The future of water on Earth's 'Third Pole'
The “third pole”, made up of the Himalaya, Karakoram and Hindu Kush mountain ranges, provides water to around a billion people or simply a seventh of the world's population.
The “third pole”, made up of the Himalaya, Karakoram and Hindu Kush mountain ranges, provides water to around a billion people or simply a seventh of the world's population. Climate change is melting the glaciers and scientists foresee a looming water crisis in this region.
Here are few imminent changes expected in the region:
Warmer air is changing the pattern of the monsoon, is changing the water cycle. Crops that we grow are based on the seasons and water cycle. This is also changing snowfall and rainfall, and how and when the snowpack and glaciers melt. The melting is increasing the risk of local hazards such as landslides and flooding.
Debris dam "failures" on glacial lakes, that is, dams failure will blocks access to mountain villages and pastures. It can also damage roads and bridges. These failures are also caused because of fast melting of the ice.
Flash flood in glacial lakes: Lower Barun in Nepal is one of the largest glacial lakes formed because of melting snow. The lake is 673 feet (205 metres) deep with a volume of almost 30 billion gallons (112 million cubic metres), or about 45,000 Olympic-sized swimming pools full.
These glacial lakes can cause flash floods. As it gets filled with water, a normal earthquake or rockfall can increase the weight of water causing the dam to collapse.
Scientists say that glacial lakes were unknown as around 50-60 years ago. Now, the glaciers are shrinking and retreating. These melting glaciers have created the lakes that are growing and proliferating.
The NASA team HiMAT mapped lakes larger than about 1,100 feet (330 metres) in diameter for three different time periods – about 1985, 2001 and 2015. The observations show that lakes have evolved.
The increase in size and number of lakes is a threat to the local population and infrastructure. Scientists are using satellite data to predict the areas with most susceptible to landslides.
Rate of melting of ice also depends on dusts. Never came to mind, right! Yes, white snow reflects 90 per cent of incoming solar radiation back into the atmosphere. But, dust, soot and pollution that settle on the frozen surfaces absorb more heat and melt the snow faster.
When snow is blanketed by darker-coloured particles of soot or dust, the coating absorbs more heat and the snow melts faster.
Soot was the reason of ending of Little Ice Age in Europe. So, scientists are expecting that the increase in soot deposit on the Asian mountains might have similar effect.
Glaciers are expected to be 30-70 per cent smaller in volume by 2100. This assessment is based on the facts gathered by scientists from satellites.
People in the region are already modifying the land usage practices in response to the changing water supply. The ecology of the region is also transforming. The change in water supply is going to influence food and water security in India, Pakistan, China and other nations that are related to it.