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Since agriculture is a major source of greenhouse gas emissions, accurately calculating these emissions is essential for simultaneously addressing climate change and food security challenges. This paper explores the critical role of trade in transferring agricultural greenhouse gas (AGHG) emissions throughout global agricultural supply chains. We develop a detailed AGHG emission inventory with comprehensive coverage across a wide range of countries and emission sources at first. Utilizing this inventory, the multi-regional input-output analysis is integrated with the complex network analysis to specifically reveal the characteristics of global AGHG flow networks. Finally, scenario analyses reflecting current trends and policy changes in global agriculture are conducted to investigate the emission reduction potential of different networks. The results show that the community division and characteristics of different AGHG networks vary, with more communities in the rice-CH4 and livestock-CH4, N2O networks, and fewer in the cropland-N2O network. Production-side technology improvements (reducing direct carbon emission intensities) and consumption-side livestock products substitution can contribute to the reduction of global AGHG emissions. At the same time, these impacts may propagate to other countries through AGHG networks. In contrast, localization substitution has minimal impact on AGHG emissions and may even result in slight negative effects. It is suggested that enhancing cooperation between countries from a network perspective, such as strengthening the transfer of advanced production technologies within communities, could help reconceptualize global agricultural decarbonization. [ABSTRACT FROM AUTHOR]

Against the backdrop of global warming, the agricultural sector grapples with the dual challenge of safeguarding food security while fulfilling carbon neutrality. Currently, although nitrogen fertilizer and mulch use to enhance maize yields is well-documented, systematic evaluations are lacking in the carbon neutrality potential and holistic benefits, including greenhouse gas (GHG) implications, associated with these strategies. Here, using the calibrated DeNitrification-DeComposition (DNDC) model, we conducted a long-term simulation (1980−2019) incorporating various scenarios of nitrogen fertilizer (N1: conventional nitrogen fertilizer; N0.7: 70% conventional nitrogen fertilizer) and mulch (CK: no-mulch; PM: plastic film mulch; SM: straw mulch), resulting in a baseline scenario (CKN1) and five mitigation scenarios (CKN0.7, PMN1, PMN0.7, SMN1, SMN0.7). We revealed an average net global warming potential during the maize growing season of 5293 kg CO2 eq ha−1, with the most GHG derived from N2O (53%). Considering GHG costs, the net environmental and economic benefits in maize amounted to 5089 CNY ha−1. Presently, Hainan, Henan, Liaoning, and Jilin provinces exhibit a state of low net global warming potential and high net environmental and economic benefits in maize cultivation. Of the mitigation scenarios, only SMN1 concurrently reduced GHG emissions (− 59%) and amplified net environmental and economic benefits (+ 21%) in China. Our results, which provide the first calculation of the combined benefits of mulch and nitrogen fertilizer including GHG costs, not only underscore the immense potential of mulch for enabling carbon neutrality, but also offer valuable insights for policymakers and industry in selecting suitable mulch techniques for agricultural production. [ABSTRACT FROM AUTHOR]

Cattle farming accounts for approximately 15% of Colombia's greenhouse gas emissions (GHGE). Silvopastoral systems (SPS) and improved pastures (IP) are recognized as effective strategies for transforming dairy systems by enhancing cattle productivity, reducing climate change impact, and increasing farm profitability. This study aims to (i) calculate the carbon footprint (CF) of four small dairy cattle farms in the Cauca Department and (ii) identify improvements in milk yields, reductions in GHGE intensities after implementing SPS and IP, and changes in profitability indicators. GHGE were calculated using the 2019 Refinement to 2006 IPCC guidelines and impact factors from databases. Using a cradle-to-farm-gate approach, the functional units were one kg of fat and protein-corrected milk (FPCM) and one kg of live weight gain. A biophysical allocation method was applied to handling co-products leaving the farm. Baseline milk CFs ranged from 2.4 to 3.2 kgCO2–eq kgFPCM−1. In the improvement scenario, the area with SPS and IP covered more than 48% of the total farm area on average. SPS and IP increased the availability and quality of forage, leading to higher animal yields and reducing milk CF by up to 40% (ranging from 1.4 to 2.7 kgCO2–eq kgFPCM−1). These findings provide evidence of the positive impact of adopting IP and SPS on the sustainability of small dairy systems in Colombia by enhancing animal productivity and reducing GHGE intensities. [ABSTRACT FROM AUTHOR]

Mitigating methane (CH4) emissions from China's coal mines as the largest contributor to anthropogenic CH4 emissions is vital for limiting global warming. However, the knowledge about CH4 mitigation potentials and economic costs of Chinese coal mines remain poorly understood, which hinders the formulation of tailored CH4 mitigation strategies. Here, we estimate and project China's provincial coal mine methane (CMM) emissions, mitigation potentials and costs under various coal production scenarios, by integrating the dynamic emission factors of CMM and key abatement technologies. We find that through continuous coal cuts and available CMM mitigation measures, China's CMM emissions can be reduced by 65%-78% (10.9 Tg-13.1 Tg) in 2060, compared with the 2021 level. CH4 emissions from abandoned coal mines will far exceed those from coal mining under the 2060 carbon-neutral scenario, especially in northeastern China. It was also found that CMM mitigation is not economically feasible at present, but may be the most cost-effective solution as CO2 prices increase. All coalproducing provinces can achieve CMM mitigation below 50 RMB/t CO2 e in 2060. Inner Mongolia is identified as a hotspot for CMM mitigation with huge potential and lower cost. Our prospective assessment can provide insights into China's CMM mitigation in response to climate change. [ABSTRACT FROM AUTHOR]

Abstract Household consumption accounts for 65–72% of total greenhouse gas emissions globally, and therefore, a change in current consumption patterns has the potential to mitigate climate change and provide emission reductions. There is knowledge on the consumption options with a high mitigation potential, but this information has not been combined with a consumer behavior information. This study examines the emission-reduction potential of suburban residents in Finland through a survey that assesses their willingness to adopt climate actions, and by calculating the potential impact of various actions. Finnish suburban households have already implemented low-impact climate actions (recycling, reducing food waste), but the implementation of high-impact actions in households could also be increased. Transitioning to a vegetarian diet, reducing air travel and limiting consumption are identified as the most effective mitigation actions when the potential increase in the implementation rate and impact on greenhouse gas emissions are considered. However, the results suggest that voluntary individual efforts alone are not sufficient to achieve the 1.5 °C carbon budget. Thus, alongside behavioural changes, strong policy measures and technological advancements are necessary. These findings emphasise the specific individual actions that should be prioritised when formulating climate policies at the national or city levels.

