Revealing hidden methane mitigation opportunities from legacy dumping and landfilling of municipal solid waste in rural China

Methane (CH₄) emissions from landfills and dumpsites pose a challenge to climate change mitigation, particularly in rural areas with limited waste management infrastructure. This study provides a comprehensive spatiotemporal assessment of CH₄ emissions from municipal solid waste disposal across 31 Chinese provinces from 1950 to 2050, focusing on the long-term and often overlooked contributions of rural dumping. Findings reveal that cumulative CH₄ emissions from rural dumpsites (51.9 Tg) exceed those from rural landfills (33.4 Tg) and urban dumpsites (47.0 Tg). A large portion of future emissions will originate from historically dumped waste. A scenario-based cost-benefit analysis indicates that prioritizing mitigation in rural areas and dumpsites could reduce CH₄ by 7.4 Tg and generate net economic benefits of 13.0 billion USD by 2050. Delayed action could forfeit more than half of these gains. These results highlight the urgency of rural-focused actions to tackle legacy emissions and achieve long-term environmental and economic gains.