Anthropogenic activities have accelerated the restoration of carbon sequestration services in the upper Yellow River

Carbon sequestration services stemming from ecosystems facilitate the absorption of CO₂ and mitigation of greenhouse effects. Thus, investigating the spatiotemporal changes of carbon sequestration services and their response patterns to human activities is essential in relation to achieving the strategic carbon peak and carbon neutrality (“double carbon”) goal in a region. In this study, the spatiotemporal carbon sequestration patterns in the upper reaches of the Yellow River from 1985 to 2020 were assessed based on measured sample points and spatial modeling combined with multi-source remote sensing data. Specifically, the impacts of human activities on the carbon sequestration services in the area were quantitatively analyzed. The results showed that, for the past 35 years, carbon sequestration in the upper reaches of the Yellow River ranged from 80.09 Tg to 98.48 Tg, with lower levels in the northeast and southwest, and higher ones in the northwest and southeast. From 1985 to 1998, carbon sequestration in the upper reaches of the Yellow River was mainly affected by the natural climate and showed a fluctuating upward trend. From 1998 to 2001, carbon sequestration declined sharply due to the influence of human activities and the natural climate, whereas it showed a significant increasing trend from 2001 to 2020, affected by the combined effects of ecological engineering and climate change. In 1998–2001, the degree of human influence was −5.92% to approximately −11.68%, and from 2001 to 2020, it was approximately 2.32% to 6.78%. This study shows that while human social development can negatively affect the carbon sequestration services of ecosystems, ecological engineering can accelerate its recovery, recovery trends and recovery endpoints are constrained by natural factors.