A new UNU science talk on June 10, 2026 will present research showing that wastewater treatment plants emit more fossil CO2 than previously accounted for. The 2006 IPCC guidelines assumed all carbon in wastewater was modern, but radiocarbon analysis proves a fraction is fossil-derived, increasing estimated greenhouse gas emissions by 13% to 23% depending on energy recovery systems. The research also finds that much fossil carbon stays in biosolids after digestion, creating a potential carbon sequestration opportunity. This work contributed to the IPCC's 2019 guideline updates and highlights the need for better carbon accounting in water infrastructure. The talk is open to the public and relevant for anyone tracking real decarbonization in waste and water sectors.
