Silicate weathering, a vital natural carbon sink process, has long been recognized for its role in consuming atmospheric CO2 and influencing global climate. However, the extent to which human activities have influenced silicate weathering fluxes and global carbon cycling in large river basins remains poorly understood.
To address this issue, a research team led by Prof. WAN Shiming from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) and their collaborators revealed enhanced silicate weathering carbon sink effect induced by human activities in Red River Basin since 1,500 years ago.
Their findings were published in Journal of Geophysical Research: Earth Surface on Oct. 24.
The researchers reconstructed the evolution of silicate weathering fluxes in the Red River Basin during the late Holocene using mineralogical and geochemical records from sediment core in the northwestern South China Sea. The results reveal that while climate change dominated silicate weathering intensity between 3,800 and 1,500 years ago, human activities became the primary driver after 1,500 years ago, significantly enhancing weathering-related carbon sequestration.
Their findings demonstrate that human activities, including mining, metallurgy, agricultural expansion, and warfare, have intensified silicate weathering in the Red River Basin since the Three Kingdoms-Northern and Southern Dynasties period. "This enhanced weathering has acted as a growing carbon sink, consuming approximately 150% more CO2 than under natural conditions, which accounts for approximately one-quarter of anthropogenic CO2 emissions during this period," said Prof. ZHAO Debo, co-corresponding author of the study.
These findings update the traditional "weathering-climate" feedback paradigm by showing that humans not only influence climate through greenhouse gas emissions but also enhance Earth's negative feedback mechanisms through artificially intensified weathering. "This has important implications for accurately understanding global carbon budgets and predicting future climate change," said Prof. WAN.
The research provides the first millennium-scale quantitative evidence of human enhancement of silicate weathering carbon sinks, suggesting that current Earth system models may underestimate the historical impact of human activities on carbon cycling. As human populations and resource utilization continue to grow, these findings underscore the need to incorporate anthropogenic weathering effects into global climate projections.
Schematic diagrams show the two stages of silicate weathering dominated by climate and human activities. (Image by IOCAS)
(Text by ZHAO Debo)
Media Contact:
ZHANG Yiyi
Institute of Oceanology
E-mail: zhangyiyi@qdio.ac.cn
(Editor: ZHANG Yiyi)