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China is facing challenges to tackle the threat of climate change while reducing social inequality. Poverty eradication requires improvement in the living conditions of low-income households, which leads in turn to higher carbon footprints and may undermine the efforts of climate change mitigation. Previous studies have assessed the climate impacts of poverty eradication, but few have quantified how the additional carbon emissions of poverty eradication are shared at the subnational level in China and the impact on China's climate targets. We investigated the recent trend of carbon footprint inequality in China's provinces and estimated the climate burden of different poverty reduction schemes, measured by increased carbon emissions. The results indicate that poverty eradication will not impede the achievement of national climate targets, with an average annual household carbon footprint increase of 0.1%–1.2%. However, the carbon emissions growth in less developed provinces can be 4.0%, five times that in wealthy regions. Less developed regions suffer a greater climate burden because of poverty eradication, which may offset carbon reduction efforts. Therefore, interregional collaboration is needed to coordinate inequality reduction with investments in low-carbon trajectories in all provinces. [ABSTRACT FROM AUTHOR]

Ethylene is one of the most important products in the emissions-intensive petrochemical industry. Decarbonizing the ethylene industry is thus important for achieving global carbon neutrality. This study is the first to explore future long-term zero-emissions production pathways for the ethylene industry in China, the world's biggest ethylene producer. An optimization model was built in the context of China's carbon neutrality target of 2060. Four scenarios were developed where the policy ambitions for climate mitigation and for plastic management including waste were varied. Based on this, authors assessed the cumulative total emissions, technology options, future geographical location of ethylene production, and policy challenges associated with each scenario. This is also the first time that scope 3 emissions from waste incineration are included, motivated by the short lifetime of most ethylene products. Results show the cumulative CO 2 emissions for the scenarios differ considerably, ranging from 4.3 to 7.8 Gt, even if carbon neutrality by 2060 is achieved in all scenarios. The results suggest that ambitious plastic focused policies can result in lower costs and less cumulative emissions compared to ambitious climate focused policies. The results demonstrate the importance of adopting CCS for waste incineration. This reduces cumulative CO 2 emissions by up to 2 Gt. However, reduced overall demand and increased recycling rates should be priority options due to CCS challenges. Results suggest Chinese ethylene industry should adopt a mixed portfolio of production technologies, where the share of emission-intensive coal-based methanol-to-olefins is limited. These findings on decarbonization pathways can contribute to achieving the Paris agreement. [Display omitted] • Ambitious plastic policies lead to 1.3 Gt less cumulative CO 2 than climate policies. • Cumulative CO 2 until 2060 can be reduced by 3.5 Gt compared to reference scenario. • Adopting CCS in incineration can reduce cumulative CO 2 emissions by 2 Gt. • Ethylene industry should adopt a mixed production portfolio due to uncertainties. • Coal-based MTO with CCS does not appear to be a cost-competitive option. [ABSTRACT FROM AUTHOR]

• Implementation costs are a more relevant constraint to afforestation than opportunity costs. • Financial incentives for afforestation are constrained by market access and market prices. • Carbon-neutral and food multi-oriented land policies need further exploration. • Collaboration among global carbon markets can enhance CO 2 removal efficiency. Afforestation is a promising nature-based climate solution for mitigating climate change, but it is subject to a complex web of biophysical, cost-benefit, market, and policy processes. Although its biophysical feasibility has been established, the cost, market, and policy constraints that affect climate change mitigation through afforestation are still unclear. Here, we estimate such cost, market, and policy constraints on the basis of biophysical feasibility. Our findings reveal that implementation costs are a more relevant constraint than opportunity costs on mitigating climate change through afforestation. The China Certified Emission Reduction market currently provides only a 0.308 % incentive for climate change mitigation through afforestation, due to market access constraints. The current market prices of China Certified Emission Reduction, China Carbon Emissions Trading Exchange, and Nature Based Carbon Offset in Voluntary Carbon Market constrain 88.15 %, 87.95 %, and 85.75 % of CO 2 removal actions through afforestation, compared to the carbon price scenario (US$62.97 tCO 2 -1) of the EU Emissions Trading System. Moreover, land policy under the scenarios of prohibiting conversion of cultivated land to forest and forest restoration in degraded areas exhibit 8.87–29.59 % and 65.16–74.10 % constraints, respectively, on mitigating climate change through afforestation compared to land-use freedom conversion scenarios from 2020 to 2060. Thus, enhancing the incentive price of CO 2 removal, addressing the market access barrier, strengthening cooperation between global carbon markets, and exploring carbon–neutral and food multi-oriented land policies can be valuable sources of mitigation efforts over the next 40 years. [ABSTRACT FROM AUTHOR]

