Examining spatio-temporal variations in carbon budget and carbon compensation zoning in Beijing-Tianjin-Hebei urban agglomeration based on major functional zones

Research on the carbon budget and zoning for carbon compensation in major functional zones(MFZs)is important for formulating strategies for low-carbon development for each functional zone,promoting the collaborative governance of the regional ecological environment,and achieving high-quality development.Such work can also contribute to achieving peak emissions and carbon neutrality.This paper constructs a theoretical framework for the carbon budget and carbon compensation from the perspective of the MFZ,uses 157 county-level units of the Beijing-Tianjin-Hebei urban agglomeration(BTHUA)as the study area,and introduces the concentration index,normalized revealed comparative advantage index,and Self Organizing Mapping-K-means(SOM-K-means)model to examine spatio-temporal variations in the carbon budget and carbon compensation zoning for the BTHUA from the perspective of MFZs.The authors propose a scheme for the spatial minimization of carbon emissions as oriented by low-carbon development.The results show that:(1)From 2000 to 2017,the carbon budget exhibited an upward trend of volatility,its centralization index was higher than the“warning line”of 0.4,and large regional differences in it were noted on the whole.(2)There were significant regional differences in the carbon budget,and carbon emissions exhibited a core-periphery spatial pattern,with a high-value center at Beijing-Tianjin-Tangshan that gradually decreased as it moved outward.However,the spatial pattern of carbon absorption tended to be stable,showing an inverted“U-shaped”pattern.It was high in the east,north,and west,and was low in the middle and the south.(3)The carbon budget was consistent with the strategic positioning of the MFZ,and the optimized development zone and key development zone were the main pressure-bearing areas for carbon emissions,while the key ecological functional zone was the dominant zone of carbon absorption.The difference in the centralization index of carbon absorption among the functional zones was smaller than that in the centralization index of carbon emissions.(4)There were 53 payment areas,64 balanced areas,and 40 obtaining areas in the study area.Nine types of carbon compensation zones were finally formed in light of the strategic objectives of the MFZ,and directions and strategies for low-carbon development are proposed for each type.(5)It is important to strengthen research on the carbon balance and horizontal carbon compensation at a microscopic scale,enrich the theoretical framework of regional carbon compensation,integrate it into the carbon trading market,and explore diversified paths for achieving peak emissions and carbon neutrality.

Driving factors and spatiotemporal effects of environmental stress in urban agglomeration: Evidence from the Beijing-Tianjin-Hebei region of China

Environmental stress is used as an indicator of the overall pressure on regional environmental systems caused by the output of various pollutants as a result of human activities. Based on the pollutant emissions and socioeconomic databases of the counties in Beijing–Tianjin–Hebei region, this paper comprehensively calculates the environmental stress index(ESI) for the urban agglomeration using the entropy weight method(EWM) at the county scale and analyzes the spatiotemporal patterns and the differences among the four types of major functional zones(MFZ) for the period 2012–2016. In addition, the socioeconomic driving forces of environmental stress are quantitatively estimated using the geographically weighted regression(GWR) method based on the STIRPAT model framework. The results show that:(1) The level of environmental stress in the Beijing–Tianjin–Hebei region was significantly alleviated during that time period, with a decrease in ESI of 54.68% by 2016. This decrease was most significant in Beijing, Tangshan, Tianjin, Shijiazhuang, and other central urban areas, as well as the Binhai New Area. The level of environmental stress in counties decreased gradually from the central urban areas to the suburban areas, and the high-level stress counties were eliminated by 2016.(2) The spatial spillover effect of environmental stress increased further at the county scale from 2012 to 2016, and spatial locking and path dependence emerged in the cities of Tangshan and Tianjin.(3) Urbanized zones(development-optimized and development-prioritized zones) were the major areas bearing environmental pollution in the Beijing–Tianjin–Hebei region in that time period. The ESI accounted for 65.98% of the whole region, where there was a need to focus on the prevention and control of environmental pollution.(4) The driving factors of environmental stress at the county scale included population size and the level of economic development. In addition, the technical capacity of environmental waste disposal, the intensity of agricultural production input, the intensity of territorial development, and the level of urbanization also had a certain degree of influence.(5) There was spatial heterogeneity in the effects of the various driving factors on the level of environmental stress. Thus, it was necessary to adopt differentiated environmental governance and reduction countermeasures in respect of emission sources, according to the intensity and spatiotemporal differences in the driving forces in order to improve the accuracy and adaptability of environmental collaborative control in the Beijing–Tianjin–Hebei region.