This paper documents new stylized facts on the formation, design, and participation of international environmental agreements using data from the International Environmental Agreements Database Project (IEADB) for the period 1980–2023. We describe trends in treaty formation, coalition size, duration, and depth, highlighting a shift from new agreements toward the amendment and expansion of existing treaty lineages. Treaty characteristics vary systematically across environmental domains and geographic scope, with regional agreements exhibiting deeper commitments but more limited participation.

A central contribution of the paper is to link environmental treaties to international trade agreements. Combining IEADB data with information on preferential trade agreements and their environmental provisions, we document a growing integration of environmental objectives into trade policy. The results provide a data-driven foundation for future research on treaty effectiveness and policy interaction.