Researchers have discovered that urban sewer networks are a significant source of methane, releasing between 1.18 and 1.95 million tons annually. This discovery challenges previous IPCC assumptions that sewer emissions were negligible, revealing a hidden climate cost in wastewater management. A new estimation tool, developed over 20 years of research, allows cities to quantify these emissions based on pipe size, flow, and temperature. Integrating this data into national greenhouse gas inventories is essential for accurate carbon accounting and developing targeted reduction strategies.
