Researchers from Utrecht University in the Netherlands, Woods Hole Oceanographic Institution (WHOI), and colleagues found that delta areas worldwide have actually gained land in the past 30 years, despite river damming. However, recent land gains are unlikely to last throughout the 21st century due to expected, accelerated sea level rise.
Researchers from Utrecht University in the Netherlands, Woods Hole Oceanographic Institution (WHOI), and colleagues found that delta areas worldwide have actually gained land in the past 30 years, despite river damming. However, recent land gains are unlikely to last throughout the 21st century due to expected, accelerated sea level rise. The researchers published their findings in the journal Nature.
River deltas rank among the most economically and ecologically valuable environments on Earth. People living on deltas are increasingly vulnerable to sea-level rise and coastal hazards such as major storms, extremely high tides, and tsunamis. Many deltas experience a decline in sediment supply due to upstream damming, making them even more vulnerable. However, the new study found that long-term, large-scale, upstream deforestation has resulted in soil erosion that increased the amount of sediment transported to many deltas.
“A large driver for these gains turned out to be human action,” says lead author Jaap Nienhuis, a geoscientist at Utrecht University and a graduate of the MIT-WHOI Joint Program. “Twenty five percent of delta growth can be attributed to upstream deforestation, which results in soil erosion and increased sediment delivery to the coast. Human action such as damming causes sediment starvation and increased importance of wave- and tide-driven transport, which can also change delta shape.”
Read more at Woods Hole Oceanographic Institution
Image: Deltas along the north shore of Java, Indonesia, which have expanded in recent years following large-scale deforestation in the drainage basins. (Image courtesy of NASA/Landsat 2020)
