County-level carbon compensation zoning based on China's major function-oriented zones

Large but overlooked carbon inequalities among counties in China matter for the design of mitigation strategies. Here, we investigated the spatial heterogeneity of carbon inequality across 2236 county-level units nationwide from 2000 to 2020, refining carbon compensation zone types based on land functional zoning and estimating their carbon compensation values using a modified compensation model. Our results showed that China's carbon inequality consistently exceeded the cautionary threshold of 0.4 on the Gini coefficient. Significant spatial variations in carbon intensity were observed, notably concentrated in the North China Plain and Yangtze River Delta, indicating a pronounced core-periphery structure. The nonlinear relationships among carbon emission pressure (CEP), land use intensity (LUI), economy contributive coefficient (ECC), and ecological support coefficient (ESC) were identified. CEP and ECC posed initial increases followed by decreases with LUI, while ESC decreased with increasing LUI. The inverted U-curve between ECC and CEP suggested that most county-level cities have yet to reach the decoupling tipping point. Based on spatial comparative advantage, we identified 625 payment zones, 666 equilibrium zones, and 945 recipient zones, culminating in nine types of carbon compensation zones aligned with land functional objectives. Our study provides a new county-level carbon compensation zoning approach that can achieve carbon equity.