Decoupling without outsourcing? How China's consumption-based CO2 emissions have plateaued

Fall into the pseudo-decoupling trap: Type identification, trend characterization and solution path of carbon decoupling trap in urban agglomerations of China

This study investigates the stability and sustainability of carbon decoupling in urban agglomerations across China, where the strong coupling between economic growth and carbon emissions poses significant challenges. Despite efforts in energy conservation and emission reduction, urban agglomerations have seen unsatisfactory results. By analyzing the real-pseudo decoupling states in 19 urban agglomerations from 2007 to 2020, the objective of this study is to identify the type and trend characteristics of carbon decoupling traps and to propose solution paths for maintaining decoupling stability. Major Findings: (1) The decoupling state exhibits volatility and instability in urban agglomerations, making them susceptible to decoupling traps. (2) Most urban agglomerations remain un-decoupled, with a few cities achieving real decoupling and gradually shifted from northeast to southeast, while pseudo-decoupling and un-decoupled cities consistently cluster in the southwest and northwest regions. (3) Real-pseudo decoupling is driven by a combination of endogenous and exogenous factors, with energy structure, population density, and environmental regulation intensity emerging as pivotal influencers. (4) Geographical factors exhibit both commonalities and variations in their impact on real-pseudo decoupling. By identifying real-pseudo decoupling states and their driving factors, this study proposes strategic solution paths to overcome carbon constraints and achieve stable decoupling in urban agglomerations, contributing to the broader goals of sustainable economic and environmental development.

Interbasin trade worsens the state of freshwater fish biodiversity in China

Human economic activities severely threaten freshwater fish biodiversity in different river basins. Trade makes the impact more mysterious and complex and confounds local efforts to protect freshwater biodiversity. To investigate the relationship between trade and freshwater fishes, we developed a river-basin economic transaction model that is applied to mainland China, home to 9% of the world's freshwater fish species. Here, we show that interbasin trade induced by final demand contributes 74% of the threats to China's freshwater fish biodiversity. Economically developed river basins (e.g., the Huaihe River) are the main beneficiaries of interbasin trade at the cost of biodiversity deterioration in economically underdeveloped river basins (e.g., the upper Pearl River), especially when trade occurs between distant basins. Our findings highlight the significance of the shift in governance from administrative divisions to river basins and control measures in different stages of economic supply chains to mitigate freshwater fish biodiversity threats.

Market-based solution in China to finance the clean from the dirty

Financial incentives play a key role in promoting renewable energy investments that can help China achieve the 'dual carbon' goal. The national emissions trading scheme (ETS) and the renewable energy portfolio standard (RPS) are two existing market-based policy instruments that can generate stable expected returns for low-carbon projects. This paper studies the interactive distribution effects of these two market-based instruments. We use the micro-level thermal power plant data to investigate the abatement effects of the national ETS, in which the details show that the existing rate-based ETS will result in higher negative impacts on power units, whose installed capacities are smaller than 400 MW. The interactive distribution effects between the two markets will occur when the permit allocation standards of the national ETS become stricter than the existing ones. Provinces in Eastern China and Northern China will face high pressure on costs in both ETS and RPS markets. When the levels of the permit allocation standards are set as 70% of the existing ones and the carbon price is assumed to be 200 yuan/ton in 2030, the annual market size of the national ETS will be nearly 100 billion yuan, and the annual market size is predicted to be 250 billion yuan. In the existing rate-based national ETS, the China Certified Emission Reduction (CCER) mechanism will have an offsetting effect, which should be taken into serious consideration during the policy-making processes in the future.

Multi-scenario reduction pathways and decoupling analysis of China's sectoral carbon emissions

To achieve its goal of carbon emissions peak and neutrality, China requires synergistic efforts across all sectors. In this study, three scenarios-baseline, policy, and green low-carbon-were developed to explore the pathways for China's emissions reduction across sectors from 2020 to 2060, and the timing of decoupling economic growth from CO2. The results showed that, under these scenarios, China's carbon emissions peak in 2030, 2026, and 2025, with strong decoupling time, lagged one year behind peak attainment. The agriculture, forestry, livestock, and fishing (AFH) and mining and quarrying (MQ) sectors would be the first to achieve a carbon peak. Under all three scenarios, all of the other sectors-with the exception of electricity, gas, and water production and supply (EGW)-will achieve a carbon peak by 2030. Therefore, policymakers should set carbon peak goals based on sector characteristics and ensure energy security in the process of achieving carbon neutrality.

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.

