Abstract The municipality of Belém, Brazil, is presenting continuous growth of its urbanized area and its vehicle fleet in recent decades. These changes are also associated with reductions in tree coverage areas and have increased local CO2 emission. Henceforth, there is a need to understand the dynamics of regional greenhouse gases (GHG) emission in an integrated manner. The study aimed to elaborate a carbon balance between the emission from public transportation and sequestration by urban vegetation in the municipality of Belém. Thus, carbon balance was performed by dimensioning bus routes and the carbon sequestration and also estimated through a semiautomatic classification of high-resolution satellite images and literature references. Thus, there was a sequestration potential of 5.117,82 tons of carbon per year, while public transportation busses’ emissions corresponded to 146.889,61 tons of carbon/year. Thereby, carbon sequestration accounted for 3.48% of CO2 emission from the public transportation system. Lastly, it was possible to notice the need to implement integrated policies to acquire higher values of CO2 emissions’ mitigation in the municipality of Belém.