Overview
- A peer-reviewed analysis in Science Advances of satellite and climate data from 1985 to 2023 finds declining dissolved oxygen in nearly 80% of rivers worldwide.
- The team assessed more than 16,000 rivers using 3.4 million images and measured an average drop of 0.045 milligrams per liter each decade, about a 2.1% decline since 1985.
- Researchers attribute roughly 63% of the global decline to warming-driven loss of oxygen solubility, since warmer water holds less gas.
- Tropical rivers are the most vulnerable, with the Ganges losing oxygen about 20 times faster than the global average and the Amazon seeing more days with hypoxic conditions.
- Modeling projects around a 10% oxygen loss by 2100 in regions including India, South America, the Arctic, and the Eastern United States, after a further 4–5% decline within the next seven decades without strong climate and water management action.