The seventh-longest river in the world, the Yellow River, irrigates 15 percent of China’s farmland, such a broad dissemination of water that it has a measurable effect on temperature, says a team of scientists. In a paper published in Atmospheric and Oceanic Science Letters, they said that when irrigation is in use, air temperatures are lower.
“The agricultural irrigation affects the regional climate mainly through changing the surface water process,” said the lead author, Chen Liang, an assistant researcher at the Institute of Atmospheric Physics. Chen said other researchers have looked into the effects of changes in soil moisture, “but the role of irrigation has not been sufficiently depicted in those studies.”
In a release, the Chinese Academy of Sciences said water usage in the Yellow River basin in northern China “is challenging due to drought and increasing water consumption.” An estimated 400 million people live in the basin. At times, the river runs dry before reaching the Yellow Sea because of competition for water between farms, industry and cities.