Chinese cities exhibit varying degrees of decoupling of economic growth and CO2 emissions between 2005 and 2015

Integrating climate resilience with sports, exercise, and public health expenditures on sustainable environment: Evidence from coastal regions of China

The adoption of environmentally-friendly habits has become more crucial in the present period as a means to mitigate the rate of environmental degradation and its detrimental consequences. The augmentation of sports, exercise and physical activities has been associated with favourable health outcomes, in addition to the ability to mitigate carbon emissions resulting from vehicular transportation. Consequently, the objective of this study is to examine the influence of sports, exercise, and physical activities, along with public health expenditure, on the environmental performance of China's coastal regions throughout the period spanning from 2010 to 2019. The proposed study employs the Feasible Generalized Least Squares (F.G.L.S) and the Generalized Method of Moments (G.M.M) methodologies. Results show that participation in sports and other forms of physical activity significantly improves environmental performance in China's coastal areas. Likewise, a robust negative correlation exists between air pollution and healthcare expenses, hence favouring enhanced environmental outcomes. Nevertheless, it is important to acknowledge that economic expansion has a direct correlation with increased emissions, hence harming environmental performance. There exists compelling evidence indicating a significant impact on environmental quality resulting from the combined influence of heightened health expenditures and increased engagement in sports. This is demonstrated by the presence of an interaction term between health expenses and sports activities. The findings of this study suggest that there is a requirement to re-evaluate healthcare spending initiatives and sporting activities in order to effectively pursue carbon neutrality goals and improve environmental sustainability.

City-level livestock methane emissions in China from 2010 to 2020

Livestock constitute the world's largest anthropogenic source of methane (CH4), providing high-protein food to humans but also causing notable climate risks. With rapid urbanization and increasing income levels in China, the livestock sector will face even higher emission pressures, which could jeopardize China's carbon neutrality target. To formulate targeted methane reduction measures, it is crucial to estimate historical and current emissions on fine geographical scales, considering the high spatial heterogeneity and temporal variability of livestock emissions. However, there is currently a lack of time-series data on city-level livestock methane emissions in China, despite the flourishing livestock industry and large amount of meat consumed. In this study, we constructed a city-level livestock methane emission inventory with dynamic spatial-temporal emission factors considering biological, management, and environmental factors from 2010 to 2020 in China. This inventory could serve as a basic database for related research and future methane mitigation policy formulation, given the population boom and dietary changes.

Effects of trade liberalization on the global decoupling and decomposition of CO2 emissions from economic growth

Evidence of climate change is widespread and severe across all parts of the world. This poses a threat to humanity, and the entire environment. Appropriate policies are therefore required to help reduce greenhouse gas emission levels, limit the rate of global warming and its impact on climate change while pursuing national growth targets. This study employs the Tapio decoupling method to analyse the decoupling relationship (DR) between economic growth and carbon dioxide (CO2) emissions from 1998 to 2018. We also apply the Logarithmic Mean Divisia Index (LMDI) decomposition method on an extended Kaya identity to analyse CO2 emissions drivers in 145 countries. Last, the study examined the relative impacts of trade intensity and trade efficiency on the DR between economic growth and CO2 emissions. The results revealed that regions with relatively many developing and emerging countries (i.e., SSA, EAP, LAC, MENA, and SA) generally performed Weak Decoupling (WD), Expansive Negative Decoupling (END) and Expansive Coupling (EC), and the decoupling process was largely unstable. The ECA and NA regions on the other hand, which are typically composed of developed economies performed stable WD and Strong Decoupling (SD) statuses throughout the study period. The evidence further revealed that while trade intensity, activity, population, output per carbon emission and Carbon Intensity (CI) effects promote CO2 emissions, trade efficiency and energy intensity (EI) hinder emissions. We recommend that developing countries should enforce laws and cooperate with the developed economies to gain access to green technology to promote environmental sustainability.

Heavy industrial aggregation area's green transformation optimisation pathways exploration with synergistic reduction pursue of CO2 and gaseous pollutants

A profound green transformation of China's heavy industrial aggregation regions is required to conquer severe air pollution, and fulfill carbon peak pledge. Here, to clarify the coordinated mechanism and an optimal roadmap for the reduction of CO2 and gaseous pollutants, we integrated input-output modelling, system dynamics, and multi-objective programming to construct a CO2 and gaseous pollutants synergistic reduction model initially; investigated incentive approaches from 2020 to 2035; Hebei, with the largest steel production in China, was adopted as a demonstrative region. Results revealed that intensive dual control of efficiency and structure in energy and industry can accelerate achieving carbon peak in 2029. In optimal case, CO2 emission intensity can reach a 75.2% reduction compared to 2020, and gaseous pollutants continue decline simultaneously (SO2 and NOx can drop by 63% and 48%); and the synergistic reduction level is expected to improve. Thus, vigorously develop decoupling between economy-air pollution-carbon reduction in Hebei. As opposed to efficiency improvement, structural adjustments were demonstrated to be more effective than short-term efficiency improvements. In addition, the estimated development potential of traditional heavy industries such as steel and petrochemicals is limited, whereas the equipment manufacturing industry, closely linked to traditional industries, is expected to continue its development. Furthermore, although in the electrification process, coal consumption is still needed because of its indispensable role in the production process of heavy industries. The results can facilitate policy-making for heavy industrial aggregation areas' green transformation in shaping policies and actions with clear objectives, effective measures, and sound coordination.

