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Global warming and vanishing glaciers: Uttarakhand disaster revies
Read more on - Polity | Economy | Schemes | S&T | Environment
- A scientific warning: The February disaster in Uttarakhand's Chamoli has again turned the spotlight on climate change and its impact on ecology. On February 7, a portion of Nanda Devi glacier broke off, leading to severe floods which washed away villages and damaged power plants. Hundred of people were missing, and many of them were feared dead. Though the actual cause of the glacier burst is being probed, scientists for long had warned that glaciers are disappearing from the Earth and global warming, especially in the last three decades, is a major reason behind it. As the world is getting hotter, ice caps on mountains are melting rapidly.
- The future: Experts have warned that at this rate, the Himalayas might lose one-third of its glaciers by the end of this century. This is bound to be catastrophic for two billion people residing in and around the mountain range in India and neighbouring countries. To be sure, there have been contrary voices too, that have claimed this is all exaggerated.
- Recent warnings: In July 2020, experts had warned about melting of glaciers in the Nanda Devi region. A study by IIT Kanpur and Dehradun-based Wadia Institute of Himalayan Geology shows nearly 26 square kilometres of the glaciated area of Nanda Devi region was lost in 37 years. The study revealed that the glaciers of the valley lost 26 km² (10%) of the glaciated area between 1980 and 2017. The total glacierized area in 2017 is 217 km², which is 26% of the total area. However, during the same periods (1980-2017) the Equilibrium Line Altitude (ELA) of the glaciers fluctuated between 5200 and 5700 m asl (metres above sea level). The present study suggests that the glaciers in the region have responded to deprived precipitation conditions since 1980.
- A Himalaya of lakes: As the Himalayan glaciers rapidly melt, where will all the water—more than a quadrillion gallons of it, go? The answer is that the Himalaya, long defined by its glaciers, is rapidly becoming a mountain range defined by lakes. Studies found that from 1990 to 2010, more than 900 new glacier-fed lakes were formed across Asia’s high mountain ranges. To understand how these lakes form, think of a glacier as an ice bulldozer slowly plowing down the side of a mountain, scraping through the earth, and leaving a ridge of debris on either side as it pushes forward. These ridges are called moraines, and as glaciers melt and retreat, water fills the gouge that remains, and the moraines serve as natural dams. They start as a series of meltwater ponds and coalesce to form a single pond, then a larger lake. And year by year they get larger and larger, until you have a lake with millions of cubic meters of water. As the lake fills up, it can overspill the moraines holding it in place or, in the worst-case scenario, the moraines can give way. Scientists call such an event a glacial lake outburst flood, or GLOF. There’s also a Sherpa word for it: chhu-gyumha, a catastrophic flood.
- Worldwide impact: Climate change is driving temperatures up dramatically in India and the world. India has witnessed more than half degree Celsius rise in average temperature in the last 10 years, while global temperature reported anomalies of about one degree Celsius. Data shows almost all major cities are witnessing a rise in average temperature. The global mean temperature in 2020 is estimated to have been 1.27 °C (2.29 °F) above the average temperature of the late 19th century," Berekeley Earth, a climate research institute, said in its global report of 2020.
- Recent years: The last six years stand out in terms of temperature rise in 200 years. The rising temperature has put global ice caps and glaciers at higher risk. However, scientists are divided on whether global warming is responsible for such disaster as witnessed in Uttarakhand. Preliminary investigations show that the event in Uttarakhand is caused by a landslide. It would require more research on this to conclude if it was a man-made disaster. A similar event had happened in the region around 2016 (probably with lesser impact) which indicates that this is a very sensitive region.
- Causality debated: Even though the causality of the event is debated, the effects of the disaster are because of human interventions. The deaths would not have happened if we avoid building such massive infrastructure projects in sensitive areas. But there are tends of hydropower projects under construction across the region. Some experts also say that there is a chance of formation of a glacial lake, which got ruptured somehow and a flash flood occurred.
- Details of rivers: The Alaknanda river is a Himalayan river in Uttarakhand, one of the two headstreams of River Ganga. The other is the Bhagirathi. River Alaknanda is also called as the source stream of the Ganges because of its greater length and discharge. But in Hindu mythology and culture, Bhagirathi is called as the source stream of Ganga. There are five main tributaries of Alaknanda in order namely the River Dhauliganga, River Nandakini, River Pindar, River Mandakini and River Bhagirathi. All of them rise in the northern mountainous regions of Uttarakhand. It is one of the best river for river rafting in the world because of its high rafting grade. At Vishnuprayag, Dhauliganga River meets Alaknanda river. At Nandaprayag, Nandakini River meets Alaknanda. At Karnaprayag, Pindar River meets Alaknanda. At Rudraprayag, Mandakini River meets Alaknanda. At Devprayag, Bhagirathi River meets alaknanda and it officially becomes River Ganges. Dhauliganga is among the six source streams of the River Ganges river. The river meets the river Alaknanda at Vishnuprayag in Joshimath.
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