Household consumption accounts for 65–72% of total greenhouse gas emissions globally, and therefore, a change in current consumption patterns has the potential to mitigate climate change and provide emission reductions. There is knowledge on the consumption options with a high mitigation potential, but this information has not been combined with a consumer behavior information. This study examines the emission-reduction potential of suburban residents in Finland through a survey that assesses their willingness to adopt climate actions, and by calculating the potential impact of various actions. Finnish suburban households have already implemented low-impact climate actions (recycling, reducing food waste), but the implementation of high-impact actions in households could also be increased. Transitioning to a vegetarian diet, reducing air travel and limiting consumption are identified as the most effective mitigation actions when the potential increase in the implementation rate and impact on greenhouse gas emissions are considered. However, the results suggest that voluntary individual efforts alone are not sufficient to achieve the 1.5 °C carbon budget. Thus, alongside behavioural changes, strong policy measures and technological advancements are necessary. These findings emphasise the specific individual actions that should be prioritised when formulating climate policies at the national or city levels. [ABSTRACT FROM AUTHOR]

Cattle farming is responsible for about 15% of Colombia's greenhouse gas emissions (GHGE). In the department of Cundinamarca, specialized dairy farms located in the high tropics contribute 14% of the national milk production, and 94% of them are small-scale producers. Therefore, mitigation strategies for dairy farms are needed to achieve national GHGE reduction targets. This study aims to quantify the carbon footprint (CF), through a Life cycle Assessment Methodology, of 82 specialized dairy farms at the farm gate in 3 regions of Cundinamarca: Central Savannah, West Savannah and Ubate Valley; and to identify the contribution of Acacia decurrens, Baccharis latifolia, and Sambucus peruviana to milk production increases and GHGE mitigation potential. The comparison of the effect of the tree species on the measured variables was carried out by analysis of variance under a completely random design. GHGE were calculated using the 2019 Refinement to 2006 IPCC guidelines and impact factors from databases. The emission factor for enteric methane from cows was estimated by considering the equation proposed by Niu et al. (Glob Chang Biol 24:3368–3389, 2018). The functional units corresponded to one kg fat and protein-corrected milk (FPCM) and one kg live weight gain in a cradle-to-farm-gate approach. For the 3 regions, enteric fermentation and manure left on pasture were the main on-farm sources of GHGE, and feed manufacturing was the main off-farm source. Milk CFs ranged from 1.5 to 2.2 kg CO2-eq kg FPCM−1. The inclusion Acacia decurrens, Baccharis latifolia, and Sambucus peruviana in cattle diets reduced the milk CF by 13–26% and increased milk yield by 19–37% in the three regions. Therefore, the inclusion of locally available forages in dairy cattle diets is a potential sustainable GHGE mitigation option that dairy farmers, from the Colombian high tropics, can adopt. [ABSTRACT FROM AUTHOR]

Abstract Biochar has gained significant attention in agricultural and environmental research over the last two decades. This comprehensive review evaluates the effects of biochar on soil organic carbon (SOC), emission of non-CO2 greenhouse gases, and crop yield, including related mechanisms and major influencing factors. The impacts of biochar on SOC, methane and nitrous oxide emissions, and crop yield are controlled by biochar and soil properties and management practices. High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure. In contrast, low-temperature biochar from manure may increase crop yield in low-fertility soils. Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO2-eq year−1, respectively, while increasing crop yields by 19%. Despite the increasing evidence of the positive effects of biochar, future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production. We conclude that biochar is not a universal solution for global cropland; however, targeted applications in fields, landscapes, or regional scales, especially in low fertility and sandy soils, could realize the benefits of biochar as a climate-smart measure. Highlights The findings of research on biochar's effects on soil C sequestration, GHG mitigation, and crop production were summarized. The factors influencing the impact of biochar on soil functioning were reviewed. The effects of biochar on soil C sequestration and GHG mitigation in farmlands of China were quantified. Graphical Abstract

Abstract Meeting climate change mitigation targets by 2050, as outlined in international pledges, involves determining optimal strategies for forest management, wood supply, the substitution of greenhouse gas‐intensive materials and energy sources, and wood product disposal. Our study quantified the cumulative mitigation potential by 2050 of the forest sector in the province of Quebec, Canada, using several alternative strategies and assessed under what circumstances the sector could contribute to the targets. We used the Carbon Budget Model of the Canadian Forest Sector to project ecosystems emissions and sequestration of seven alternative and one baseline (business‐as‐usual [BaU]) forest management scenarios over the 2018–2050 period. Three baskets of wood products were used in a Harvested Wood Products model to predict wood product emissions. The mitigation potential was determined by comparing the cumulative CO2e budget of each alternative scenario to the BaU. The proportion of methane emissions from landfills (RCH4%) and the required displacement factor (RDF) to achieve mitigation benefits were assessed both independently and jointly. The fastest and most efficient way to improve mitigation outcomes of the forest sector of Quebec is to reduce end‐of‐life methane emissions from wood products. By reducing methane emissions, the RDF for achieving mitigation benefits through intensification strategies can be reduced from 1.2–2.3 to 0–0.9 tC/tC, thus reaching the current provincial mean DF threshold (0.9). Both a reduction and an increase in the harvested volume have the potential to provide mitigation benefits with adequate RCH4% and RDF. Increased carbon sequestration in ecosystems, innovations in long‐lived wood products, and optimal substitution in markets offer potential avenues for the forest sector to contribute to mitigation benefits but are subject to significant uncertainties. Methane emission reduction at the end of wood product service life is emerging as a valuable approach to enhance mitigation benefits of the forest sector.