The ever-increasing challenges related to water security and climate mitigation underscore the pressing need for forward-thinking systems planning tools to drive urban sustainability transitions. In this study, we propose a novel city-level multi-objective planning framework that explores the nexus between carbon trading and water management, with the aim of facilitating water-efficient urban industrial restructuring. The framework integrates cap-and-trade mechanisms into a two-layered optimization model, creating an integrated approach to optimizing carbon emissions and generating economic opportunities for improving water efficiency. To illustrate the potential application of this framework, we conducted a case study focusing on Dongguan City, a water-stressed industrial metropolis in southern China. The results illustrate potential synergies between water planning strategies and carbon trading schemes, which could be harnessed to enable targeted reductions in water usage and carbon emissions. Furthermore, our findings identify the textile, apparel, and paper products manufacturing industries as primary candidates for strategic production scale reduction, emphasizing the importance of sustained support for the development of the computer and electronic manufacturing sector as a catalyst for urban sustainability transitions. By pioneering this new nexus-based perspective, our study offers valuable insights into long-term strategic planning for a low-carbon and resource-efficient urban economy. • Synergizing carbon trading and water management within a novel integrated planning framework. • Implementing resource-efficiency-driven optimization for water- and carbon-intensive manufacturing sectors. • Gaining insights into the specific roles of key manufacturing sectors in water management and carbon trading. • Introducing carbon trading systems may help in promoting water-efficient industrial restructuring. [Display omitted] [ABSTRACT FROM AUTHOR]

• Forest residues, a renewable energy, have great potential to substitute fossil fuels to reduce enormous pressures of energy shortages in mitigating climate change. However, it is a challenge to quantify forest residues at a fine spatial scale due to large spatial variations of forest species and lacking of suitable research methods. In addition, the natural decomposition of forest residue is often ignored in future greenhouse emission prediction, • We estimated the total forest residues in China reached 152.13 million t in 2018. The forest residues had faster decomposition rate (annual natural decomposition value of carbon from forest residues) in the first ten years, and then gradually decreased. In the first 14 years, the half forest residues was decomposed. The national contribution to climate change (CCC) from forest residues over one-hundred-year reached 49.27 million t CO 2 eq. The peak values of the provincial annual CCC were reached within 15 years and we found that the highest annual CCC occurred in the second year since the natural decomposition. • There are two major contents. First, a method is put forward to downscale the reserve of forest residue to county-level administrative unit. Prior to this, the resolution of the estimations was generally at provincial level. Obviously, more refined data was conducive to encourage the utilization of biomass by providing references for policymakers and investors. Second, a new index was implemented to assess the contribution of the natural decomposition of unused forest residues to climate change. • We estimated that CCC caused by their natural decomposition reaches 4.927 million t CO 2 eq, which was 0.96%−6.5% of other carbon emission sources (i.e. staple crops, inland water) in China. From a global perspective, such carbon emission was 0.015% of global wetland carbon emissions and 1.59% of global peat land carbon emissions. • Our study provides new data to support future climate mitigation, reducing the significant uncertainty in related research, and will make researchers, policymakers, and investors recognize the great potential of forest residues as an energy source and the significant contribution of their natural decomposition to climate change and promote carbon neutrality transition. Under the energy shortage and emerging climate change caused by fossil energy, forest residues were encouraged to be used as an energy resource. However, it is a challenge to quantify the forest residue at the fine spatial scale due to the available data and suitable research methods. We aimed to quantify the available forest residues in China at the county scale and clarify their potential contribution to climate change (CCC). The availability of forest residues reached 152.13 million t in 2018 in China. The CCC accumulated by natural decomposition of forest residues over one-hundred-year had reached 49.27 million tCO 2 eq. The peak values of provincial annual CCC were reached in the first 3 years in the southern region. The top four counties of CCC were all from Yunnan Province. The energy utilization of forest residues is of great significance to the management of forest resources. [Display omitted] [ABSTRACT FROM AUTHOR]