Revealing varying relationships between wastewater mercury emissions and economic growth in Chinese cities

Mercury emission from industrial wastewater has a great impact on the aquatic environment but is not well studied. Inventory analysis, decoupling and decomposition methods have been conducted based on the China Pollution Source Census dataset, which combines industry removal efficiencies to calculate mercury emissions from industrial wastewater in 340 cities in China during 2000-2010. The results show that over these 11 years, total mercury emissions and per capita mercury emissions increased by approximately 5 times, while the emission intensity increased by only about 3%. From 2000 to 2010, only 0.59% of cities showed strong decoupling between economic growth and mercury emissions, and 37.65% of cities showed weak decoupling, whereas 38.82% of cities showed negative decoupling. We attribute the decoupling of economic development and emissions in individual cities to several socioeconomic factors and find that a decline in emission intensity is the main driver. The Gini coefficient indicates a significant imbalance between cities' emissions, but this situation improved during 2000-2010. The objective of this article is to provide a historical perspective on the situation of mercury emissions from wastewater in China, thereby contributing' to the broader understanding of industrial pollution.

A dataset of low-carbon energy transition index for Chinese cities 2003-2019

Cities are at the heart of climate change mitigation as they account for over 70% of global carbon emissions. However, cities vary in their energy systems and socioeconomic capacities to transition to renewable energy. To address this heterogeneity, this study proposes an Energy Transition Index (ETI) specifically designed for cities, and applies it to track the progress of energy transition in Chinese cities. The city-level ETI framework is based on the national ETI developed by the World Economic Forum (WEF) and comprises two sub-indexes: the Energy System Performance sub-index, which evaluates the current status of cities' energy systems in terms of energy transition, and the Transition Readiness sub-index, which assesses their socioeconomic capacity for future energy transition. The initial version of the dataset includes ETI and its sub-indexes for 282 Chinese cities from 2003 to 2019, with annual updates planned. The spatiotemporal data provided by the dataset facilitates research into the energy transition roadmap for different cities, which can help China achieve its energy transition goals.

Similar cities, but diverse carbon controls: Inspiration from the Yangtze River Delta megacity cluster in China

Addressing global uneven urban development and the urgent need to reduce carbon emissions (CE), this study presents a new method for calculating urban socioeconomic development indexes using a variety of data sources. Using the Yangtze River Delta as an example, we categorize urban areas into core, transitional, and peripheral cities. With the help of extended Kaya-index decomposition models, we evaluate the effects of regional industrial growth, consumer markets, and spatial expansion on urban CE. The research explores differences in CE drivers across and within these city categories. Our findings reveal that in core cities, 31.5 % of CE is due to the industrial structure and 14.9 % due to population density. In transitional cities, CE increases by 60.22 % primarily due to industrial structure and consumer consumption. Peripheral cities, on the other hand, have a complex set of causes for CE, with per capita living, spatial expansion, population size, urbanization, and consumption limitation contributing to 91.97 %, 10.73 %, 14.2 %, 9.34 %, and 24.92 % of CE respectively. Varied factors influence CE intensity differences within each city group. Cleaner production technologies and potential carbon reductions in consumption and industry are identified as key strategies for compensating CE reduction. We propose the adoption of carbon function zoning in urban clusters to leverage the role of carbon function in each area. Territorial spatial planning should ensure a balanced layout of production, living, and ecological functions. Residents' consumption, being the key factor driving CE, must transition toward green, low-carbon consumption, reinforced by societal norms and responsibilities. This research provides valuable theoretical and practical insights into urban classification and CE reduction strategies.

Multiperspective Decoupling Analyses between Global Embodied Carbon Chains and Global Value Chains

Decoupling global economic growth from carbon emissions is essential for mitigating global climate change while maintaining continuous economic growth. Traditional production-side decoupling analysis alone is insufficient to capture the decoupling status between carbon emissions and the value added throughout global supply chains. This study investigates the decoupling status between value added and greenhouse gas (GHG) emissions during 1995-2019 from consumption and income perspectives. We find that the decoupling statuses of 17 regions (especially Russia, Australia, and Malta) show significant differences across multiple perspectives. For example, Malta's direct GHG emissions decreased with its GDP growth from a production perspective (i.e., achieved strong decoupling). However, its consumption-based GHG emissions increased with the growth of consumption-based value added (i.e., expansive negative decoupling). Moreover, most international pairs have not yet achieved strong decoupling from consumption and income perspectives. International multilateral cooperation is crucial for decoupling global GHG emissions from economic growth across global supply chains. This study provides insights into the decoupling between embodied GHG emissions and value added from consumption and income perspectives. The findings of this study can complement existing policies on global GHG emission mitigation and sustainable development.