Aviation contributes about 4 % of global anthropogenic climate forcing primarily by contrails, CO2 and NOx emissions. Renewably sourced aviation kerosene can help to reduce the climate impact from CO2 and from contrails, but so far, its production capacities are very small. Hence, the climate impact of using fossil fuel-based kerosene with a hydrogen content increased by hydroprocessing as short term mitigation measure is studied here. Therefore, the change in net energy forcing (ΔEFnet) in 2019 is calculated as the sum of the change in contrail energy forcing (ΔEFcontrail) and additional CO2 emissions (ΔEFhydroprocessing) from aviation kerosene hydroprocessing (ΔEFnet = ΔEFcontrail + ΔEFhydroprocessing). The results show that hydroprocessed aviation kerosene can reduce the net energy forcing EFnet by about 33 % with ΔEFhydroprocessing penalty of 5 %-points. Increasing the hydroprocessing severity increases the relative climate benefit, which is only slightly affected by the emissions factor for hydroprocessing or the choice of the time horizon. Data limitations about fuel composition and its effect on contrails and climate cause considerable uncertainties and the fuel's compliance with specification standards needs consideration. This study on the climate effect of hydroprocessed fossil kerosene can help to assess near-term measures to reduce the climate impact from aviation.

Biochar has gained significant attention in agricultural and environmental research over the last two decades. This comprehensive review evaluates the effects of biochar on soil organic carbon (SOC), emission of non-CO2 greenhouse gases, and crop yield, including related mechanisms and major influencing factors. The impacts of biochar on SOC, methane and nitrous oxide emissions, and crop yield are controlled by biochar and soil properties and management practices. High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure. In contrast, low-temperature biochar from manure may increase crop yield in low-fertility soils. Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO2-eq year−1, respectively, while increasing crop yields by 19%. Despite the increasing evidence of the positive effects of biochar, future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production. We conclude that biochar is not a universal solution for global cropland; however, targeted applications in fields, landscapes, or regional scales, especially in low fertility and sandy soils, could realize the benefits of biochar as a climate-smart measure. Highlights The findings of research on biochar's effects on soil C sequestration, GHG mitigation, and crop production were summarized. The factors influencing the impact of biochar on soil functioning were reviewed. The effects of biochar on soil C sequestration and GHG mitigation in farmlands of China were quantified. [ABSTRACT FROM AUTHOR]

Meeting climate change mitigation targets by 2050, as outlined in international pledges, involves determining optimal strategies for forest management, wood supply, the substitution of greenhouse gas‐intensive materials and energy sources, and wood product disposal. Our study quantified the cumulative mitigation potential by 2050 of the forest sector in the province of Quebec, Canada, using several alternative strategies and assessed under what circumstances the sector could contribute to the targets. We used the Carbon Budget Model of the Canadian Forest Sector to project ecosystems emissions and sequestration of seven alternative and one baseline (business‐as‐usual [BaU]) forest management scenarios over the 2018–2050 period. Three baskets of wood products were used in a Harvested Wood Products model to predict wood product emissions. The mitigation potential was determined by comparing the cumulative CO2e budget of each alternative scenario to the BaU. The proportion of methane emissions from landfills (RCH4%) and the required displacement factor (RDF) to achieve mitigation benefits were assessed both independently and jointly. The fastest and most efficient way to improve mitigation outcomes of the forest sector of Quebec is to reduce end‐of‐life methane emissions from wood products. By reducing methane emissions, the RDF for achieving mitigation benefits through intensification strategies can be reduced from 1.2–2.3 to 0–0.9 tC/tC, thus reaching the current provincial mean DF threshold (0.9). Both a reduction and an increase in the harvested volume have the potential to provide mitigation benefits with adequate RCH4% and RDF. Increased carbon sequestration in ecosystems, innovations in long‐lived wood products, and optimal substitution in markets offer potential avenues for the forest sector to contribute to mitigation benefits but are subject to significant uncertainties. Methane emission reduction at the end of wood product service life is emerging as a valuable approach to enhance mitigation benefits of the forest sector. We determined the Quebec forest sector's carbon mitigation potential using alternative strategies (forest ecosystems/product decay/substitution). We estimated the displacement factors that are required for wood products by 2050. We estimated the landfill CH4 emission reductions that must be achieved by 2050. Conservation alternatives increase carbon sinks by 2050, and intensification alternatives increase carbon sources by 2050. With improved methane management and optimal substitution, both conservation and intensification scenarios could provide mitigation benefits. Quebec's forests sector can contribute to enhanced climate mitigation benefits if sustainable forest management, optimum use of wood, and improved methane management of landfills are achieved. [ABSTRACT FROM AUTHOR]

The contribution of the forest sector to climate change mitigation needs to rely on optimal strategies that include forest management, wood supply, wood product disposal, and replacement of GHG-intensive materials and energy sources. Our study aimed to assess the impact of alternative forest management practices applied at the stand scale on the capacity of the forest sector to reduce its radiative forcing, using the boreal forests of eastern Canada as a case study. We simulated management of a balsam fir–white birch stand over a sixty-year period and determined the sectorial carbon and radiative forcing budget for a reference scenario (no harvest) and for nineteen clearcut and partial cut alternatives. The results suggest that logging may not significantly reduce carbon emissions compared to a preservation practice and does not yield any climate benefits in terms of radiative forcing. In a context for which the substitution effect of wood products on markets is expected to be limited, the mitigation potential of a scenario is mostly driven by the capacity of the forest ecosystem carbon sink to compensate for the substantial CO 2 and CH 4 emissions from wood product decay in landfills. The improved assessment of carbon emission temporality, incorporation of ecosystem carbon dynamics, and improved consideration of substitution and the decay of wood products are essential in the development of any forest management strategy. Neglecting these elements can lead to misconceptions and prevent informed mitigation decisions. [ABSTRACT FROM AUTHOR]

