Mineral weathering is a critical geological process that regulates global climate. The weathering of carbonate, due to its rapid kinetic characteristics, can efficiently capture atmospheric CO₂ over geological timescales. In recent years, carbonate weathering has been recognized for its significant potential in enhancing atmospheric CO₂ capture through human regulation. In the past decades, widespread ecological restoration projects across many regions have generated substantial ecological benefits, notably through vegetation greening and increased atmospheric CO₂ capture. Carbonate weathering is closely related to changes in vegetation cover. Recently, some global case studies suggest that vegetation greening induced by ecological restoration projects may influence carbonate weathering intensity. However, systematic research has been lacking to elucidate the mechanisms by which vegetation greening affects carbonate weathering and to evaluate its impact on the atmospheric CO₂ capture benefits of global carbonate weathering.

To clarify how carbonate weathering and its Weathering Sink for atmospheric CO₂ (WS_atmCO2) respond to vegetation greening, a research team led by Prof. Zaihua Liu from the Institute of Geochemistry, Chinese Academy of Sciences, in collaboration with Southwest University and the Karlsruhe Institute of Technology in Germany, conducted a quantitative assessment of weathering intensity (carbonate) and carbon sink fluxes over the past 40 years in southwestern China and global carbonate regions. The study revealed a significant positive correlation between carbonate weathering intensity (indicated by [HCO₃⁻]) and vegetation greenness. Specifically, from 1982 to 2018, driven by vegetation greening induced by ecological restoration projects implemented, [HCO₃⁻] concentrations and carbon sink fluxes from carbonate weathering in southwestern China increased by 5.8% and 6.1%, respectively. Globally, vegetation greening led to a 2.4% rise in [HCO₃⁻], demonstrating that carbonate weathering intensity and carbon sink fluxes have significantly increased under the influence of vegetation greening in recent decades. The team also analyzed [HCO₃⁻] data from carbonate-controlled springs across global climate zones alongside local land surface vegetation greenness, finding that greener regions exhibited higher [HCO₃⁻] levels in spring water—further confirming vegetation’s dominant role in regulating carbonate weathering.

Figure.1 Key environmental parameters and [HCO₃^-] trends under different scenarios and its WS_atmCO2 in the carbonate region of southwest China over the past 40 years.

To further unveil the mechanisms behind vegetation greening’s control over carbonate weathering, the team employed different biogeochemical models and a field simulation test site to evaluate weathering intensity under various global change scenarios. Results showed that if vegetation greening were excluded and only climate warming considered, [HCO₃⁻] from carbonate weathering in southwestern China and globally would decline by 1.3%. Conversely, excluding warming effects revealed that vegetation greening enhanced [HCO₃⁻] by 7.3% in southwestern China and 3.7% globally. Moreover, global vegetation restoration could amplify carbonate weathering ([HCO₃⁻]) by up to 43.8%. However, ongoing global warming is expected to negatively impact carbonate weathering intensity, though continued vegetation greening and productivity improvements may reverse this trend. These findings not only highlight the role of vegetation function in enhancing carbonate weathering over recent decades but also detect it as a key factor in reversing the adverse effects of global warming on carbonate weathering and WS_atmCO2. In conclusion, this study demonstrates that future ecological restoration and vegetation greening in carbonate regions could serve as a potential strategy for regulating WS_atmCO2, offering significant scientific and practical implications.

Figure. 2 Field-scale simulated catchment located at the Puding Karst Ecosystem Research Station and its long-term [HCO₃^-] trend under vegetation greening scenario

The findings were recently published in Nature Communications, with Prof. Zaihua Liu as the corresponding author and Prof. Sibo Zeng from Southwest University as the first author. Collaborating institutions included Southwest University and the Karlsruhe Institute of Technology. The research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB40020000), the National Natural Science Foundation of China (No. 41942004, 42130501, 42141008).

Contact：

LIU Zaihua

State Key Laboratory of Environmental Geochemistry 

Institute of Geochemistry, the Chinese Academy of Sciences

Email: liuzaihua@mail.gyig.ac.cn

(By Prof. LIU Zaihua’ s group)