Persistent Coupling and Institutionally Driven Recovery in Colombian Municipal Solid Waste Management

Whether economic growth decouples from municipal solid waste (MSW) generation in upper-middle-income economies remains contested. We test the Waste Kuznets Curve and a disposal-to-recovery substitution effect using a 13-year panel of 1,101 Colombian municipalities, combining step-wise fixed-effects models with a non-parametric generalised additive model (GAM), a spatial autoregressive (SAR) check, and a selection-aware recovery model. We find no evidence of income-driven decoupling in landfilling. Once urban density and demographic structure are controlled, the income terms lose significance, the non-parametric estimate is predominantly monotonic, and density emerges as the main structural driver. Material recovery grows faster than disposal with income (relative substitution), but this signal is concentrated where recovery is measured—only 27% of municipalities report it, and coverage falls from 86% in metropolitan tiers to 19% in the rural periphery—so that once selection is corrected the recovery elasticity falls from about 5.9 to a non-significant 1.3. Rather than spontaneous decoupling, Colombia exhibits persistent coupling alongside an institutionally engineered, spatially unequal recovery capacity. Achieving SDG 12 therefore requires stratified policies that mandate consumption reduction in mature urban economies while subsidising shared circular infrastructure for historically neglected rural jurisdictions.