Resumption of the increase in atmospheric methane (CH4) concentrations since 2007 is of global concern and may partly have resulted from emissions from rice cultivation. Estimates of CH4 emissions from rice fields and abatement potential are essential to assess the contribution of improved rice management in achieving the targets of the Global Methane Pledge agreed upon by over 100 countries at COP26. However, the contribution of CH4 emissions from rice fields to the resumed CH4 growth and the global abatement potential remains unclear. In this study, we estimated the global CH4 emissions from rice fields to be 27 ± 6 Tg CH4 year-1 in the recent decade (2008-2017) based on the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. The trend of CH4 emissions from rice cultivation showed an increase followed by no significant change and then, a stabilization over 1990-2020. Consequently, the contribution of CH4 emissions from rice fields to the renewed increase in atmospheric CH4 concentrations since 2007 was minor. We summarized the existing low-cost measures and showed that improved water and straw management could reduce one-third of global CH4 emissions from rice fields. Straw returned as biochar could reduce CH4 emissions by 12 Tg CH4 year-1, equivalent to 10% of the total reduction of all anthropogenic emissions. We conclude that other sectors than rice cultivation must have contributed to the renewed increase in atmospheric CH4 concentrations, and that optimizing multiple mitigation measures in rice fields could contribute significantly to the abatement goal outlined in the Global Methane Pledge. [ABSTRACT FROM AUTHOR]

Global warming has driven the expansion of cultivated land to high-altitude areas. Intensive vegetable production, which is generally considered to be a high economic value and high environmental risk system, has expanded greatly in high-altitude mountainous areas of China. However, the environmental cost of vegetable production in these areas is poorly understood. In this study, pepper production at low (traditional pepper production area) and high (newly expanded area) altitudes were investigated in Shizhu, a typical pepper crop area. The output and environmental cost at the two altitudes were identified. the influence of resource inputs, climate, and soil properties on pepper production was evaluated. There were obvious differences in output and environmental cost between the two altitudes. High-altitude pepper production achieved a 16.2% lower yield, and had a higher fertilizer input, resulting in a 22.3% lower net ecosystem economic benefit (NEEB), 23.0% higher nitrogen (N) footprint and 24.0% higher carbon (C) footprint compared to low-altitude farming. There is potential for environmental mitigation with both high- and low-altitude pepper production; Compared to average farmers, high-yield farmers groups reduced their N and C footprints by 16.9–24.8% and 18.3–25.2%, respectively, with 30.6–34.1% higher yield. A large increase in yield could also be achieved by increasing the top-dress fertilizer rate and decreasing the plant density. Importantly, high-altitude pepper production was achieved despite less advanced technology and inferior conditions (e.g., a poor road system and uneven fields). It provides a reference for the study of the environmental cost of other high-altitude regions or other crop systems at high-altitude areas. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensis L.), the most popular beverage worldwide and an important cash crop in China, plays a crucial role in the socio-economic landscape. Reactive nitrogen (Nr) loss from tea cultivation in China has become a major environmental problem due to the high input of N fertilizers. However, the scale of the Nr loss and its environmental impact on tea production in China remains unknown. Hence, we conducted a comprehensive meta-analysis of ammonia volatilization (NH 3), nitrogen oxide (NO x), nitrous oxide (N 2 O) emissions, N leaching (total nitrogen, TN), and N runoff (TN) losses in tea plantations in China. The total Nr loss in Chinese tea plantations was 376 Gg yr−1 (149 kg N ha−1 yr−1) in 2014, with N leaching, NH 3 volatilization, N 2 O emissions, NO x emissions, and N runoff losses accounting for 52.2 %, 33.2 %, 7.5 %, 5.4 %, and 1.7 %, respectively. The total Nr loss-related environmental damage cost of tea cultivation reached 9.53 billion CNY yr−1 in 2014, which was 7.7 % of the total tea production output value. The bulk of the environmental damage cost was attributed to NH 3 volatilization (49.1 %), N 2 O emissions (24.9 %), and N leaching (19.2 %). Large Nr losses occurred during tea production in Sichuan, Hubei, Guizhou, Yunnan, Zhejiang, and Hunan provinces, accounting for 17.7 %, 17.0 %, 13.4 %, 10.7 %, 7.6 %, and 7.0 % of the total Nr losses in China, respectively. Our analysis showed that the adoption of integrated nutrient management reduced N fertilizer inputs to 300 kg N ha−1, lowered Nr loss from 376 Gg to 172 Gg yr−1, and reduced the environmental damage cost of N loss by 45.4 %. These findings, along with detailed data on the N balance of tea cultivation, provides critical information needed to develop effective region-specific N nutrient management practices and policies for sustainable and profitable tea crop production in China, and possibly in other similar geographies. [Display omitted] • We quantified the annual reactive nitrogen (Nr) losses from tea plantations in China. • Nitrogen leaching and ammonia volatilization are the major pathways of Nr losses. • The Nr losses associated environmental cost in tea cultivation accounts to 7.7 % of the output value. • Significant variations in Nr losses and consequent damage costs were observed across different tea-growing regions in China. [ABSTRACT FROM AUTHOR]

This paper aims to study the decoupling status and emission reduction potential of China's petrochemical industry from 1996 to 2019. Firstly, the IPCC method is used to calculate the CO2 emissions of the petrochemical industry in China, then the logarithmic mean Divisia index (LMDI) method is used to identify the influencing factors of CO2 emissions, then the decoupling index is constructed to analyze the dependence of economic development on CO2 emissions, and finally the emission reduction potential model is established by using the influencing factors to reflect the CO2 emission reduction potential of the petrochemical industry. The results reveal that (1) the CO2 emissions can be divided into two stages of slow decline (1996–2000), (2015–2019), and one stage of rapid growth (2000–2015). (2) The energy intensity effect is the most effective factor to restrain CO2 emission, the economic growth effect is the key factor to promote CO2 emission. (3) From 1996 to 2019, there was a weak decoupling relationship between CO2 emission of petrochemical industry and economic development. Strong decoupling only occurred in 1996–2000 and 2015–2019. The CO2 emissions show only three decoupling score: I, II, and III. (4) CO2 mitigation occurred in four sub periods: 1996–2000, 2005–2010, 2010–2015, and 2015–2019. Therefore, the government should establish an energy-saving and environment-friendly industrial production system, intensify the use of clean energy, and optimize the labor force structure. It not only effectively strengthens the decoupling between the petrochemical industry and economic development, but also provides an empirical example for the carbon emission reduction and economic sustainable development of the petrochemical industry in other countries in the world. [ABSTRACT FROM AUTHOR]

