How do lower income countries (LICs) shape multilateral environmental agreements’ (MEAs) dynamism, i.e., the introduction of new legal commitments into treaty frameworks? I argue that LICs often have incentives to pursue treaty amendments that strengthen environmental commitments. However, when LICs are more deeply integrated into global trade and reliant on environmentally intensive exports, structural constraints may discourage support for MEA adaptation. In such contexts, trade dependence can undermine environmental ambition, making MEAs with a larger number of LIC members less likely to be dynamic. Drawing on the most comprehensive quantitative dataset of MEAs since 1945, the analysis shows how global economic integration conditions environmental governance and highlights persistent barriers to treaty dynamism in the Global South.