Climate Change Heating Up Indian Rivers

According to a recently published study, climate change may turn India’s rivers into hostile environments for aquatic life by 2070-2100.

• Key Highlights: The study covered seven Indian basins: Ganga, Narmada, Cauvery, Sabarmati, Tungabhadra, Musi and Godavari.
• Methodology: The team used computer-modelling to predict river water temperatures and dissolved oxygen levels across the seven basins.
• With the help of Artificial Intelligence (AI), using data on air temperatures, the team predicted the historical, present and future river water temperatures for each of the seven basins. This was then converted into dissolved oxygen levels.
• River Water Temperatures: River water temperatures may increase during the period (2070-2100) and dissolved oxygen levels may decrease.
• Currently, the average river water temperature varies between basins. For example, it is 30.34°C in Cauvery and 27.97°C in Musi.
• Under a high-emissions scenario, river water temperatures are expected to climb 7 degrees Celsius in summer, reaching close to 35°C by 2070-2100. An increase in air temperature aggravates river water temperatures.
• Dissolved Oxygen Levels: Dissolved oxygen levels can drop to 7.3 milligrams / litre of water from 7.9 milligrams / litre at present under a high emissions scenario.

Impact: Aquatic organisms use dissolved oxygen to breathe. But oxygen becomes less soluble in warmer and polluted waters.

• The riverine species cannot survive for long when the level of dissolved oxygen drops below 4-5 mg / l of water. This results in loss of aquatic biodiversity.