Landfilling of solid waste has been and continues to be among the most common practices of solid waste disposal. This is particularly true for Jordan, where approximately 3.3 million tons of municipal solid waste (MSW) is annually generated, with 90% of the generated amount disposed into landfills. The main objective of this study is to estimate the quantities of landfill gas (LFG) generated from the solid waste disposal and its potential as a source of clean energy in Jordan using four different models, namely, GasSim 2.5, LandGEM, Afvalzorg, and Mexico Landfill Gas Model V2 (MLFGM V2). Furthermore, the greenhouse gas (GHG) mitigation potential of LFG projects was estimated. Currently, there are 18 active landfills that are distributed across the country. Based on screening criteria, the landfills were grouped into three categories: five landfills were considered for energy production, four were strong candidates for LFG collection and flaring, while the remaining nine landfills do not receive enough waste to be considered for either energy recovery or flaring. The total amount of LFG emissions was found to be 1.6 billion M3 of LFG, while the landfill energetic potential of the recovered LFG was estimated to be 34.8 MW. On the other hand, GHG mitigation potential was assessed between the years 2020 and 2030, which was found to be 18 million ton CO2 eq. The proposed LFG energy recovery projects will lead to increased biogas contribution to Jordan's local renewable energy mix from a current level of 1% to 6%. [ABSTRACT FROM AUTHOR]

Cladding components are critical when designing a building to resist blast loads, as they are the first to receive the applied airblast pressure. A recent trend is to design them in order to reduce the blast pressure transferred to the supporting structure, thus minimizing the overall load demand and consequences to the building frame. Therefore, it is desirable to develop a generally applicable method for evaluating the cladding performance in terms of blast pressure mitigation. In the present study, a methodology for calculating this mitigation potential is proposed, employing the dynamic load factor (DLF) of a dimensionless single-degree-of-freedom (SDOF) model subjected to blast for a variety of pressure and impulse combinations. The DLF of multiple SDOF analyses is used to calculate an overall indicator for the mitigation potential of the corresponding cladding. To further demonstrate the proposed methodology, four steel cladding types are analyzed, and their mitigation potential is mapped into their pressure–impulse diagrams. Furthermore, the effects of the activated mechanisms of plastic energy absorption and inertial resistance are presented through performance observations for the different geometry and boundary configurations of the four cladding types. Among the four cladding types, the best-and worst-performing ones were found to be a thick and a thin monolithic plate, respectively, while the performance of sandwich-type panels was in between. Generally, the analysis results suggest that the increased mass and plastic dissipation in the cladding are beneficial for the building frame, while increased stiffness may overload the building frame. [ABSTRACT FROM AUTHOR]

In the current era of global warming, the Himalayan forests are under tremendous pressure due to intensified anthropogenic activity, resulting in the loss of forest diversity. However, the potential of carbon (C) sinks for increasing carbon storage and/or sequestration is still uncertain. Therefore, the present study was undertaken to examine the C‐sequestration and mitigation potential of eight different tree plantations, namely: Pinus roxburghii, Quercus leucotrichophora, Acacia mollissima, Acacia catechu, Alnus nitida, Albizia procera, Ulmus villosa, and Eucalyptus tereticornis in the mid‐hills of the Indian Himalayas. The soil samples used in our study (humus, 0–20cm, 20–40cm, and 40–100 cm) were used to determine the soil and ecosystem C‐density. The analysis revealed that the maximum tree biomass (300.19 Mg ha−1), vegetation biomass (305.43 Mg ha−1), vegetation carbon (153.59 Mg ha−1), and total ecosystem C density (369.93 Mg ha−1) occurred under U. villosa plantation. Similarly, P. roxburghii plantations had the maximum detritus C‐density (7.25 Mg ha−1), whereas A. nitida (224.71 Mg ha−1) had the maximum soil C‐density. The highest C‐sequestration was recorded under U. villosa (183.0 Mg ha−1). A significantly higher and lower rate of C‐sequestration and CO2 mitigation was observed in Ulmus villosa (5.9 and 21.64 Mg ha−1 yr−1) and Eucalyptus tereticornis (3.9 and 14.3 Mg ha−1 yr−1). Our study found that indigenous tree species such as U. villosa, A. procera, A. nitida, and Q. leucotrichophora should be encouraged for afforestation on degraded lands to support climate change mitigation strategies in the sub‐temperate forest ecosystem. [ABSTRACT FROM AUTHOR]

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Ammonia is the only alkaline gas in the atmosphere. Reducing ammonia emissions plays an important role in controlling atmospheric pollution. Livestock and poultry breeding industry is an important source of ammonia emissions. Scientific assessment of ammonia emissions and reduction potential in different links is of great significance. In this paper, the ammonia emission factors of different livestock and poultry breeding houses in China and abroad, the main emission reduction technologies and efficiency were summarized. Combined with the number of mechanical ventilation farms and the animal population of major livestock and poultry obtained from the second national pollution source census, the ammonia emission reduction potential of exhaust air from mechanical ventilation livestock farms in China was analyzed. The results show that the reduction potential of ammonia emission from mechanically ventilated livestock houses in China is 265.6 thousand tons; pigs, laying hens and broilers were the three main sources of livestock and poultry, and their emission reduction potential were 101.8 thousand tons, 77.3 thousand tons and 67.5 thousand tons, respectively. The emission reduction potential of the three livestock and poultry types accounted for 92.8 %. Regionally, the main implementing regions are East China, South Central and North China, with ammonia emission reduction potential accounting for 35.1%, 26.9% and 14.9%, respectively. It is proposed to carry out the construction of ammonia emission reduction facilities in mechanical ventilation barn of pig, laying hens and broiler, which can provide guarantee for the national ammonia emission reduction and the improvement of atmospheric environmental quality. [ABSTRACT FROM AUTHOR]