Leveraging opportunity of low carbon transition by super-emitter cities in China

Chinese cities are core in the national carbon mitigation and largely affect global decarbonisation initiatives, yet disparities between cities challenge country-wide progress. Low-carbon transition should preferably lead to a convergence of both equity and mitigation targets among cities. Inter-city supply chains that link the production and consumption of cities are a factor in shaping inequality and mitigation but less considered aggregately. Here, we modelled supply chains of 309 Chinese cities for 2012 to quantify carbon footprint inequality, as well as explored a leverage opportunity to achieve an inclusive low-carbon transition. We revealed significant carbon inequalities: the 10 richest cities in China have per capita carbon footprints comparable to the US level, while half of the Chinese cities sit below the global average. Inter-city supply chains in China, which are associated with 80% of carbon emissions, imply substantial carbon leakage risks and also contribute to socioeconomic disparities. However, the significant carbon inequality implies a leveraging opportunity that substantial mitigation can be achieved by 32 super-emitting cities. If the super-emitting cities adopt their differentiated mitigation pathway based on affluence, industrial structure, and role of supply chains, up to 1.4 Gt carbon quota can be created, raising 30% of the projected carbon quota to carbon peak. The additional carbon quota allows the average living standard of the other 60% of Chinese people to reach an upper-middle-income level, highlighting collaborative mechanism at the city level has a great potential to lead to a convergence of both equity and mitigation targets.

Emission accounting and drivers in Central Asian countries

Emerging countries are at the frontier of climate change actions, and carbon emissions accounting provides a quantifiable measure of the environmental impact of economic activities, which allows for comparisons of emissions across different entities. However, currently there is no study covering detailed emissions inventories for emerging countries in Central Asian. This paper compiles detailed and accurate carbon emissions inventories in several Central Asian countries (i.e., Kazakhstan, Kyrgyzstan, Pakistan, Palestine, Tajikistan, and Uzbekistan) during the period 2010-2020. Using the IPCC administrative territorial approach, we for the first time compile their emissions inventories in 47 economic sectors and five energy categories. Moreover, we also investigate decoupling status based on Tapio decoupling model and examine emissions driving factors based on the index decomposition analysis method. The primary results illustrate that carbon emissions in Central Asian countries are increasing with huge differences. Decoupling results highlight that most of the sample countries still need more effort to decouple the economy and emissions except that Pakistan achieves an ideal strong decoupling state. The results of the decomposition indicate that the economy and population both raise emissions, while energy intensity and carbon intensity are negative drivers in some countries. We propose practical policy implications for decarbonization and energy transition roadmap in Central Asian countries.

Agricultural Methane Emissions in China: Inventories, Driving Forces and Mitigation Strategies

Identification of the spatial distribution, driving forces, and future trends of agricultural methane (AGM) emissions is necessary to develop differentiated emission control pathways and achieve carbon neutrality by 2060 in China, which is the largest emitter of AGM. However, such research is currently lacking. Here, we estimated China's AGM emissions from 2010 to 2020 and then decomposed six factors that affect AGM emissions via the LMDI model. The results indicated that the AGM emissions in China in 2020 were 23.39 Tg, with enteric fermentation being the largest source, accounting for 43.9% of the total emissions. A total of 39.3% of the AGM emissions were from western China. The main driver of AGM emission reduction was emission intensity, accounting for 59% and 33.7% of methane emission reduction in the livestock sector and rice cultivation, respectively. Additionally, higher levels of urbanization contributed to AGM emission reductions, accounting for 31.3% and 43.0% of the livestock sector and rice cultivation emission reductions, respectively. Based on the SSP-RCP scenarios, we found that China's AGM emissions in 2060 were reduced by approximately 90% through a combination of technology measures, behavioral changes, and innovation policies. Our study provides a scientific basis for optimizing existing AGM emission reduction policies not only in China but also potentially in other high AGM-emitting countries, such as India and Brazil.

The heterogeneous driving forces behind carbon emissions change in 30 selective emerging economies

Emerging economies are predicted to be future emission hotspots due to expected levels of urbanization and industrialization, and their CO₂ emissions are receiving more scrutiny. However, the driving forces underlying dynamic change in emissions are poorly understood, despite their crucial role in developing targeted mitigating pathways. We firstly compile energy-related emissions of 30 selective emerging economies from 2010 to 2018. Then, three growth patterns of emissions in these economies have been identified through emission data, which imply different low-carbon pathways. Most emerging economies saw an increase of varying degrees in emissions, driven by economic growth and partly offset by better energy efficiency and improvements in energy mixes. Furthermore, the industrial structure was another factor that slowed emissions, especially in Latin America and the Caribbean. Our research contributes to the heterogeneous exploration of CO₂ emissions produced by energy among sectors and the creation of low-carbon development pathways in emerging economies.

