied the optimal RF classifier to composited features to produce tillage maps from 2016 to 2020. The validation with ground reference samples shows that the classification results have an overall accuracy of 0.80. Comparisons at a provincial scale show the estimated proportion of conservation tillage is significantly correlated with statistic data with R2 being 0.88. Results show that conservation tillage practice is adopted in about 36% of Chinese croplands, mainly distributed in northeast China, northwest China, and the North China Plain. The proportion of conservation tillage ranged from 29% to 40% during 2016–2020 although with a large spatial heterogeneity. This study develops a sound framework to map tillage practices and provides more details about the spatiotemporal patterns of tillage practices, supporting regional planning of agricultural management and climate change mitigation. [ABSTRACT FROM AUTHOR]

• Accelerated systemic decarbonization will become a defining feature of climate action planning. • City CAPs fail to adequately address scope 3 greenhouse gas emissions. • Economic case for climate mitigation at the city level is often weak or missing. • Recent innovations in terms of local climate budgeting are yet to be adopted widely. • Decarbonization pace shaped by political enabling environment and extent of public engagement. Globally, many cities have pledged to reach net zero emissions by mid-century and formulated climate action plans (CAPs) to pursue this goal. Attainment of net zero requires accelerated systemic decarbonization measures to catalyze fundamental changes across multiple societal systems simultaneously. Yet the extant literature has not conceptually clarified conditions leading to accelerated systemic decarbonization in cities. This research therefore aims to: (1) conceptualize strategies that contribute to accelerated systemic decarbonization at the sub-national level and develop a framework for empirically identifying these; and (2) assess the extent to which CAPs in cities known for progressive climate policies embody these characteristics. This involved examination of evidence from CAPs and related documents in six cities: Copenhagen, Leeds, Oslo, San Francisco, Australian Capital Territory and Kyoto. Findings show that San Francisco's climate actions are the most indicative of accelerated systemic decarbonization. In other cities, although many ingredients for accelerated systemic decarbonization are in place, several missed opportunities to achieve more rapid and transformative decarbonization outcomes were identified. These include lack of consideration of scope 3 emissions and limited participatory governance measures as well as absence of economic planning, climate budgets and financial indicators to estimate the benefits or costs of various climate-mitigation actions. [ABSTRACT FROM AUTHOR]