Although hybrid maize seed production is one of the most important agriculture systems worldwide, its greenhouse gas (GHG) emissions and potential mitigation measures have not been studied. In this study, we used life cycle assessment (LCA) to quantify the GHG emissions of 150 farmers run by 6 companies in an area of northwest China known for hybrid maize seed production. The results indicated that the average reactive nitrogen (Nr) losses and GHG emissions from hybrid maize seed production were 53 kg N ha−1 and 8077 kg CO2 eq ha−1, respectively. Furthermore, the average nitrogen and carbon footprints of the process were 12.2 kg N Mg−1 and 1495 kg CO2 eq Mg−1, respectively. Nitrogen fertilizer and electricity consumption for irrigation were the main contributors to high GHG emissions, accounting for 60% and 30% of the total, respectively. The GHG emissions from seed production for different companies varied greatly with their resource input. There was also a large variation in environmental burdens among the 150 farmers. Based on an analysis of the yield group, we found that the carbon footprint of the first group (the one with the highest yield) was 27% lower than the overall average. Scenario analysis suggests that a combined reduction of N input rate, optimizing irrigation, and increasing yield can eventually mitigate the carbon footprint of hybrid maize seed production by 37%. An integrated systematic approach (e.g., ISSM: integrated soil-crop system management) can reduce the GHG emissions involved in producing hybrid maize seeds. This study provides quantitative evidence and a potential strategy for GHG emissions reduction of hybrid maize seed production. [ABSTRACT FROM AUTHOR]

In order to quantify the contribution of the mitigation strategies, an extended Kaya identity has been proposed in this paper for decomposing the various factors that influence the CO2 emission. To this end, we provided a detailed decomposition of the carbon intensity and energy intensity, which enables the quantification of clean energy development and electrification. The logarithmic mean divisia index (LMDI) has been applied to the historical data to quantify the contributions of the various factors affecting the CO2 emissions. Further, the global energy interconnection (GEI) scenario has been introduced for providing a systematic solution to meet the 2°C goal of the Paris Agreement. By combining LMDI with the scenario analysis, the mitigation potential of the various factors for CO2 emission has been analyzed. Results from the historical data indicate that economic development and population growth contribute the most to the increase in CO2 emissions, whereas improvement in the power generation efficiency predominantly helps in emission reduction. A numerical analysis, performed for obtaining the projected future carbon emissions, suggests that clean energy development and electrification are the top two factors that can decrease CO2 emissions, thus showing their great potential for mitigation in the future. Moreover, the carbon capture and storage technology serves as an important supplementary mitigation method.

Global warming has driven the expansion of cultivated land to high-altitude areas. Intensive vegetable production, which is generally considered to be a high economic value and high environmental risk system, has expanded greatly in high-altitude mountainous areas of China. However, the environmental cost of vegetable production in these areas is poorly understood. In this study, pepper production at low (traditional pepper production area) and high (newly expanded area) altitudes were investigated in Shizhu, a typical pepper crop area. The output and environmental cost at the two altitudes were identified. the influence of resource inputs, climate, and soil properties on pepper production was evaluated. There were obvious differences in output and environmental cost between the two altitudes. High-altitude pepper production achieved a 16.2% lower yield, and had a higher fertilizer input, resulting in a 22.3% lower net ecosystem economic benefit (NEEB), 23.0% higher nitrogen (N) footprint and 24.0% higher carbon (C) footprint compared to low-altitude farming. There is potential for environmental mitigation with both high- and low-altitude pepper production; Compared to average farmers, high-yield farmers groups reduced their N and C footprints by 16.9–24.8% and 18.3–25.2%, respectively, with 30.6–34.1% higher yield. A large increase in yield could also be achieved by increasing the top-dress fertilizer rate and decreasing the plant density. Importantly, high-altitude pepper production was achieved despite less advanced technology and inferior conditions (e.g., a poor road system and uneven fields). It provides a reference for the study of the environmental cost of other high-altitude regions or other crop systems at high-altitude areas.

This article evaluates and compares the enviro-economic potential of two distinctly (parallel flow and serpentine flow) fabricated PV/T water heating systems in view of their respective thermal optimization. A one-dimensional steady-state heat transfer model along with the concept of least entropy production yields around 20 lh−1 being the optimal flow which corresponds to highest thermal exergy of 1.5 and 1.8% for the two systems under consideration. The modeling results reveal an appreciable validation with the experimental data which correspond to maximum increment in DC power by 17.7 and 19.3 W complimented by their low-grade water heating applications worth 493.5 and 530.8 W, respectively. The mitigation potential of both the systems is well appreciated through certain pre-defined parameters as an outcome of the economic modeling. An additional 35–40% increment in total efficiency corresponds to almost 7–8% gain in electrical power with respective (parallel and serpentine) thermal configurations. Both the systems unanimously contribute 15 and 18% increment in their respective exergy-based mitigation potential as compared against 85 and 97% increment in energy-based enviro-economic parameter with respect to solo PV installation. Exergy-based performance indices show smaller increment with respect to energy-based EPI for both the designs, while energy payback period of the serpentine-based thermal installation falls 3 years shorter than a standard 255-W reference PV module. [ABSTRACT FROM AUTHOR]

Background Forest based climate mitigation emerged as a key component of the Paris Agreement, and thus requires robust science to reduce uncertainties related to such strategies. The aim of this study was to assess and compare the cumulative effects on carbon dynamics of forest management and climate change on boreal and northern temperate forest sector in eastern Canada for the 2020–2100 period. Methods We used the spatially explicit forest landscape model LANDIS-II and its extension Forest Carbon Succession, in conjunction with the Carbon Budget Model for Harvested Wood Products framework. We simulated the dynamics of forest composition and carbon flows from forest ecosystems to wood products and their substitution effect on markets under increasing climate forcing, according to a tonne-year approach. Simulations were conducted for a series of forest management scenarios based on realistic practices principally by clearcut in the boreal territory and continuous-cover forestry in the northern temperate one. These scenarios included: i) a business-as-usual scenario (BaU), representing the current management strategy, ii) increased harvesting by 6.3% to 13.9%, iii) increased conservation (i.e. reduced harvesting by 11.1% to 49.8%), iiii) and a scenario representing the natural evolution of the forest landscape (i.e. without any management activity). Results Our study revealed that increasing harvesting levels had contrasting effects on the mitigation potential in northern temperate (enhance net sequestration) and boreal forest sector (enhance net emissions) in comparison to the BaU from 2040 onwards, regardless of the future climate. Carbon storage in wood products and the substitution effect were not sufficient to offset carbon emissions from ecosystems. Moreover, climate change had a strong impact on the capacity of both landscapes to act as carbon sinks. Northern temperate landscapes became a net source of carbon over time due to their greater vulnerability to climate change than boreal landscapes. Conclusions Our study highlights the need to consider the initial landscape characteristics in simulations to maximize the mitigation potential of alternative forest management strategies. The optimal management solution can be very different according to the characteristics of forest ecosystems. This opens the possibility of optimizing management for specific forest stands, with the objective of maximizing the mitigation potential of a given landscape. [ABSTRACT FROM AUTHOR]

