Impact of urbanization on terrestrial carbon storage loss in the Hohhot-Baotou-Ordos region, China: evaluating people-space interactions

Urbanization improves the living environment of billions of people but negatively impacts the local carbon cycle as it encroaches on ecosystems. We analyzed this dual effect of urbanization by quantifying linkages between several indicators - urbanization-induced terrestrial carbon storage loss (uTCSL), per capita urban area (PCUA), and urban land use efficiency (LCRPGR) - within the Hohhot-Baotou-Ordos (HBO) region in 1990-2100. Results show that the growth of 4.45 million urban residents and 420.70 km2 urban area led to a uTCSL of 815.74 GgC in the HBO region in 1990-2020. The uTCSL contributed to improving the urban crowding indicated by PCUA but was subject to LCRPGR. The PCUA decreased by -33.75 m2/person under high land use efficiency (LCRPGR<1) in 1990-2010. Although the PCUA increased by 23.59 m2/person from 2010 to 2020, it resulted in a 2.08-fold increase in uTCSL compared to 1990-2010, with each additional 1 m2 increase in PCUA being associated with carbon storage loss of 24.50 GgC. Our projections indicate that regulating LCRPGR twenty years before the urban population reaches its peak could benefit both uTCSL and PCUA. This study provides valuable insights for urban planning aligned with the UN 2030 Agenda, especially for arid and semi-arid cities.