From pilots to demonstrations: the green economic development effect of low-carbon city pilot policies

Accurately assessing the impact of low-carbon urban construction on green economic development has great significance for achieving economic development with environmental protection, and for building an ecological civilization and a beautiful China. Based on panel data for 271 cities in China from 2004 to 2019, multi-period and spatial difference-in-difference econometric models were used to comprehensively investigate the impact of three batches of low-carbon city pilot policies on green economic development, finding the following: The contribution of low-carbon urban construction on urban green economic development is significant and positive, and still holds under a series of robustness tests. Parallel trend tests also show a lag in the policy effect, and the effect is strengthened over policy implementation time. Green orientation of technological progress, green transformation of industry, and green upgrade of consumption are important channels for the effect of the policies. The promotion effect of low-carbon city construction is stronger in the central and northern cities, and in cities with high green economic development, than in western and southern cities, and those with low green economic development. Construction of low-carbon pilot cities not only promotes their own green economic development, but also that in neighboring cities, exerting a demonstration effect. This effect is greater in urban areas. This study provides empirical support for policy planning to promote low-carbon urban construction across the country.

Exploring spatiotemporal pattern and agglomeration of road CO2 emissions in Guangdong, China

Road transport is a prominent source of carbon emissions. However, fine-grained regional estimations on road carbon dioxide (CO2) emissions are still lacking. This study estimates road CO2 emissions in Guangdong Province, China, at high spatiotemporal resolution, with a bottom-up framework leveraging massive vehicle trajectory data. We unveil the spatiotemporal pattern of regional road CO2 emissions and highlight the contrasts among cities. The Greater Bay Area (GBA) is found to produce 76 % of the total emissions, wherein Guangzhou emits the most while Shenzhen has the highest emission intensity. Emission agglomeration is still an under-explored field, which we advance in this paper. We propose Quantile-based Hierarchical DBSCAN (QH-DBSCAN) to explore road CO2 emission agglomeration in GBA. Our method is the first one to identify the specific location and scope of emission hotspots. Emission hotspots exhibit significant concentration on major urban centers. Considering emission characteristics from multiple perspectives, we derive six emission categories, including four emission zones and two emission connectors. The density-based property of our method results in spatially contiguous regions with similar emission patterns. Accordingly, we divide policy zones and propose targeted strategies for road carbon reduction. The study provides new technologies and insights to achieve regional sustainable development.

Unstable decoupling of CO2 emissions from sectoral economic growth calls for decarbonization policies based on multi-perspective accounting: a case study of Zhejiang, China

Decoupling CO₂ emissions from economic growth is an important cornerstone of a country's decarbonization policy. Existing research in this avenue has mainly focused on decoupling the production-based (PB) CO₂ emissions from economic growth at the national level, while decoupling the consumption-based (CB) and income-based (IB) CO₂ emissions from economic growth, especially at the sectoral level, has received less attention. Using China's Zhejiang province as a case study, we conduct one of the first studies focused on decoupling the PB, CB, and IB CO₂ emissions from economic growth at the sectoral level. Our results reveal that (1) during 2002-2017, the sectoral decoupling level varies greatly among the three different perspectives; (2) most of the examined sectors were in unstable decoupling states while some sectors even reverted to coupling states; and (3) the drivers of CO₂ emissions at the sectoral level reveal important factors, such as emissions intensity, production structure, and final demand structure, that contribute toward decarbonization. Our study demonstrates to policymakers how utilizing a multi-perspective evaluation of the decoupling of emissions from sectoral economic growth can improve the accuracy of decarbonization policies and identify critical sectors toward CO₂ reduction objectives.

Evaluating the symmetric and asymmetric effects of fossil fuel energy consumption and international capital flows on environmental sustainability: a case of South Asia

