Methane emissions from the world’s largest cities have unexpectedly risen 6% since 2019, according to satellite data, suggesting that some sources are unaccounted for.
The study, led by University of Michigan researchers, found that urban emissions of methane are rising faster than ‘bottom-up’ accounting estimates anticipated.
The discrepancy was found with satellite measurements of methane over 92 major cities around the world. For 72 of the cities, there was sufficient data to track changes in methane emissions between 2019 and 2023. Overall, global urban methane emissions in 2023 were 6% higher than 2019 levels and 10% higher than 2020 levels, although they tended to decrease in European cities.
In contrast, accounting methods that tally emission estimates of individual methane sources suggest that urban methane emissions have only risen between 1.7% and 3.7% since 2020.
The study included over half of the C40 network, a group of 97 cities around the world aiming to reach net zero emissions...