Spatial–Temporal Differentiation and Cross-Border Spillover Mechanisms of Green Development in Eurasia

Green development is a principal pathway for implementing the United Nations’ sustainable development agenda. As a critical region for global green transition, existing studies focusing on Eurasia still lack a systematic continent-scale characterization of the spatial–temporal differentiation of green development and its driving mechanisms, particularly regarding the direction and cross-country heterogeneity of cross-border spillovers. This study constructs an evaluation system to assess the green development levels of 60 Eurasian countries from 2005 to 2020 and analyze their spatial pattern. A two-way fixed-effects spatial Durbin model with partial-effect decomposition identifies the driving factors, and country-level shock simulations depict the structure of spillovers across countries. The results show that (1) green development scores exhibit significant and continuously intensifying spatial agglomeration; (2) green development of Eurasia displays strong endogenous spatial dependence (ρ = 0.555, p < 0.001), and an asymmetric spillover pattern consistent with a spread–backwash interpretation, with spillover directions varying across drivers and countries occupying heterogeneous positions in receiving and emitting spillovers; and (3) country-level shock simulations suggest that, under a common one-unit shock to all explanatory variables, approximately 81% of the simulated total response is retained domestically, while the remaining 19% spills over to other countries. Theoretically, the study applies the spread–backwash perspective as an interpretive lens to link driver-specific indirect effects with country-level asymmetries in received and emitted spillovers. From a policy perspective, green development in Eurasia should be implemented according to each country’s endowment and complemented by cross-border policy coordination tailored to countries’ positions in receiving and transmitting spillovers. Collaborative river-basin governance and regional compensation mechanisms could help enhance potential positive spillovers, mitigate potential cross-border costs, and promote the overall green transformation of the region.