South Asia is primarily affected by environmental degradation. As a result, it is worthwhile to explore the impact of international capital flows on the ecological sustainability of the South Asian region. There are many studies in the literature on the CO₂-remittances nexus, CO₂-FDI nexus, and CO₂-economic growth; however, no study has yet taken remittances and FDI into account in the symmetric and asymmetric model for the South Asian region. To address the research gap, this study investigates the effect of international capital flows, fossil fuel energy consumption, and economic growth on South Asian carbon emissions. This study examines the effect of fossil fuel energy consumption, remittances, foreign direct investment, and economic growth on the environmental sustainability of the South Asian region from 1975 to 2020. Autoregressive distributive lag (ARDL) and non-linear ARDL (NARDL) models are used to estimate the symmetrical and asymmetrical relationships among the variables. The findings of the ARDL models reveal that fossil fuel energy consumption and economic growth increase while remittances and FDI decrease carbon dioxide (CO₂) in the long run. According to the NARDL empirical findings, positive remittances and negative FDI shock reduce CO₂. Besides, the positive and negative fossil fuel energy consumption shock increases CO₂. Moreover, the positive (negative) economic growth shock increases (decreases) CO₂. The cumulative dynamic multipliers revealed the adjustment pattern to new long-run equilibria. The study recommends that policymakers regard remittances and FDI as policy instruments, particularly when developing long-term strategies and policies connected to environmental quality.

Urban land use carbon emission intensity in China under the "double carbon" targets: spatiotemporal patterns and evolution trend

In-depth research on the spatiotemporal patterns and evolution trend of urban land use carbon emission intensity (ULUCEI) can reveal the internal relationship between urban land use and carbon emissions, which is crucial for achieving carbon emission reduction and "double carbon" targets. This paper proposed a conceptual framework of ULUCEI; the methods of kernel density estimation (KDE), exploratory spatial data analysis (ESDA), and spatial Markov chains were adopted for exploring the spatiotemporal patterns and evolution trend of China's ULUCEI from 2000 to 2017. The following conclusions are drawn through research. (1) There was an increasing trend in ULUCEI in China from 0.102 in 2000 to 0.283 in 2017. From the regional perspective, the ULUCEI in the eastern region is markedly higher than that in the central and western regions. Moreover, the results of nuclear density estimation indicate that China's ULUCEI shows an obvious upward and polarized trend. (2) China's ULUCEI shows a positive spatial autocorrelation. The types of spatial agglomeration include "high-high" agglomeration, "high-low" polarization, "low-high" collapse, and "low-low" homogeneity, and there are obvious disparities in the distribution rules of cities with different spatial agglomeration forms. (3) China's ULUCEI presents strong stability and "club convergence" trend. Moreover, spatial factors significantly affect the dynamic transition of China's ULUCEI, and its effect on the shifting upwards gradually enhances with increasing lag type. This paper therefore suggests that policymakers should formulate differentiated urban land low-carbon use models and carbon emission reduction policies to reduce ULUCEI.

The evaluation of greenhouse gas emissions from sewage treatment with urbanization: Understanding the opportunities and challenges for climate change mitigation in China's low-carbon pilot city, Shenzhen

Sewage treatment provides a pathway for anthropogenic water purification that can address the growth in domestic sewage volumes due to urbanization and protect the aquatic environment. However, the process can also generate greenhouse gases (GHGs), which are sometimes termed "unrestricted" GHG emissions and are neglected by low carbon policies. A combination of a life cycle analysis (LCA), data envelopment analysis (DEA), and questionnaire survey was used to evaluate sewage treatment related GHG emissions and assess the GHG emission reduction efficiencies during 2005-2020, as well as determine the opinions of environmental managers regarding the threats to climate change mitigation posed by sewage treatment in the low carbon pilot city of Shenzhen, China. There were four main results. (1) GHG emissions from sewage treatment plants (STPs) in Shenzhen increased gradually from 0.22 Mt. CO₂-eq in 2005 to 1.16 Mt. CO₂-eq in 2020 with an emission intensity ranging from 0.41 to 0.58 kg CO₂-eq/m³, mainly due to the indirect emissions from sludge disposal (35-57 %). Longgang administrative district was the hotspot of these GHG emissions during the study period. (2) Reductions in GHG emissions were achieved in most years since 2012 with the greatest efficiency observed in 2020. (3) Beyond the environmental managers' perceptions of the challenges in GHG mitigation, future sewage treatment may create the potential for more substantial GHG emission growth compared to the emissions from energy combustion, due to policy deficiencies, growth in sewage volumes, and the enforcement of stricter effluent quality control. (4) Several opportunities to overcome these barriers were considered including innovational environmental management, planting of constructed wetlands, and the promotion of water-saving behavior. This case study of Shenzhen has valuable implications for the synergistic governance of water pollution and climate change mitigation in megacities in China and elsewhere, enabling a move towards a future carbon-neutral society.

Measuring the low-carbon energy transition in Chinese cities

Cities' transition from fossil-based systems of energy production and consumption to renewable energy sources-the energy transition-is critical to mitigating climate change impact as cities' energy consumption and CO₂ emissions account for two-thirds and over 70% of the world's total, respectively. Given cities' heterogeneity, they need specific low-carbon roadmaps instead of one-size-fits-all approaches. Here, we used an Energy Transition Index (ETI) to characterize the city-level energy transitions from energy system performance and transition readiness dimensions. The ETI scores for 282 cities in China revealed a significant heterogeneity across cities and over time, and the gap between the cities in the top and bottom quartiles was persistent. We estimated that China's energy and carbon intensity could decrease by 34% and 32%, respectively, and that carbon per capita could fall by 17% if each city modestly follows the sustainable development path forged by the best performing cities with similar economic structures.