In an effort to contribute to climate change mitigation, China has committed to achieving its peak carbon by 2030 and carbon neutrality by 2060. However, reaching these goals will require a massive reduction in carbon emissions. The humans have to consume food to meet their survival needs. Furthermore, the society's demand for food is consistent with the development level of agricultural structures. At present, reducing environmental costs associated with food to adjust the agricultural structure has not received sufficient scientific attention. Because of this, the present study combines food consumption, climate change, and agricultural structure to design future scenarios based on the widely used SSP storyline. Moreover, in order for China to reach its carbon peak in 2030, this study applies a life-cycle approach to uncover the potential carbon reduction of Chinese residents under different dietary structures. From a demand perspective, this study puts forward recommendations for dietary restructuring and guides the direction of future agricultural restructuring in China. It also shows that a diet structure that replaces red meat with plant foods such as vegetables and fruits will have a more significant carbon reduction potential. The traditional agricultural structure consumes a large amount of food and produces a significant amount of greenhouse gases. Reducing meat and high-fat foods consumption may help reduce GHG emissions produced by food consumption. In addition, reducing the proportion of food used for feeding in the agricultural structure will also help achieve peak carbon targets. The shift in diet structure will advance China's agricultural structure and promote green agriculture development. • Food consumption and related carbon emissions within the 2030 scenario will continue to increase, with the highest share of rice consumption. • The carbon emissions of food consumption in the environmentally sustainable scenario will decrease. • Readjusting toward a more balanced diet could significantly contribute to the carbon peak goal. • A shift in dietary structure will promote agricultural restructuring. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) is a crucial technology for global climate mitigation. To implement large-scale CCUS, decisions about where and how to build a CO 2 transportation network are urgently required. However, previous studies are limited in proposing the economical transportation network for CCUS that considered comprehensive risks from socio-economic, geographical and geological factors. Here, we develop a pipeline layout planning model to investigate the cost-effective and reliable transportation network for CCUS. Results show that to meet the annual CO 2 emission reduction target of 654 million tons for CCUS in the coal-fired power sector under China's carbon neutral goal, pipelines with a total length of 17,589 km need to be constructed. The emission sources can be transported in pipelines with an average radius of 58 km, and with diameters of 8, 12, and 16 inches. Northeast, north, and northwest China are the main areas suitable for pipeline construction. • Northeast, North, and Northwest in China are vital areas for capture, transport, and storage. • Five large-scale pipeline network groups can be constructed in China. • Pipeline construction is greatly affected by a variety of practical factors. [ABSTRACT FROM AUTHOR]

• An interval-parameter bi-level programming (IBP) method is proposed. • IBP can tackle conflicts between two-level decision makers under uncertainty. • An IBP_CES model is developed for planning China's energy system in 2021–2050. • The annual CO 2 emission would reduce up to 11.0% by 2050 compared with 2020 level. • Results show that IBP_CES compromises mitigation goals and economic decisions. To reach the goal of carbon-neutral society, synergistic approaches based on mathematical models that are capable of planning energy system associated with complex uncertainty and hierarchical structure are desired. In this study, an interval-parameter bi-level programming (IBP) method that is effective for solving hierarchical decision-making problems with conflict objectives and uncertainty is developed. Then, an IBP based China's energy system model (abbreviated as IBP_CES) is formulated for mainland China during 2021–2050, where the higher-level objective of minimizing carbon dioxide (CO 2) emission is given priority, following by the lower-level objective of minimizing system cost. Results from IBP_CES show that, although China's energy supply would still rely heavily on fossil fuels, the share of coal would decrease to 33.9% by 2050. Results also disclose that the national CO 2 emission would reach the peak value during 2026-2030 and then decline rapidly due to development of renewable energy and promotion of carbon-treatment technology which is beneficial for government to achieve carbon neutrality goals. In addition, compared to the traditional single-level model, CO 2 emission from IBP_CES can decrease by 5.9%, demonstrating that IBP_CES is more superior in energy system decarbonization. The findings can help decision makers to well understand the interactions and tradeoffs between climate mitigation and economic development, and provide effective information on clean, sustainable and deep-decarbonized development strategies. [ABSTRACT FROM AUTHOR]

