Study Finds Climate TRACE Underestimates Vehicle CO2 Emissions
A recent study has found that Climate TRACE, a global emissions inventory using machine-learning methods, underestimates vehicle CO2 emissions compared to the Vulcan Project. Vulcan uses government-sourced traffic, energy, and infrastructure data to produce high-resolution on-road CO2 estimates. The study highlights methodological mismatches between the two systems, including differences in activity proxies, emission-factor assumptions, and spatial allocation algorithms. These discrepancies can significantly impact city-scale policy and verification questions, especially when one inventory is used as a baseline for mitigation tracking. The study suggests that while Climate TRACE's approach is innovative, it may not be as reliable for urban on-road allocation as Vulcan. 
