Long-Term Methane Emissions from Unmanaged Municipal Solid Waste Landfills in Baghdad under Population Growth Scenarios (2025–2100)

Municipal solid waste (MSW) landfills represent a major anthropogenic source of methane (CH₄), particularly in developing countries where unmanaged disposal practices remain prevalent. Baghdad, one of the fastest-growing cities in the Middle East, relies predominantly on landfill-based waste management systems with limited methane recovery infrastructure. This study presents a long-term quantitative assessment of methane emissions from unmanaged municipal solid waste landfills in Baghdad under multiple population growth and waste generation scenarios extending to the year 2100. Population projections were developed using exponential growth rates (2.5% and 3%), and per capita waste generation rates ranging from 1.0 to 1.5 kg/person/day were considered. Methane emissions were estimated using the IPCC 2006 default methodology for unmanaged landfill conditions, with emissions converted to CO₂-equivalent using a 100-year global warming potential (GWP100) of 28. Results indicate that cumulative methane emissions by 2100 may range from approximately 44 to 85 million tons of CH₄ depending on scenario assumptions. Under a moderate growth scenario (2.5% population growth and 1.25 kg/person/day), cumulative emissions are projected to reach approximately 55.7 million tons of CH₄, corresponding to nearly 1.56 gigatons of CO₂-equivalent. This magnitude is equivalent to roughly eight years of Iraq’s 2022 fossil fuel CO₂ emissions. Waste diversion strategies could significantly mitigate emissions, with a 30% landfill reduction avoiding approximately 0.47 gigatons CO₂-equivalent and a 50% reduction preventing nearly 0.8 gigatons by 2100. The findings highlight that landfill methane may represent a substantial yet under-addressed component of Iraq’s long-term climate mitigation challenge. Integrating waste sector reforms into national climate strategies could provide a meaningful pathway to support commitments under the Paris Agreement while delivering additional environmental co-benefits.