Evolutionary characteristics of global offshore carbon emissions network and responsibility allocation of emissions reduction

Offshore carbon emissions from the international shipping trade are significant contributors to climate change. Based on the complex shipping trade networks, offshore carbon emissions are correlated rather than independent, and allocating responsibility for reducing emissions does not depend solely on the amount but on linkages. We use the global container shipping data covering more than 98% of routes from 2015 to 2020 to calculate the offshore carbon emissions from shipping. Subsequently, we construct an offshore carbon emissions network based on the shipping routes and emissions to identify the evolutionary tendency of network and clarify emissions reduction responsibilities by considering equity and efficiency. We discover that global offshore carbon emissions present a complicated network structure dominated by developed countries and large economies. Countries on the same continent or within the same economic organizations have closer and more frequent carbon correlations. Greater responsibilities should be allocated to countries who are at the center of the network.

Exploring the coupling and decoupling relationship of urbanization and carbon emissions in China

Burgeoning urbanization is a defining challenge for global carbon emissions mitigation in the coming decades. In this context, achieving low-carbon urbanization remains an urgent issue that demands prompt solutions. The coupling and decoupling relationships between urbanization and carbon emissions play an important role in the coordination of urbanization development and carbon emissions reduction, which has rarely been explored in existing studies, especially in China at the county level. To address this gap, the coupling and decoupling relationship between the urbanization level (UL) and carbon emissions density (CED) was explored using an improved coupling degree model and the Tapio decoupling method in China at the county level from 2000 to 2020. The results showed that the UL and CED of China both exhibited increasing trends, and the spatial distribution was quite similar, with the UL increasing from 0.018 in 2000 to 0.028 in 2020 and the CED increasing from 95.163 ton/km2 in 2000 to 295.746 ton/km2 in 2020. The spatial distribution of hotspots in the UL change differed with time, whereas that in the CED change was relatively stable. However, both of them were concentrated in eastern China. The coupling degrees of the UL and CED in China were 0.348, 0.355, 0.369, 0.370, and 0.338 in 2000, 2005, 2010, 2015, and 2020, respectively, with the moderately unbalanced type (>35%) being dominant at the county level and mainly scattered in eastern China. The changes in the spatial distribution patterns of the 10 subcategories were quite limited, with the systematically balanced type being dominant (89%). The decoupling types of the UL and CED during 2000-2005, 2005-2010, and 2010-2015 were weak decoupling, while those in 2015-2020 were expansive negative decoupling. At the county level, the most significant transition occurred between expansive negative decoupling, strong decoupling, and strong negative decoupling. The proportion of strong decoupling type counties peaked in 2015-2020 (70.86%), whereas that of the strong negative decoupling type counties remained high (17.55%), scattering the country. These findings can advance policy enlightenment of low-carbon urbanization and green development for China against the backdrop of "30·60 dual carbon" goal.

Tracing metal footprints via global renewable power value chains

The globally booming renewable power industry has stimulated an unprecedented interest in metals as key infrastructure components. Many economies with different endowments and levels of technology participate in various production stages and cultivate value in global renewable power industry production networks, known as global renewable power value chains (RPVCs), complicating the identification of metal supply for the subsequent low-carbon power generation and demand. Here, we use a multi-regional input-output model (MRIO) combined with a value chain decomposition model to trace the metal footprints (MFs) and value-added of major global economies' renewable power sectors. We find that the MFs of the global renewable power demand increased by 97% during 2005-2015. Developed economies occupy the high-end segments of RPVCs while allocating metal-intensive (but low value-added) production activities to developing economies. The fast-growing demand for renewable power in developed economies or developing economies with upper middle income, particularly China, is a major contributor to the embodied metal transfer increment within RPVCs, which is partly offset by the declining metal intensities in developing economies. Therefore, it is urgent to establish a metal-efficient and green supply chain for upstream suppliers as well as downstream renewable power installers for just transition in the power sector across the globe.

The Polarizing Trend of Regional CO2 Emissions in China and Its Implications

CO2 emissions are unevenly distributed both globally and regionally within nation-states. Given China's entrance into the new stage of economic development, an updated study on the largest CO2 emitter's domestic emission distribution is needed for effective and coordinated global CO2 mitigation planning. We discovered that domestic CO2 emissions in China are increasingly polarized for the 2007-2017 period. Specifically, the domestically exported CO2 emissions from the less developed and more polluting northwest region to the rest of China has drastically increased from 165 Mt in 2007 to 230 Mt in 2017. We attribute the polarizing trend to the simultaneous industrial upgrading of all regions and the persistent disparity in the development and emission decoupling of China's regions. We also noted that CO2 emissions exported from China to the rest of the world has decreased by 41% from 2007 to 2017, with other developing countries filling up the vacancy. As this trend is set to intensify, we intend to send an alarm message to policy makers to devise and initiate actions and avoid the continuation of pollution migration.

