Impact of Humans on the Flux of Terrestrial Sediment to the Global Coastal Ocean
James P. M. Syvitski,1*
Charles J. Vörösmarty,2
Albert J. Kettner,1,3
Pamela Green2
Here we provide global estimates of the seasonal flux of sediment, on a river-by-river basis, under modern and prehuman conditions. Humans have simultaneously increased the sediment transport by global rivers through soil erosion (by 2.3 ± 0.6 billion metric tons per year), yet reduced the flux of sediment reaching the world's coasts (by 1.4 ± 0.3 billion metric tons per year) because of retention within reservoirs. Over 100 billion metric tons of sediment and 1 to 3 billion metric tons of carbon are now sequestered in reservoirs constructed largely within the past 50 years. African and Asian rivers carry a greatly reduced sediment load; Indonesian rivers deliver much more sediment to coastal areas.
1 Environmental Computation and Imaging Facility, Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, CO 80309-0450, USA.
2 Water Systems Analysis Group, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA.
3 Applied Earth Sciences, Delft University of Technology, Delft, Netherlands.
* To whom correspondence should be addressed. E-mail: james.syvitski{at}colorado.edu
