Limited terrestrial carbon sinks and increasing carbon emissions from the Hu Line spatial pattern perspective in China

China's commitment to achieving the goal of carbon peak and carbon neutrality (CPCN) has attracted worldwide attention, and the efforts made by China are critical to realization of the 1.5 °C temperature control objective of the 2015 Paris Agreement. However, it is unclear whether long-term spatiotemporal changes in China's carbon emissions and carbon sinks exhibit specific spatial patterns, such as the Hu Line, which might affect China's future policymaking. Based on the emission factor, inventory, and eddy covariance methods, this study calculated China's carbon emissions (2003–2018) and terrestrial carbon sinks (2003–2020). Results showed that the increase in carbon sinks is limited in comparison with the increase in carbon emissions, and that the carbon sequestration ratio remains deficient and generally maintained at around 10 %. The spatial pattern of carbon emissions and carbon sinks showed an unbalanced state across the Hu Line, mainly reflected in accelerated increase in both the carbon emission rankings and the proportion of emissions to China's total carbon emissions of provinces on the northwestern side of the Hu Line. Despite this, the gross domestic product (GDP) rankings of those provinces have not improved substantially, whereas provinces on the southeastern side of the Hu Line have contributed most to China's GDP and terrestrial carbon sinks. The findings of this study improve understanding of the spatiotemporal relationship between carbon emissions and terrestrial carbon sinks in China, and represent alternative insights that could support adjustment of carbon-related policies and promote realization of CPCN in China.