Kick‐starting diffusion: Explaining the varying frequency of preferential trade agreements’ environmental provisions by their initial conditions

Most recent preferential trade agreements (PTAs) include environmental provisions. While a number of these environmental provisions remain rare and are incorporated in just a few PTAs, others are widely popular and are duplicated in more than 100 PTAs. We still lack a convincing explanation for this varying frequency. While the diffusion literature typically tries to explain how diffusion occurs, we investigate why certain provisions diffuse more often than others. We hypothesise that the initial conditions under which provisions first emerge determine the scope of their diffusion. Our results support this hypothesis and indicate that provisions originating from intercontinental agreements diffuse more often than others. At the same time, provisions first designed by economically powerful or environmentally credible countries are not related to more frequent occurrences of diffusion. These findings are of interest for the literatures on international institutions' design, interaction and diffusion.