The booming dockless sharing bikes (DSBs) in China, as a new sharing economy business model, have attracted increasing public and academic attention after 2015. The impact of DSBs development on the stocks and flows of bikes and the resource and climate consequences of short-lived DSBs, however, remain poorly understood. In this study, we characterized the stocks and flows of both DSBs and regular private bikes in China from 1950 to 2020 and evaluated the carbon cost and benefit of booming DSBs. We found China's bike consumption and stock decreased slightly after a fast development from the late 1970s and then a peak in the mid-1990s, resulting in a relatively low ownership of approximately 0.3 unit per person and 70% of production being exported in recent years. Despite a temporal boost, the unsustainable development of DSBs may affect the bike industry in the long term, because of its skyrocketing market share (from less than 1% to 80%) and short lifetime. Nevertheless, DSBs development still leads to an overall climate gain in China, due to its higher stock efficiency and potentials to substitute more carbon intensive trips. We suggest an urgent need for more empirical studies on the use (e.g., substitution ratio for other transportation models) of DSBs in China and a necessity for better management of DSB development with efforts of all relevant stakeholders
