Unfolding the effectiveness of ecological restoration programs in enhancing vegetation carbon sinks across different climate zones in China

Evaluating the vegetation carbon sink capacity across different climate zones in China is vital for optimizing the ecological restoration management practices and achieving double carbon goals. Based on the land cover and net primary productivity, along with a comprehensive literature review, we developed a vegetation carbon sink (VCS) estimation model at a 500 m × 500 m grid resolution to evaluate the carbon sink capacity of vegetation in China from 2001 to 2020. Results showed that the mean annual VCS_rate in China was 0.23 Mg C·ha⁻¹·yr⁻¹, with the annual VCS_total of 160.71Tg C·yr⁻¹. The VCS_rate was highest in forest (0.75 Mg C·ha⁻¹·yr⁻¹), followed by shrubland and grassland (0.18 and 0.03 Mg C·ha⁻¹·yr⁻¹). The VCS_rate increased at a rate of 15.18%, particularly in the warm temperate zone (WT) and the north subtropical zone (NS), increased by 83.24% and 38.86%, respectively. The ecological restoration programs (ERPs) contributed to 72.29% of the total increase in the national VCS_total during 20 years. Especially, the shelterbelt program for upper and middle reaches of Yangtze River (SPYT) accounted for 40.69%. Overall, ERPs have the best carbon sequestration effect in the NS and WT, with 52.46 and 48.36 Mg C·ha⁻¹·yr⁻¹ higher than outside ERSs area. Conversely, the VCS effect of ERPs was not significant in the plateau zone, so planting behavior in vulnerable regions should be taken with caution. It is imperative to identify appropriate ecological stewardship measures for future climatic conditions, informed by specific temporal and geographical contexts, to enhance carbon sequestration efficiency. These findings are crucial for guiding ecological protection and restoration strategies and carbon neutrality efforts in China and globally.