Dangerous torrents of water and ice that could decimate several coastal cities are a worrying threat hanging over the Yellow River, China's second-largest waterway.
Researchers have found that global warming is leading to the formation of massive blocks of ice that could break apart at any moment, thereby increasing the flood risk in a geographical region already highly prone to flooding.
Located in China, the Yellow River is over 5,400km long and is one of the world's largest rivers.
Considered the cradle of Chinese civilisation, it is also known as "China's Sorrow” due to its impressive and deadly floods, which have been ravaging the region for over two centuries.
And the risk of flooding could increase in the coming decades due to a specific phenomenon exacerbated by climate change, according to research conducted by scientists from the University of Bern (Switzerland) and the Chinese Academy of Sciences (Beijing, China), and published in the journal Science Advances.
Based on data and statistical models compiled over the past 160 years, the study authors found that ice jams (accumulations of natural materials carried by water) are likely to increase the risk of flooding in the Yellow River.
More specifically, these ice jams are related to blocks of ice formed near the river's source (the Tibetan plateau) that break up when temperatures rise in early spring, but which have gradually moved downstream over time due to global warming.
The water then migrates to the colder currents of the river and freezes, creating an ice "traffic jam” that threatens to collapse, releasing torrents of ice and water."
Our findings show that ice-jam floods are strongly influenced by large-scale atmospheric teleconnections, including the Arctic Oscillation, Siberian High and Ural Blocking, which regulate regional thermal contrasts and cold-air intrusions," the researchers write.
Although these potential floods seem to be more likely to occur in coastal areas, they could have devastating consequences for nearby ecosystems and infrastructure, according to the study authors.
They particularly emphasise the increased risk of flooding for several coastal cities in China (notably Binzhou, Dongying and Shandong) and the resulting water shortages.
"Our study bridges historical and future perspectives, emphasising the need for adaptive flood management as climate change shifts hydrological risks worldwide," the scientists conclude. – AFP Relaxnews
