Managing the Climate Impact of Human Waste: A study to understand the impact of methane emissions from fecal sludge and potential abatement approaches

Sanitation systems contribute to anthropogenic methane emissions if the biological decomposition of human feces is facilitated by anaerobic technologies. Climate action to curb methane emissions can extend to the sanitation sector. This study, developed by USAID’s URBAN WASH activity, aimed to understand the current sources and drivers of methane emissions from sanitation systems in low- and middle-income country (LMIC) contexts. It found that the contribution of sanitation to methane emissions in LMIC contexts is significant and is likely to increase over time. Sanitation systems in urban sub-Saharan Africa contributed 3 to 5 percent to total anthropogenic methane emissions in 2020. This can grow to 8 percent in 2030, driven by the use of anaerobic containment and treatment technologies. Further, the study identified promising approaches and interventions for adoption in urban LMIC contexts and relevant evidence gaps, finding that abatement interventions (including technologies, service models, and behavior changes) already exist for specific contexts. However, some interventions need more experimentation to address evidence gaps. Innovation on technological gaps, guidelines, financing mechanisms, and measurement/monitoring tools can also support development of methane abating sanitation systems.