Accelerated soil erosion has become a pervasive feature on landscapes around the world and is recognized to have substantial implications for land productivity, downstream water quality, and biogeochemical cycles. However, the scarcity of global syntheses that consider long-term processes has limited our understanding of the timing, the amplitude, and the extent of soil erosion over millennial time scales. As such, we lack the ability to make predictions about the responses of soil erosion to long-term climate and land cover changes. Here, we reconstruct sedimentation rates for 632 lakes based on chronologies constrained by 3,980 calibrated 14C ages to assess the relative changes in lake-watershed erosion rates over the last 12,000 y. Estimated soil erosion dynamics were then complemented with land cover reconstructions inferred from 43,669 pollen samples and with climate time series from the Max Planck Institute Earth System Model. Our results show that a significant portion of the Earth surface shifted to human-driven soil erosion rate already 4,000 y ago. In particular, inferred soil erosion rates increased in 35% of the watersheds, and most of these sites showed a decrease in the proportion of arboreal pollen, which would be expected with land clearance. Further analysis revealed that land cover change was the main driver of inferred soil erosion in 70% of all studied watersheds. This study suggests that soil erosion has been altering terrestrial and aquatic ecosystems for millennia, leading to carbon (C) losses that could have ultimately induced feed-backs on the climate system.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Nov 12 2019|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. The work of the data contributors and the pollen database community is gratefully acknowledged. This study was supported by the AXA Research Fund (to J.-P.J.), the Canada Research Chairs Program and NSERC (P.F. and I.G.-E.), and is a contribution for the Varve Working Group and the working group on “Global Soil and Sediment transfer in the Anthropocene,” within the International Future Earth core project Past Global Changes (PAGES), from which the original idea emerged.
© 2019 National Academy of Sciences. All rights reserved.
Copyright 2020 Elsevier B.V., All rights reserved.
- C ages
- Global soil erosion
- Lake records
- Varved sediments
Continental Scientific Drilling Facility tags