Characterizing Carbon Emissions and the Associations with Socio-Economic Development in Chinese Cities

Reducing carbon emissions in cities is crucial for addressing climate change, while the city-level emissions of different compositions and their relationships with socio-economic features remain largely unknown in China. Here, we explored the city-level emission pattern from the industrial, transportation, and household sectors and the emission intensity, as well as their associations with socio-economic features in China, using the up-to-date (2020) CO₂ emissions based on 0.1° grid (10 × 10 km) emission data. The results show that: (1) CO₂ emissions from the industrial sector were considerably dominant (78%), followed by indirect (10%), transportation (8%), and household (2%) emissions on the national scale; (2) combining total emissions with emission intensity, high emission-high intensity cities, which are the most noteworthy regions, were concentrated in the North, while low emission-low intensity types mainly occurred in the South-West; (3) cities with a higher GDP tend to emit more CO₂, while higher-income cities tend to emit less CO₂, especially from the household sector. Cities with a developed economy, as indicated by GDP and income, would have low emissions per GDP, representing a high emission efficiency. Reducing the proportion of the secondary sector of the economy could significantly decrease CO₂ emissions, especially for industrial cities. Therefore, the carbon reduction policy in China should focus on the industrial cities in the North with high emission-high intensity performance. Increasing the income and proportion of the tertiary industry and encouraging compact cities can effectively reduce the total emissions during the economic development and urbanization process.

City-level emission peak and drivers in China

China is playing an increasing role in global climate change mitigation, and local authorities need more city-specific information on the emissions trends and patterns when designing low-carbon policies. This study provides the most comprehensive CO₂ emission inventories of 287 Chinese cities from 2001 to 2019. The emission inventories are compiled for 47 economic sectors and include energy-related emissions for 17 types of fossil fuels and process-related emissions from cement production. We further investigate the state of the emission peak in each city and reveal hidden driving forces. The results show that 38 cities have proactively peaked their emissions for at least five years and another 21 cities also have emission decline, but passively. The 38 proactively peaked cities achieved emission decline mainly by efficiency improvements and structural changes in energy use, while the 21 passively emission declined cities reduced emissions at the cost of economic recession or population loss. We propose that those passively emission declined cities need to face up to the reasons that caused the emission to decline, and fully exploit the opportunities provided by industrial innovation and green investment brought by low-carbon targets to achieve economic recovery and carbon mitigation goals. Proactively peaked cities need to seek strategies to maintain the downward trend in emissions and avoid an emission rebound and thus provide successful models for cities with still growing emissions to achieve an emission peak.

Impact from the evolution of private vehicle fleet composition on traffic related emissions in the small-medium automotive city

Understanding the emission characteristics in the evolution of private vehicle fleet composition has become a key issue to be addressed to develop appropriate emission mitigation strategies in transportation sector. In this study, the influence of such evolution on on-road emissions was investigated based on a comprehensive dataset encompassing vehicle fleet composition, demographic, economic, and energy features from a representative small-medium automotive city in North America. The decoupling analysis was carried out to assess the dynamic linkage between environmental pressure exerted by the transportation sector and economic growth at both city level and national level in North America. We also developed an approach that supports the long-term traffic-related air pollutant prediction and investigated the potential influence on urban air quality. A sharp upward trajectory was observed in the quantity of SUVs from 2001 to 2018, gradually replacing the dominance of the quantity of four-door cars. There was a significant shift in the GHG emissions emitted from vehicle types used for passenger transport: emissions from SUVs and trucks rose by 374.0% and 69.3%, respectively, whereas emissions from four-door cars, two-door cars, station wagons, and vans all decreased. The changes in vehicle composition, along with the steady trend in GHG emissions from private fleet and decrease in on-road air pollutant concentrations found in Regina, were a response to the establishment of federal fuel economy standards and improved fuel economy. Relative decoupling was observed in aggregate for Regina and Canada in most of the years while both experienced economic downturns and increases in environmental pressure in the form of emissions from 2014 to 2015. The predicted results also demonstrate the high capability of XGboost machine learning algorithm in predicting on-road air pollutant concentrations of CO, PM_2.5, and NO_X.

