Carbon Sinks and Carbon Emissions Discrepancies at Fine Scale for Mega Cities in China

Assessing discrepancies between carbon sinks and emissions at the urban scale is crucial for evaluating progress toward carbon neutrality in Chinese cities. Here we developed an integrated model to conduct a high-resolution (250-m, monthly) assessment of carbon emissions and sinks in three mega Chinese city clusters: Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta. Our results precisely depicted the seasonal patterns of net carbon emissions (NCE, defined as the difference between carbon emissions and sinks) and various urban carbon dynamics, such as urban villages, industrial zones, green parks. Nearly half of the 48 cities exhibited NCE exceeding 1000 gC∙m−2∙a−1, while only 5 cities function as carbon sinks. The percentage of carbon sinks to emissions in three city clusters ranged from 13–32%, highlighting a significant gap toward achieving carbon neutrality. Our model provides superior resolution and intricate spatial details, offering valuable insights for urban afforestation and emission mitigation policies.