Shared micromobility systems (SMSs) have witnessed rapid growth in recent years, offering new environmentally-friendly mobility options aimed at reducing energy consumption. To gain a deeper understanding of the environmental impact of SMSs, this chapter compares the potential for carbon emission reductions from dockless shared bikes and e-bikes in three Chinese cities at varying stages of economic development (i.e., Binjiang, Wucheng, and Xiangshan) using extensive user-generated trip data. The results show that shared bikes and e-bikes in these cities reduce 41.51 and 31.84 tonnes of CO2 emissions over the course of a week, respectively. The carbon reduction per trip for shared e-bikes is 155.11 g of CO2, which is higher than that of shared bikes (132.03 g). The majority of carbon emissions reductions are attributed to the substitution of car trips, although shared e-bikes also contribute to increased carbon emissions by replacing public transport and walking trips. Carbon emission reductions exhibit spatiotemporal variability. Spatially, the reductions are concentrated in the central areas of Wucheng and Xiangshan, while Binjiang, a more economically dynamic city, shows more dispersed emission reductions. From a temporal perspective, the patterns of carbon reductions follow typical usage trends for SMSs. Dining and shopping-related trips contribute the most to carbon reductions in all cities. Binjiang experiences greater reductions from transfer and work-related trips, while shared bike trips for home and schooling purposes in Wucheng lead to more substantial carbon reductions. This analysis provides a clearer understanding of the environmental impact of SMSs in different urban contexts, offering insights that can inform transport planning strategies aimed at achieving carbon neutrality in cities.