• We construct a multi-model comparison framework by employing typical IAMs. • We examine how China will contribute to the global 1.5 °C climate target. • China could contribute nearly one-fifth of the global negative emissions by 2100. • The proportion of BECCS could dramatically increase to 29% under the 1.5 °C case. • Energy demand control may rely more on coordination between CCS and clean energy. Enhancing the warm-limiting targets to from below 2 °C to 1.5 °C is of great significance for climate change mitigation, during which the carbon capture and storage (CCS) of China is playing an important role. By framing a multi-model analysis to compare IAMs, this study aims to explore how China can contribute to the global 1.5 °C target, consistent with achieving its carbon neutrality goal. Our multi-model assessment shows that the enhanced targets will advance the reach time of China's carbon peak and neutrality. Under a relatively smooth emission path curve with CCS, China's carbon emissions will decrease sharply by the end of this century. It is estimated that China's negative carbon emissions will contribute nearly one-fifth of the global negative emissions in 2100, with its CCS-captured emissions accounting for 14%. In the energy system, fossil- and biomass-CCS will develop rapidly, with the proportion of biomass with CCS dramatically increasing to 29% and 17% under the 1.5 °C and 2 °C scenarios, respectively. There will be a relatively large gap between the capital and final use costs of CCS, which may weaken the technical advantage when competing with renewables during the life cycle. While the overall control of the energy consumption in the later period will rely more on the proportional adjustment and the coordination between biomass with CCS and clean energy. [ABSTRACT FROM AUTHOR]

[Display omitted] • TUEEC in 10 urban agglomerations in China are substantially different. • TUEEC within urban agglomeration have an impact on CO 2 emissions. • Ecological construction partially mitigated emissions growth. • Guarding against unsustainable development is vital to carbon neutral. Urban agglomerations are major generators of CO 2 emissions owing to human socioeconomic activities. Evaluating the trade-offs between urban expansion and ecological construction during rapid urbanization is a crucial step towards climate change mitigation and carbon neutrality. This study investigated the impacts of trade-offs between urban expansion and ecological construction on CO 2 emissions using multi-source data and spatial and statistical analysis. Ten urban agglomerations in China, with various development levels, were selected as study areas. The results indicated that (1) urban development in the 10 urban agglomerations expanded by 90%–288.9%, while ecological land changed by −28.1–2.3%. (2) CO 2 emissions grew by 154.2–291.2% in urban agglomerations, and the south and east of China emitted more CO 2. The high-value clusters of CO 2 inside of all urban agglomerations expanded outward from cities. (3) Urban expansion increased emissions, while ecological construction partially mitigated emissions growth. Moreover, ecological development within cities helps to reduce excessive urban emissions and should be given more attention. (4) It is as important to guard against unsustainable development as it is to reduce existing high emissions. Low-carbon development paths must continue to be supported in western China. On the basis of the results, we identify important implications for meeting China's target of carbon neutrality. These contribute to an understanding of future development modes for urban agglomerations and reveal the impact of trade-offs of land use on CO 2 emissions. [ABSTRACT FROM AUTHOR]