Flooded rice fields have been confirmed as a major anthropogenic source of atmospheric methane (CH4). Avoiding continuous flooding is an effective practice to mitigate the CH4 emissions originating from paddy fields. However, the contradiction between the high yield and water consumption of paddy rice limits the mitigation potential of greenhouse gas (GHG) emissions through a dramatic reduction in water usage. Recently, a new rice type, water-saving and drought-resistance rice (WDR), has been developed to satisfy both the rice yield and quality with a high water use efficiency and good drought resistance. WDR can be planted under dry cultivation, similar to upland crops. A biogeochemical process model, DNDC (i.e., DeNitrification-DeComposition) was used to evaluate the effect of agricultural practices (F-R as paddy rice under flooding management and D-WDR as WDR under dry cultivation) on GHG emissions from paddy fields in Anhui Province, China. The results are as follows: 1) the DNDC model attained a good performance when simulating the rice yield, seasonal cumulative CH4 and N2O emissions, and GWP; 2) the mitigation potential of the D-WDR system was higher than 90% while maintaining a high rice yield; 3) if rice paddies in Anhui can be replaced by D-WDR system, the GHG mitigation potential could reach 16.92 Mt CO2-eq, and the increased N2O emissions of the WDR system could offset a small fraction (7.6%) of the GHG radiated forcing benefit gained by the decrease in CH4 emissions. Shifting rice production from paddy rice to WDR has a remarkable potential to balance the relationship between CH4 mitigation and rice yield maintenance. [ABSTRACT FROM AUTHOR]

Rice is an important global crop while also contributing significant anthropogenic methane (CH _4 ) emissions. To support the future of rice production, more information is needed on the impacts of sustainability-driven management used to grow rice with lower associated methane emissions. Recent support for the impacts of different growing practices in the US has prompted the application of a regional methodology (Tier 2) to estimate methane emissions in different rice growing regions. The methodology estimates rice methane emissions from the US Mid-South (MdS) and California (Cal) using region-specific scaling factors applied to a region-specific baseline flux. In our study, we leverage land cover data and soil clay content to estimate methane emissions using this approach, while also examining how changes in common production practices can affect overall emissions in the US. Our results indicated US rice cultivation produced between 0.32 and 0.45 Tg CH _4 annually, which were approximately 7% and 42% lower on average compared to Food and Agriculture Organization of the UN (FAO) and US Environmental Protection Agency (EPA) inventories, respectively. Our estimates were 63% greater on average compared to similar methods that lack regional context. Introducing aeration events into irrigation resulted in the greatest methane reductions across both regions. When accounting for differences between baseline and reduction scenarios, the US MdS typically had higher mitigation potential compared to Cal. The differences in cumulative mitigation potential across the 2008–2020 period were likely driven by lower production area clay content for the US MdS compared to Cal. The added spatial representation in the Tier 2 approach is useful in surveying how impactful methane-reducing practices might be within and across regions.

Mountain vegetable production has become a critical source of low heat-resistance vegetables in summer in subtropical regions, but evaluations based on life-cycle assessment (LCA) that are relevant to the environment and economics have not been reported. We conducted a survey to compare the cabbage yield and resource inputs for small-holder farms at a high (HEL, 900–1500 m) and low (LEL, 200–600 m) elevations in a subtropical region in Southwest China. We used LCA to quantify the nitrogen (N) and carbon (C) footprints, and used the yield and environmental impacts gap method to determine the potential to mitigate the environmental impacts of farming at HELs and LELs. The results show that the respective average reactive N (Nr) and greenhouse gas (GHG) emissions for the HEL and LEL were 137.0 kg N ha−1 and 6785 kg CO2-eq ha−1, and 126.7 kg N ha−1 and 6153 kg CO2-eq ha−1, respectively. The N and C footprints for the HEL were 17.3% and 16.2% lower, respectively, than those for the LEL due to the higher yield at the HEL. The average cabbage yield was 26.5% greater at the HEL (53.2 t ha−1) than at the LEL (42.0 t ha−1). The average total N application rate at the HEL was 455 kg N ha−1, which was 6.0% greater than that at the LEL. There was great potential for yield increases and the mitigation of N and C footprints by farmers at both the HEL and LEL. Compared to the average of all surveyed farmers for HEL and LEL, those farmers whose yields and N fertilizer production efficiency were both higher than the average of all surveyed farmers (HH groups) reduced their N and C footprints by 44.7–49.4% and 44.4–51.2%, respectively, with 34.4–52.3% higher yield and 9.2–19.8% lower N application rate. This study indicates that high yield, low environmental cost, and high economic benefit can be achieved by advancing agronomic management based on the best farmers’ practices for vegetable production in a subtropical high-elevation mountain region.

