The river's function is affected by how much it transports and deposits.
Sand, silt and clay play a critical role in the ecology of the river. buffering the rise in sea levels from climate change by delivering sand todeltas and coastlines is important for human life.
Humans have caused a lot of changes to river transport in the past 40 years.
The researchers looked at changes in how much silt was carried to the ocean from 1984 to 2020 using satellite images.
According to lead author Evan Dethier, humans have been able to change the world's biggest rivers at unprecedented rates. Natural processes in the Watershed such as how much rain there is or whether there is vegetation dictate the amount of river carry. The effects of climate change are being overshadowed by human activity.
The findings show that dam building in the 20th century reduced the global delivery of water from rivers to the oceans. South America, Africa and Oceania have seen an increase iniment transport due to land use change.
In the past several centuries, dam building has been the main agent of change in the North. The global expansion of large dams has been one of the reasons for the research.
The floodplains, sandbars, estuaries and Deltas are created by the river. Once a dam is in place, the supply of soil and water is usually shut off.
Future changes for the South could be predicted by the results in the north. The Amazon River is the most polluted river in the world and there are more than 300 dams planned for it.
"Rivers are a good indicator of what we are doing to the surface of the Earth," says co-author Carl Renshaw. There's a soil loss crisis in the U.S., but we don't see it in the export record because it's all getting stuck behind these dams.
The researchers hope that they can be used to inform planning decisions and environmental management policies in the future.
More information: Evan N. Dethier et al, Rapid changes to global river suspended sediment flux by humans, Science (2022). DOI: 10.1126/science.abn7980 Journal information: Science
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