Rivers worldwide are steadily losing dissolved oxygen, with climate change identified as the primary driver in a comprehensive new study. Nearly 80 percent of analyzed river systems have shown declines over four decades, hitting tropical regions hardest.
Researchers examined observations from 21,439 river reaches collected between 1985 and 2023. They determined that oxygen levels dropped at an average rate of 0.045 milligrams per liter per decade, with 78.8 percent of rivers affected by deoxygenation. The study was led by Prof. Kun Shi of the Nanjing Institute of Geography and Limnology at the Chinese Academy of Sciences, with Dr. Qi Guan as first author and input from Tongji University.