Expanding waste collection without organic diversion increases methane emissions: scenario evidence from Ouagadougou, Burkina Faso

Programmes across the Sahel generally assume that expanding formal waste collection improves environmental performance. This study shows that the assumption does not always hold. Ouagadougou, Burkina Faso, generates about 2,600 t/day of household solid waste, 58% of it organic, while formal collection reaches fewer than 44% of households. We developed four intervention scenarios for 2030 and 2032. Increasing collection coverage from 44% to 80% without expanding organic diversion increases methane-driven emissions by about 140 kt CO₂-eq/year (19%) relative to business as usual. The increase results from a change in disposal conditions rather than waste generation. Moving organic waste from shallow uncontrolled dumping (IPCC methane correction factor, MCF = 0.6) to a managed landfill without gas capture (MCF = 1.0) raises the citywide blended MCF from 0.78 to 0.92, increasing methane generation. Combining the same increase in collection coverage with organic diversion reduces emissions by about 148 kt CO₂-eq/year (20%). Implementing all four intervention pillars reduces emissions by about 286 kt CO₂- eq/year (38%) and creates an estimated 1,250–2,100 jobs. The analysis combines seven-fraction waste characterisation, Tapio decoupling (ε = 0.97, no absolute decoupling), STIRPAT decomposition (population β = 0.87; affluence β = 0.53), and an IPCC Tier 1 recovery-gap assessment identifying a 56- percentage-point organic recovery gap and about 1,330 t/day of recoverable material. Five other Sahelian cities report collection coverage below the Sub-Saharan African average, suggesting that these conditions extend beyond Ouagadougou. Expanding waste collection should therefore be accompanied by organic waste diversion to avoid increasing landfill methane emissions.