Global impervious surface area (ISA) has more than doubled over the last three decades, but the associated carbon emissions resulting from the depletion of pre-existing land carbon stores remain unknown. This study reports that carbon losses from biomass and topsoil (0–30 cm) due to global ISA expansion reached 46–75 Tg C per year over 1993–2018, accounting for 3.7–6.0% of concurrent human land-use change emissions. Emissions in Annex I countries are comparable to national greenhouse gas inventory reports, providing independent validation. The contrast between growing emissions in non-Annex I countries and declining ones in Annex I countries reflects an emissions evolution pattern dependent on economic development stage. This study reveals substantial contributions of ISA expansion to anthropogenic carbon emissions, impacting international carbon accounting and climate mitigation.

Linghua Qiu, Junhao He, Chao Yue, Philippe Ciais, Chunmiao Zheng