Flow Chart Unclear for Glacial Rivers

A new study examining river basins in the Asia region suggests that amounts of water supplied to the area by glaciers and rainfall in the Himalayas will increase in the coming decades.

At first reading, that looks like good news, as an estimated 1.3 billion people in Pakistan, India, Bangladesh, Nepal, China and elsewhere are dependent for their water supplies on rivers fed by glaciers and snowmelt.

But the less welcome news is that scientists are unsure what will happen after 2050 if the rate at which glaciers melt continues to increase as a result of climate change.

Scientists say rising temperatures and more intense rainfall patterns in the higher Himalayas are causing the retreat of the majority of glaciers in the region.

They say glacier melt is also being caused by black carbon – particulate matter that, in South Asia, comes mainly from cooking fires, the burning of waste, plus coal burning and diesel exhausts.  The black carbon, or soot, falls on the glaciers, reducing reflectivity and increasing heat build-up.

This latest study of glacier melt and water flows, appearing in the journal Nature Climate Change, was carried out by scientists at Future Water, a Netherlands-based research group, Utrecht University, and the Nepal-based International Centre for Integrated Mountain Development.

The study says the long-term outlook is particularly uncertain for the upper Indus basin. While glacier melt contributes only 11.5% of the total runoff in the upper basin of the Ganges river, it contributes more than 40% of total water runoff in the upper Indus basin.

The Indus river, which flows for nearly 2,000 miles from high up in the Hindu Kush-Karakoram Himalaya mountain range down to the Arabian Sea, is vital to life in Pakistan, providing water for 90% of the country’s agricultural crops.  Hydro plants along the Indus also supply about half the country’s electricity.

Flow Chart Unclear for Glacial Rivers