What drives the decoupling progress of China's civil aviation transportation growth from carbon emissions? A new decomposition analysis

Civil aviation carbon emission reduction is an inevitable requirement for achieving sustainable social development. Realizing the continuous expansion of air transportation scale while reducing the impact on the environment is particularly important. Therefore, it is necessary to accurately understand the relationship between civil aviation carbon emissions and the industry development. This study established a civil-aviation-pointed Tapio decoupling model to identify the decoupling state between transportation scale added and carbon dioxide emissions in China's civil aviation sector. The index decomposition analysis method is further applied to decompose the factors influencing the changes in decoupling states. The empirical study generated three important findings. Firstly, the overall carbon emissions in the civil aviation sector are still growing, while the energy intensity has a tendency to fluctuate and decrease. Secondly, the relationship between carbon emissions and transport turnover is dominated by the expansive coupling, that is, the development of the civil aviation sector is still at the cost of the growth of energy consumption. Nevertheless, the overall decoupling stability is unstable, and the decoupling state is likely to be changed by many external factors. Thirdly, the energy intensity decoupling effect and industry structure decoupling effect are the main reasons for civil aviation carbon decoupling. Meanwhile, the improvement of national economic level during the research period is the dominant negative factor that restrains the carbon decoupling of the civil aviation sector.

Global spatio-temporal change assessment in interregional water stress footprint in China by a high resolution MRIO model

Developing effective strategies to alleviate increasing water stress in China requires an understanding of how consumption and production drive water stress footprints (WSF) at a high resolution and multiple spatial and temporal scales. However, current Chinese multi-regional input-output (CMRIO) models have limited resolution. Here, we build a high-resolution international MRIO model covering 31 Chinese provinces, 163 sectors, to address this issue, and then analyze the impact of changes in China's interprovincial and international trade patterns on the WSF from 2012 to 2017. We find that China's water stress embodied in inter-provincial trade has increased year after year, to 5606 km³ H₂O-eq in 2017, exceeding 50 % of the total domestic footprint. Domestic water stress transfer is most apparent in the outsourcing of water stress from eastern coastal regions to Central and Western regions, with the top interregional supply chain paths mainly associated with the demand of processed rice and tobacco products. China has transformed into a net exporter of water stress in 2017, with water stress exports to developing countries accounting for 54 % of total exports, up from 51 % in 2012. With deepening globalization, trade between China and developing countries has boosted bilateral economic development, while also exacerbating water stress in China. In addition to agricultural cultivation, industrial products such as plastics and steel exported to meet international industries further contribute to water stress in Northern China. Further identify hotspots of water stress consumption is needed to prioritize actions to relieve regional water stress in a more effective manner, and our study can provide key information.

Peaking Industrial CO2 Emission in a Typical Heavy Industrial Region: From Multi-Industry and Multi-Energy Type Perspectives

Peaking industrial carbon dioxide (CO2) emissions is critical for China to achieve its CO2 peaking target by 2030 since industrial sector is a major contributor to CO2 emissions. Heavy industrial regions consume plenty of fossil fuels and emit a large amount of CO2 emissions, which also have huge CO2 emissions reduction potential. It is significant to accurately forecast CO2 emission peak of industrial sector in heavy industrial regions from multi-industry and multi-energy type perspectives. This study incorporates 41 industries and 16 types of energy into the Long-Range Energy Alternatives Planning System (LEAP) model to predict the CO2 emission peak of the industrial sector in Jilin Province, a typical heavy industrial region. Four scenarios including business-as-usual scenario (BAU), energy-saving scenario (ESS), energy-saving and low-carbon scenario (ELS) and low-carbon scenario (LCS) are set for simulating the future CO2 emission trends during 2018−2050. The method of variable control is utilized to explore the degree and the direction of influencing factors of CO2 emission in four scenarios. The results indicate that the peak value of CO2 emission in the four scenarios are 165.65 million tons (Mt), 156.80 Mt, 128.16 Mt, and 114.17 Mt in 2040, 2040, 2030 and 2020, respectively. Taking ELS as an example, the larger energy-intensive industries such as ferrous metal smelting will peak CO2 emission in 2025, and low energy industries such as automobile manufacturing will continue to develop rapidly. The influence degree of the four factors is as follows: industrial added value (1.27) > industrial structure (1.19) > energy intensity of each industry (1.12) > energy consumption types of each industry (1.02). Among the four factors, industrial value added is a positive factor for CO2 emission, and the rest are inhibitory ones. The study provides a reference for developing industrial CO2 emission reduction policies from multi-industry and multi-energy type perspectives in heavy industrial regions of developing countries.