The dynamic trajectory of carbon dioxide removal from terrestrial ecosystem restoration: A critical review

Anthropogenic climate change poses a significant threat to global ecosystems, necessitating nature-based solutions to achieve net-zero emissions and mitigate climate change. Restoration of degraded ecosystems is critical for terrestrial carbon dioxide removal (TCDR), in addition to preserving biodiversity and reducing emissions of carbon and other greenhouse gases. However, the quantitative estimation of TCDR from ecosystem restoration remains uncertain, especially for future projections, because most of these estimates are based on static conditions and do not consider the dynamic trajectories of restoration. Therefore, our paper presents a comprehensive review of current TCDR research and the dynamic trajectory of restoration for TCDR. First, we outline four main theoretical trajectories of ecosystem carbon changes during restoration, emphasizing that the primary goal of TCDR through ecosystem restoration is to increase net primary productivity and extend the residence time of ecosystem carbon. Second, we showcase representative TCDR trajectories in different ecosystems through case studies, emphasizing the importance of understanding the long-term dynamic trajectory of ecological restoration by considering variations among ecosystems, restoration methods, and plant biodiversity. Third, we comprehensively reviewed the potentials and the associated uncertainties in TCDR, including different restoration actions, biological regulations, and environmental changes. To accurately predict TCDR from ecosystem restoration, accounting for these factors and using appropriate trajectory equations in models is essential. In conclusion, our work advocates for a future research focus on quantifying TCDR by considering the dynamic trajectory of ecosystem restoration to improve the accuracy of TCDR assessment and prediction, thereby significantly benefiting climate change mitigation efforts.