Approximately 4.5 billion people lack access to safely managed sanitation globally, and 1 billion live in slums, often relying on anaerobic waste containment in pit latrines. Providing access to safely managed sanitation may lead to reduced GHG emissions and thus simultaneously address both Sustainable Development Goals. Here we measure cumulative GHG emissions of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) during the off-site composting of human waste to estimate scalable emission factors. We find that CH₄ emission factors are one to two orders of magnitude smaller than IPCC values for other excreta collection, treatment and disposal processes. After accounting for GHG emissions throughout the sanitation cycle, including transport, urine and compost end-use, the climate change mitigation potential is 126 kg of CO₂-equivalent per capita per year for slum inhabitants. If scaled to global slum populations, composting could mitigate 3.97 Tg CH₄ yr⁻¹, representing 13-44% of sanitation sector CH₄ emissions.

全球大约有45亿人无法获得经过安全管理的卫生设施，并且有10亿人居住在贫民窟中，这些人经常依靠坑厕中的厌氧废物控制。提供获得安全管理的卫生设施的途径可以减少温室气体的排放，从而同时实现两个可持续发展目标。在这里，我们测量了在人类粪便异地堆肥过程中二氧化碳（CO ₂），甲烷（CH ₄）和一氧化二氮（N ₂ O）的累积温室气体排放，以估算可扩展的排放因子。我们发现CH ₄排放因子比其他排泄物收集，处理和处置过程的IPCC值小一到两个数量级。在考虑了整个卫生周期（包括运输，尿液和堆肥的最终用途）的温室气体排放之后，贫民窟居民的气候变化缓解潜力为每年每人126千克CO ₂当量。如果扩大到全球贫民窟人口，堆肥可以减少3.97 Tg CH ₄  yr ^-1，占卫生部门CH ₄排放量的13-44％。