Yang Li

Global climate governance increasingly relies on understanding the spatial mismatch between carbon emissions and ecosystem carbon sequestration capacity. As a critical regulating ecosystem service, carbon sequestration service flows exert substantial interregional spillover effects through spatial ecological interactions. However, existing research has largely focused on static supply–demand evaluations at regional scales, while the spatial flow processes and driving mechanisms of carbon sequestration service flows across cities remain insufficiently explored. This study quantified the supply, demand, and flows of carbon sequestration service flows across 333 prefecture-level administrative units in China from 2010 to 2024 using breakpoint–field strength models and spatial flow analysis. Furthermore, the XGBoost-SHAP model was adopted to detect the nonlinear driving mechanisms behind carbon sequestration service flows. The results showed that China’s carbon sequestration service flows presented a potential west-to-east linkage pattern, indicating a pronounced spatial mismatch between carbon sequestration supply areas and carbon emission demand areas. High-supply regions were predominantly distributed in western and northern China, whereas demand regions were concentrated in eastern coastal urban agglomerations. The total volume of carbon sequestration service flows first rose and then declined over the study period, while the radiation distance and spatial interaction of service flows continuously increased. The potential spatial linkage of carbon sequestration service flows were identified: Inner Mongolia-Beijing-Tianjin-Hebei, Yunnan–Guizhou–Pearl River Delta, and Northeast China/Sichuan-Xinjiang-eastern coastal urban agglomerations. XGBoost-SHAP analysis showed that PRE, DEM, TEMP, and GDP exhibited prominent main effects. PRE and TEMP had the strongest interaction, with DEM-TEMP and DEM-GDP showing relatively strong interactions compared with other variable pairs. The findings revealed the potential spatial linkage pattern of carbon sequestration service flows and offered scientific support for interregional ecological compensation and spatially coordinated carbon governance in China.

A rapid increase in the number of end-of-life (EoL) passenger vehicles has led to a large amount of waste plastics in China. However, the scale and efficiency of recycling resources from EoL vehicles still restricts the sustainable and healthy development of the automotive industry. The current behavior of automotive/recycling industry entities, as well as the strategy of waste management policymakers, may depend on the potential of total recyclable resources. To reveal such recycling potential of various plastic materials in EoL passenger vehicles, we predicted total EoL passenger vehicles in China from 2021 to 2030 (used the Weibull distribution) considering passenger vehicle ownership (estimated by the Gompertz model), quantified the demand for new passenger vehicles (estimated using its non-linear relationship with income level and passenger vehicle ownership), and assessed the recyclable plastics by categories and by provinces. The results show that (i) the annual average recycled plastic resources from EoL vehicles would exceed 2400 thousand t in 2030, more than 2.5 times in 2021, showing a great recycling potential; (ii) the differences among the three scenarios are relatively small, indicating that no matter the saturation level of passenger vehicles in China would be high or low, a rapid increase of recyclable plastic resources can be expected from 2021 to 2030; (iii) at the provincial level, a considerable gap between the potential of recycling plastic from EoL passenger vehicles and the regional processing capacity. Given such great potential and regional differences, the recycling policies should be applied in stages and consider the development level and recovery pressure in each region.

The contradiction between limited resources and rapid development in the automobile industry has been driving society to seek the supply of recyclable resources from End-of-Life Vehicles (ELVs). It has become an urgent need for vehicle recycling policymakers to have an overall understanding of the end-of-life (EoL) vehicle population, as well as for vehicle producers to note what and how they can benefit from ELV recycling. This paper estimated the potential population of EoL passenger vehicles, all recyclable resources from them, as well as the economic values of these recyclable resources. The results show that in 2030, with a lighter-weight trend of passenger vehicles, more than 26.3 million passenger vehicles will be retired with 19.1 million tons of recyclable steel and 6.2 million tons of plastics. The theoretical economic value of all recyclable resources will reach 101.3 billion yuan ($14.4 billion) in 2030, which is an average of approximately 2.4 thousand yuan ($341.8) for each EoL passenger vehicle. It is time for the vehicle producers to shift to a manufacturing mode considering such large potential of ELV recycling. The scenario analysis suggests that in the context of a light-weighting trend, ELV resource recovery in the future calls for improvement in the recycling and reuse technologies of plastics and rubbers.

With the acceleration of China’s urbanization process, the urban transportation problem has become increasingly serious. The rapid expansion of private vehicle ownership, in particular, has become one of the barriers to the realization of sustainable urban transition. This paper applied the Gompertz model to analyze the non-linear relationship between private vehicle ownership and per capita GDP in China using provincial data. In addition, we forecasted private vehicle ownership for 31 Chinese provinces for the period of 2019–2030 and predicted the time to reach the upper limit of 1000 people vehicle ownership of each province according to different scenarios. The main findings revealed that the number of private vehicles owned in China’s provinces was in line with “S”-shaped development and was currently in the process of accelerated growth. Under the scenario of an annual per capita GDP growth rate of 6%, China’s private vehicle ownership will reach 246 million, 375 million, and 475 million in 2020, 2025, and 2030, respectively. This indicates that China’s expansion of private vehicle ownership will generate significant challenges, such as on-road vehicle-related fossil fuel consumption, pollutant emissions, traffic congestion, and scrapped vehicle recycling. These issues will become increasingly prominent. In provinces such as Hubei, Hebei, Hunan, and other central provinces that have a 50–60% urbanization rate, the large potential for income promotion will significantly stimulate the increase in private vehicle ownership, and the upper limit of 1000 people vehicle ownership in each province will be reached in 2032, 2037, and 2046 with annual per capita GDP growth rates of 8%, 6%, and 4%, respectively.