Can Economic Growth and Environmental Protection Achieve a "Win-Win" Situation? Empirical Evidence from China

Achieving a "win-win" situation regarding economic growth and environmental protection has become a common goal for sustainable development in all countries around the world. As the world's largest developing country and the second largest economy, China has been striving to maintain economic growth while improving environmental quality to achieve its sustainable development goals. Applying the decoupling approach, a model widely used to quantify the relationship between the environment and the economy, this study analyzed the relationship between the economy and the environment, examining the decoupling performance of economic growth and environmental impacts in 30 Chinese provinces, autonomous regions, and municipalities to investigate whether economic growth and environmental protection have achieved a "win-win" situation. Nighttime light (NTL) data were used to measure the performance of economic growth. In addition, an environmental pressure index (EPI) assessment framework covering 6 primary and 11 secondary indicators was constructed to measure the environmental quality of China over time. First, NTL data proved to be a valid data source for assessing decoupling performance; second, environmental pressure at both the national and provincial levels significantly decreased during the study period; third, the relationship between the economy and the environment has been further improved, and economic growth and environmental protection have achieved a "win-win" situation. These findings offer an in-depth analysis of the decoupling of the economy and the environment in China and serve as a guide for future implementation strategies for sustainable development in various regions.

Revealing the Coupling Relationship between the Gross Ecosystem Product and Economic Growth: A Case Study of Hubei Province

The question of how to balance rapid economic growth with ecosystem pressures has become a key issue in recent years. Using the Tapio decoupling model, the spatial autocorrelation model, and the LMDI decomposition model, we analyzed the spatiotemporal variation in gross ecosystem product (GEP) in Hubei Province, studied the relationship between GEP and economic growth, and analyzed the driving factors of GEP variation. The results show that, during the period 2010–2019, the decoupling coefficient between GEP and economic growth in Hubei Province gradually decreased, while the decoupling relationship changed from weak decoupling to strong decoupling; this change is reflected not only in the decoupling index values of various cities but also in the number of changing cities, so this negative change should attract the attention of policy-makers. In addition, there is a significant local spatial autocorrelation in Hubei Province, mainly distributed in the northwest and southwest of the province, and the trend is becoming increasingly obvious. As the decoupling trend is negative, it is necessary to pay attention to local autocorrelation changes, especially in highly correlated cities, and take action to prevent the further exacerbation of such decoupling to maintain healthy economic and social development. Regarding the driving factors of GEP changes in Hubei Province, cities with strong decoupling and those with weak decoupling have certain differences, and different types of decoupling cities need to adopt different strategies to alleviate pressure on the ecological environment. Cities with a weak decoupling need to address the problem of pollutant emissions associated with industrial upgrading and the positive impact of scientific and technological innovation on the ecological environment. Cities with strong decoupling should not only address pollutant discharge but also improve the area of ecological land. From the perspective of urban development, the high-quality development trend of Wuhan, Yichang, Xiantao, Qianjiang, Xianning, and other cities shows a continuous trend of improvement. Ezhou, Jingzhou, Shennongjia, and other cities need to guard against the loss of ecosystems caused by economic growth.

The Effects of Broadband Infrastructure on Carbon Emission Efficiency of Resource-Based Cities in China: A Quasi-Natural Experiment from the "Broadband China" Pilot Policy

Resource-based cities (RBCs) face serious environmental pollution, and there are efforts to try to overcome those challenges by transforming industrial structure through investing in new technologies. Based on the panel data of 114 prefecture-level resource-based cities in China, this paper uses the difference-in-differences (DID) method to identify the effects of the “Broadband China” pilot policy on the carbon emission efficiency of resource-based cities. The results show that the “Broadband China” pilot policy has a significant effect on the improvement of carbon emission efficiency of resource-based cities, and the results are still valid after parallel trend test, PSM-DID estimation and placebo test. This study also finds that there are differences in the carbon emission efficiency of different locations and types of resource-based cities. In addition, the results of the mechanism analysis show that the “Broadband China” pilot policy can promote the improvement of carbon emission efficiency by promoting the upgrading of the industrial structure, the accumulation of human capital and the improvement of the level of urban innovation of resource-based cities. The findings provide a reference for China’s resource-based cities to develop the Broadband infrastructure, realize industrial upgrading, accumulate human capital and improve urban innovation level, and promote low-carbon transformation and improve carbon emission efficiency.

Deceleration of Cropland-N2O Emissions in China and Future Mitigation Potentials

Agricultural soils are the largest anthropogenic emission source of nitrous oxide (N2O). National agricultural policies have been implemented to increase crop yield and reduce nitrogen (N) losses to the environment. However, it is difficult to effectively quantify crop-specific and regional N2O mitigation priorities driven by policies, due to lack of long-term, high-resolution crop-specific activity data, and oversimplified models. Here, we quantify the spatiotemporal changes and key drivers of crop-specific cropland-N2O emissions from China between 1980 and 2017, and future N2O mitigation potentials, using a linear mixed-effect model and survey-based data set of agricultural management measures. Cropland-N2O emissions from China tripled from 102.5 to 315.0 Gg N yr-1 between 1980 and 2017, and decelerated since 1998 mainly driven by country-wide deceleration and decrease in N rate and the changes in sowing structure. About 63% of N2O emissions could be reduced in 2050, primarily in the North China Plain and Northeast China Plain; 83% of which is from the production of maize (33%), vegetables (27%), and fruits (23%). The deceleration of N2O emissions highlights that policy interventions and agronomy practices (i.e., optimizing N rate and sowing structure) are potential pathways for further ambitious N2O mitigation in China and other developing countries.