China is among the largest emitters of carbon dioxide (CO2), worldwide Thus, its emissions mitigation is of global concern. The power generation sector is responsible for nearly half of China's total CO2 emissions and plays a key role in emissions mitigation. This study is an integrated evaluation of abatement technologies, including both low-carbon power generation technologies and retrofitting options for coal power plants. We draw marginal abatement cost curves for these technologies using the conservation supply curve method. Using scenario analysis for the years 2015 to 2030, we discuss the potential performance of abatement technologies. Marginal costs for the analyzed abatement technologies range from RMB − 357.41/ton CO2 to RMB 927.95/ton CO2. Furthermore, their cumulative mitigation potential relative to the baseline scenario could reach 35 billion tons of CO2 in 2015–2030, with low-carbon power generation technologies and coal power abatement technologies contributing 55% and 45% of the total mitigation, respectively. Our case study of China demonstrates the power generation sector's great potential to mitigate global emissions, and we suggest nuclear power, hydropower, and the comprehensive retrofitting of coal power as key technology options for the low-carbon transition of the energy system and long-term emissions mitigation strategies. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions from New Zealand's transport sector have experienced rapid growth since 1990. In this paper, we investigate the scope for a targeted price signal to curb emissions growth and help deliver on the country's Paris Agreement pledges. Cost burdens on various income groups are investigated, and experts' opinions are elicited to evaluate two types of carbon price policies (i.e. a carbon tax and an increase in the current ETS price). We use two methodological approaches in this paper. Estimates of the social cost of carbon and the price elasticity of fuel demand are used to understand the mitigation potential of a higher carbon price, while a multi-criteria analysis technique is used to understand experts' preferences between an ETS and a carbon tax. The findings are that with a price elasticity of transport fuel demand of around −0.7, a carbon price between NZD 100 (USD 65) per tonne of carbon dioxide (tCO2) and NZD 235 (USD 153)/tCO2 could reduce transport emissions by between 33% and 44% in 2030, respectively, from the 2016 level. The (uncompensated) cost-burdens on lower income households due to a hypothetical price of NZD 100/tCO2 and NZD 235/tCO2 are estimated to be around NZD 531 (USD 345)/year and NZD 670 (USD 436)/year per household respectively. Experts marginally favoured a carbon tax over an ETS because the revenue collected through a carbon tax could be utilized in a more holistic way to offset the tax burden on lower income households and fund emissions reduction technologies and infrastructures. Key policy insights A carbon price of NZD 235 (USD 153)/tCO2 implying a fuel price of NZD 3/litre (USD 1.95/litre) could reduce transport emissions by 44% in 2030 from the 2016 level. A fuel price of NZD 3/litre is comparable to fuel prices in the early 1980s, when these were at a historic high. A carbon price of NZD 235 (USD 153) would increase the annual domestic transport expenditure of lower income households by NZD 670 (USD 436), a 42% increase. A carbon tax is marginally preferred by interviewed experts to an increase in prices under the current ETS. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Tea Science is the property of Journal of Tea Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

China's 'dual carbon' goals seek to achieve peak CO 2 emissions before 2030 and carbon neutrality before 2060. China is one of the world's largest emitters of agricultural greenhouse gases. Although existing studies have evaluated GHG mitigation potential in Chinese agriculture, few built models by incorporating socioeconomic conditions, technology diffusion, and carbon pricing policies. This study developed a bottom-up Agricultural Technology Optimisation Model (ATOM) for GHG mitigation, which selected optimal mitigation measure portfolios by minimising costs based on inventories of agricultural GHG and mitigation measures. It was employed to quantify long-term mitigation potential in Chinese agriculture under a range of socioeconomic and carbon pricing scenarios. GHG emissions in Chinese agriculture totalled 720.3 MtCO 2 e in 2017. Assuming an SSP2 scenario, the maximum technical mitigation potential of the evaluated measures in 2060 will be 554.1 MtCO 2 e, with 78.2% contributed by mitigation measures for crop production. 38.9% of this potential is possibly achievable with negative cost mitigation measures, and carbon pricing can help achieve greater emission reductions. Chinese agriculture theoretically possesses significant mitigation potential, but the implementation of mitigation measures may be hindered by multiple obstacles. The government should adopt counterstrategies to ensure that the agricultural sector remains on track to meet China's carbon neutrality goal. • A bottom-up model (ATOM) for agricultural GHG mitigation was developed. • GHG mitigation pathways in Chinese agriculture were simulated. • Chinese agriculture theoretically possesses considerable GHG mitigation potential. • There is spatial heterogeneity in mitigation potential within Chinese agriculture. [ABSTRACT FROM AUTHOR]

Indonesia offers a dramatic opportunity to contribute to tackling climate change by deploying natural climate solutions (NCS), increasing carbon sequestration and storage through the protection, improved management, and restoration of drylands, peatlands, and mangrove ecosystems. Here, we estimate Indonesia’s NCS mitigation opportunity for the first time using national datasets. We calculated the maximum NCS mitigation potential extent using datasets of annual national land cover, peat soil, and critical lands. We collated a national emissions factor database for each pathway, calculated from a meta-analysis, recent publications from our team, and available literature. The maximum NCS mitigation potential in 2030 is 1.3 ± 0.04 GtCO _2 e yr ^−1 , based on the historical baseline period from 2009–2019. This maximum NCS potential is double Indonesia’s nationally determined contribution (NDC) target from the forestry and other land use sector. Of this potential opportunity, 77% comes from wetland ecosystems. Peatlands have the largest NCS mitigation potential (960 ± 15.4 MtCO _2 e yr ^−1 or 71.5 MgCO _2 e ha ^−1 yr ^−1 ) among all other ecosystems. Mangroves provide a smaller total potential (41.1 ± 1.4 MtCO _2 e yr ^−1 ) but have a much higher mitigation density (12.2 MgCO _2 e ha ^−1 yr ^−1 ) compared to dryland ecosystems (2.9 MgCO _2 e ha ^−1 yr ^−1 ). Therefore, protecting, managing, and restoring Indonesia’s wetlands is key to achieving the country’s emissions reduction target by 2030. The results of this study can be used to inform conservation programs and national climate policy to prioritize wetlands and other land sector initiatives to fulfill Indonesia’s NDC by 2030, while simultaneously providing additional co-benefits and contributing to COVID-19 recovery and economic sustainability.

China is facing a huge challenge in achieving its carbon neutrality goal by 2060 given that it is currently one of the world’s largest greenhouse gas (GHG) emitters and has set a very short timeline for going from peak emissions to carbon neutrality. Natural climate solutions (NCS) that protect, manage, and restore ecosystems have shown substantial potential for increasing carbon sinks or reducing GHG emissions to offset fossil fuel CO _2 emissions. This study quantified the mitigation potential of 18 NCS pathways in China at 0.67–1.65 Gigatonne of CO _2 equivalent (Gt CO _2 e) yr ^−1 averaged from 2020 to 2060, which is even larger than the size of the current national terrestrial carbon sink. Compared with a previous global estimate, our results show a lower mitigation potential in forest ecosystems but a much greater potential for cropland ecosystems in China. From 2020 to 2060, all 18 pathways combined can provide cost-effective mitigation compared to the global social cost of CO _2 emission and carbon prices, and 98.6% and 83.3% mitigation potential are cost-effective, respectively. This study further showed that immediate action provides the greatest mitigation. Our estimates highlight the important role of NCS in achieving the national carbon neutrality goal because of their large mitigation potential and cost-effectiveness.