Assessing socio-ecological fit of international environmental agreements and trade-embodied carbon flows

Global emissions embodied in trade (EET) constitute approximately one-third of total carbon emissions. Although countries combat environmental impacts via international cooperation, it is unclear whether these social efforts fit the ecological challenges. It is imperative to assess the fit between international environmental agreements (IEAs) and the EET. The article constructed global social-ecological networks during 1995-2021 for 189 countries. Based on the assumption of a Poisson-Binomial distribution, the networks were statistically verified by bipartite exponential random graph modeling (ERGM). To measure the degree of fit, the verified networks were tested in quadratic assignment procedure (QAP) correlation and logistic regression. Results: (1) Social-ecological fit of IEAs and EET decreased in the last 27 years from 0.313 to 0.138, with the effect of the ecological network on the social network weakened; (2) The relative importance of world countries in contribution to the fit outlines regional blocks; (3) An 8.681-year cycle of global fit was modeled and predicted for future shared socioeconomic pathway (SSP) scenarios until 2050; (4) The proposed ERGM-QAP method exhibits a computational advantage, applicable to other large-scale international fit problems. Social-ecological fit is interpreted as efficiency of environmental impact internalization, equity of international cooperation and effectiveness of human-nature interactions. Policy implications include accelerating IEA ratification, establishing a unified ETS within the top-contributing countries to global social-ecological fit, linking with other cap-andtrade systems and issuing common carbon credits to internalize carbon externalities.