City- and county-level spatio-temporal energy consumption and efficiency datasets for China from 1997 to 2017

Understanding the evolution of energy consumption and efficiency in China would contribute to assessing the effectiveness of the government's energy policies and the feasibility of meeting its international commitments. However, sub-national energy consumption and efficiency data have not been published for China, hindering the identification of drivers of differences in energy consumption and efficiency, and implementation of differentiated energy policies between cities and counties. This study estimated the energy consumption of 336 cities and 2,735 counties in China by combining Defense Meteorological Satellite Program/Operational Line-scan System (DMSP/OLS) and Suomi National Polar-Orbiting Partnership/Visible Infrared Imaging Radiometer Suite (NPP/VIIRS) satellite nighttime light data using particle swarm optimization-back propagation (PSO-BP). The energy efficiency of these cities and counties was measured using energy consumption per unit GDP and data envelopment analysis (DEA). These data can facilitate further research on energy consumption and efficiency issues at the city and county levels in China. The developed estimation methods can also be used in other developing countries and regions where official energy statistics are limited.

Global low-carbon energy transition in the post-COVID-19 era

The COVID-19 pandemic has created significant challenges for energy transition. Concerns about the overwhelming emphasis on economic recovery at the cost of energy transition progress have been raised worldwide. More voices are calling for "green" recovery scheme, which recovers the economy while not compromising on the environment. However, limited academic attention has been paid to comprehensively investigating the implications of COVID-19 for global energy transition. This study thus provides a comprehensive analysis of the dynamics between energy transition and COVID-19 around the world and proposes a low-carbon energy transition roadmap in the post-pandemic era. Using energy data from the International Energy Agency (IEA), we first summarized and reviewed the progress of energy transition prior to COVID-19. Building on prior progress, we identified the challenges for energy transition during the pandemic from the perspectives of government support, fossil fuel divestment, renewable energy production capacity, global supply chain, and energy poverty. However, the pandemic also generates opportunities for global energy transition. We hence also identified potential opportunities for energy transition presented by the pandemic from the perspectives of price competitiveness, policy implementation efficiency, and renewable energy strengths. We further provided an in-depth discussion on the impact of current worldwide economic recovery stimulus on energy transition. Based on the identified challenges and opportunities, we proposed the post-pandemic energy transition roadmap in terms of broadening green financing instruments, strengthening international cooperation, and enhancing green recovery plans. Our study sheds light on a global low-carbon energy transition framework and has practical implications for green recovery schemes in post-pandemic times.

Accounting for the carbon emissions from domestic air routes in China

This study seeks to build a database of China's 413 main routes in 2018, which contains the carbon emission intensity of the leading aircraft types, the Climb/Cruise/Descent (CCD) carbon emissions of each airline and each route, and the probable emissions when the routes are straight. First, the Modified Fuel Percentage Method (MFPM) is applied to calculate the carbon emission intensity of main aircraft types at various distances. Next, the carbon emissions and the Revenue Passenger Kilometers of 413 routes and 40 airlines are calculated. Then the carbon emissions of the actual route and straight route are analyzed. Dali-Kunming and Joy Air have the most significant emission intensity among the routes and airlines. However, the excess emissions from the non-straight routes account for about 10.15% of the actual emissions.

Decoupling between ammonia emission and crop production in China due to policy interventions

Cropland ammonia (NH₃ ) emission is a critical driver triggering haze pollution. Many agricultural policies were enforced in past four decades to improve nitrogen (N) use efficiency while maintaining crop yield. Inadvertent reductions of NH₃ emissions, which may be induced by such policies, are not well evaluated. Here, we quantify the China's cropland-NH₃ emission change from 1980 to 2050 and its response to policy interventions, using a data-driven model and a survey-based dataset of the fertilization scheme. Cropland-NH₃ emission in China doubled from 1.93 to 4.02 Tg NH₃ -N in period 1980-1996, and then decreased to 3.50 Tg NH₃ -N in 2017. The prevalence of four agricultural policies may avoid ~3.0 Tg NH₃ -N in 2017, mainly located in highly fertilized areas. Optimization of fertilizer management and food consumption could mitigate three-quarters of NH₃ emission in 2050 and lower NH₃ emission intensity (emission divided by crop production) close to the European Union and the United States. Our findings provide an evidence on the decoupling of cropland-NH₃ from crop production in China and suggest the need to achieve cropland-NH₃  mitigation while sustaining crop yields in other developing economies.