Not all waste trades alike : material archetypes in the gravity of global waste flows

International trade in waste and scrap has expanded rapidly, yet it remains underexplored in quantitative trade economics. This paper analyzes the determinants of waste flows across five major material categories (plastics, paper, glass, iron & steel, aluminum) using a gravity model enriched with bilateral tariff and non-tariff measures. Leveraging HS6 bilateral customs data for 2001–2022, we compare trade elasticities between waste and non-waste products within the same HS2 sectors to assess whether differences in trade patterns are material-specific. The results—robust to dynamic lead-lag specifications assessing systematic anticipation, and to heterogeneity analyses by income level—are consistent with three distinct archetypes: information-sensitive materials (plastics, aluminum), where technical NTMs display a pattern suggestive of certification mechanisms; complementarity-driven materials (paper), which exhibit inverted tariff elasticities reflecting technological lock-in in specialized recycling infrastructure; and commodity-like materials (glass, iron/steel), where trade responds conventionally to policy and geographic frictions. Our findings point to the value of tailoring trade and circular-economy measures to material characteristics, given the systematic differences observed across archetypes.