[Optimization of Carbon Balance Zoning and Pattern in Beijing-Tianjin-Hebei Counties]

As an important "capital city economic circle," the determination of county carbon balance zones in the Beijing-Tianjin-Hebei counties is of great significance to its regional low-carbon development and achievement of the "dual-carbon" strategy. This study explores the spatial and temporal distribution patterns of carbon emissions and sequestration in the Beijing-Tianjin-Hebei counties from 2002 to 2020 based on the China carbon accounting database （CAD） and net ecosystem productivity （NEP） data. It further introduces the economy contributive coefficient （ECC） and ecological support coefficient （ESC） to analyze the energy efficiency and carbon sequestration capacity of the Beijing-Tianjin-Hebei counties, followed by the integration of the main functional areas （MFAs） of the territorial spatial planning. In this study, the carbon balance zoning of the Beijing-Tianjin-Hebei counties was optimized. The results showed that： ① In 2002, 2011, and 2020, the carbon emissions in the counties of Beijing and Tianjin showed a spatial distribution of "high in the southeast and low in the northwest," and the areas with high carbon sequestration were concentrated in the northwestern part of the counties of Zhangjiakou and Chengde. ② The ECC and ESC exhibited distinctive spatial heterogeneity in their spatial distribution, with ECC showing a decrease from Beijing to the surrounding area and the coefficient increasing with passing years. ESC showed a high spatial distribution in the north and low in the south, which showed improvement with passing years with the implementation of the sustainable development strategy. ③ The county carbon balance zoning after integrating the main function zoning was further refined into 16 sub-zones, where the low-carbon maintenance zone-key ecological function zone was mainly concentrated in the northwest, with a wider distribution but decreasing trend in quantity. Further, the distribution of the economic development zone-agricultural products and the carbon sink development zone-agricultural products main production zone was relatively stable, and the comprehensive optimization zone-agricultural products main production zone was mainly located in the southeastern part of the region, with a the number being the largest. These findings provides accurate data supporting the control of carbon emissions and economic development zoning in the Beijing-Tianjin-Hebei counties.