Building sector plays a significant role in China's ambitous climate targets to peak carbon emissions (CEs) by 2030 and to realize carbon neutral by 2060. However, studies in characterizing the CEs of urban residential buildings from life-cycle perspective at regional level are still limited, especially for the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in China. Here, life cycle assessment method and improved building stock turnover model were employed to quantify the annual CEs of urban residential buildings (including materialization CEs of the newly-built urban residential buildings, operational CEs of the existing urban residential buildings, and CEs generated from the demolition of the existing urban residential buildings) in GBA cities from 2000 to 2018. The results show that the total CEs increased dramatically from 44.5 Mt. CO 2 e in 2000 to 75.1 Mt. CO 2 e in 2018 with an annual growth rate by approximately 3%. The CEs from operation stage accounted for around 70%, and recycling building wastes could reduce 7.5% emissions. Compared with other bay areas globally, the operational CEs of urban residential building in GBA became the highest since 2014. Therefore, climate actions in energy saving and emission mitigation are required. Based on scenario analysis, we estimated that Huizhou city can reach the peak target by 2020 if taking some effective measures. These emission findings could provide data references and suggestions for the low-carbon development path for urban residential buildings in GBA and other global cities. [Display omitted] • This study evaluates the life-cycle carbon emissions of urban residential buildings in bay area. • This study provides a reference for the carbon emission of building unit floor area. • Operation stage is the focus of emission reduction in urban residential buildings. • This study explores the path of peak carbon emissions from residential buildings. [ABSTRACT FROM AUTHOR]

China has demonstrated great commitment to take more vigorous and effective approaches to peak carbon emissions by 2030 and achieve carbon neutrality by 2060. China's actions to mitigate CO 2 emissions are expected to simultaneously reduce co-emitted air pollutants and reduce premature deaths. This study investigates the future changes in international and regional ozone and associated health and economic benefits of stringent climate mitigation policy in China by 2050. Results show that China's stringent mitigation policy positively impacts air quality and public health in China and its downwind transboundary regions, Japan and South Korea. More specifically, approximately 15,800 and 35,550 ozone-related premature deaths will be avoided globally in 2030 and 2050 worldwide, with 78% and 76% happening in China. The avoided ozone-related mortality could save 3 billion USD in 2030 and 10 billion USD in 2050 based on the willingness to pay method. Figure 2 Avoided ozone-related morality under China's strict climate mitigation policy in different regions in 2030 and 2050 [Display omitted] [ABSTRACT FROM AUTHOR]

Achieving the carbon neutral targets before year 2060 is one of the important commitments for mitigating global climate change by Chinese government. However, the manner in which one would maximize the carbon sequestration of the planted forests is still unclear. Estimating accurately the carbon balance in forestry depends highly on the dynamics of numerous delay-released carbon pools (e.g., harvest residues, wood products), thus the strategies used to account for the carbon emissions of these components may have great influences on the decision-making and profitability associated with planted forests. This study developed a tool that allows forest managers and policy makers to analyze the effects of alternative accounting strategies for recognizing carbon emissions on the optimal rotation lengths and profitability of planted forests. The considered carbon balance not only refers to the within-forest pools, e.g., living biomass, harvest residues, annually generated litters and dead trees, but also refers to the outside-forest pools that include wood products, biofuel, operating process and substitution effect. The obtained results indicated that the lengths of optimal forest rotation decreased significantly with increases in site index, planting density and discount rate, while they increased dramatically with increases of carbon price. The gaps in rotation lengths were as large as 13.5 years, 6.9 years, 27.6 years and 11.0 years, respectively for the ranges of site index (10–18 m), planting density (2500–4444 trees per hectare), discount rate (1%–5%), and carbon prices (0–880 CNY/ton CO 2) assumed. The effects of delay-released carbon pools on the optimal rotation lengths were not significant, when the substitution effects of wood products and biofuels were considered under the current carbon trading markets; however, some exceptions were observed when a very high carbon price (880 CNY/ton CO 2) was assumed. [Display omitted] • A management tool that considers carbon balance and wood production was developed. • The optimal rotations are sensitive to forest- and economic-based variables. • The delayed effects of carbon emissions on optimal rotations were offset by substitution effects. • Pricing CO 2 sequestrated in forests can increase optimal rotations and profitability. [ABSTRACT FROM AUTHOR]