The Himalayan mountain range carries religious, economic, ecological and strategic significance on many levels. In fact, the most visited places of pilgrimage in India are located in the Himalayas.
The Himalayan mountain range extends in a 2,410 km curve across South Asia. The Himalayas separate the plains of the Indian subcontinent from the Tibetan Plateau. The Himalayas include over fifty mountains exceeding 7,200 m (23,600 ft) in elevation, including ten of the fourteen 8,000-metre peaks, including the Mount Everest. India has the largest share of the mighty Himalayas.
The Himalayas are inhabited by 52.7 million people and are spread across five countries: Bhutan, China, India, Nepal and Pakistan. There are almost 22,000km² of glacier ice in the Himalayas.
Some of the world’s major rivers like the Indus, the Ganges and the Tsangpo-Brahmaputra rise in the Himalayas, and their combined drainage basin is home to roughly 800 million people. The Himalayas have a profound effect on the climate of the region, helping to keep the monsoon by rains on the Indian plains and limiting rainfall on the Tibetan plateau.
The Himalayas have deeply shaped different cultures of the Indian subcontinent; many Himalayan peaks are sacred in Hinduism, Buddhism, and Jainism.
The Himalayan mountain range and Tibetan plateau have formed as a result of the collision between the Indian Plate and Eurasian Plate, which began 50 million years ago and continues today. Some 225 million years ago (Ma), India was a large island situated off the Australian coast and separated from Asia by the Tethys Ocean.
Recent researches have shown that most of the glaciers in the Himalaya are shrinking, mostly because of increasing global temperature. The number of cold nights reduced by one night per decade and the number of cold days reduced by 0.5 days per decade, while the number of warm nights increased by 1.7 nights per decade and the number of warm days increased by 1.2 days per decade.
According to a recent study, the black carbon concentration that contributes to faster melting of glaciers has almost doubled on the Gangotri Glacier. Developmental activities, pollution from local, regional and global sources accumulate over the Himalayan region and increase the concentration of black carbon.
These changes will continue and pose more acute challenges to adaptation. If the pivotal 1.5 °C target would be reached, the Himalayan glaciers would expectedly lose one-third of their surfaces. In future, the sustainability of river flow in south-east Asia will be at risk.
The consequences of climate change are being witnessed in the Himalayan glaciers and glacial lakes. The Himalayan cryosphere, the source of major river systems and lifeline in Asia, is shrinking and resulting in to increase in the size and number of glacial lakes. The Himalayan glaciers are retreating at rates ranging from 10 to 60 metres per year, and many small glaciers (< 0.2 sq km) have already disappeared.
Vertical shifting of glaciers has been recorded during the last fifty years. With the result of melting glaciers, the lakes are growing. A remarkable example is Lake Imja Tsho in the Everest region, while this lake was a non-existent in 1960, now it covers more than one sq km in area. Similarly, in the Pho Chu basin of the Bhutan Himalaya, the change in the size of some glacial lakes has been observed as high as 800 per cent over the past 40 years.
At present, several supraglacial ponds on the Thorthormi glacier are growing rapidly and consequently merging to form a larger lake. These lakes pose a threat of ‘glacial lake outburst flood‘ (GLOF). GLOFs are often catastrophic on life and property of the mountain people living downstream, besides damages to agricultural land and forests. Most of these lakes had formed only in the second half of the twentieth century due to global warming.
Mountain lakes are just like ‘mountain tsunamis’. Catastrophic outbursts of glacial lakes result in widespread damage to people and villages, washed away bridges and roads, and fill in the river water with debris and large logs.
Kedarnath disaster of June 2013 is an example of a ‘catastrophic mountain tsunamis’. On 16th and 17th June 2013, heavy rains, along with moraine-dammed Chorabari Lake burst, caused flooding of Saraswati and Mandakini Rivers in Rudraprayag district of Uttarakhand and damaged the banks of River Mandakini for 18 km between Kedarnath and Sonprayag and completely washed away Gaurikund, Rambara and Kedarnath towns.
The Chorabari Lake also known as Gandhi Sarovar Lake is snowmelt and rain-fed lake located about 2 km upstream of Kedarnath town; it is approximately 400 mt long, 200 mt wide having a depth of 15–20 mt. The bursting of the lake led to its complete draining within 5–10 mins and resulted in catastrophe.
Studies on selected glaciers of Indian Himalaya indicate that most of the glaciers are retreating because of increasing global warming. Of these, the Siachen, Pindari, Gangotri, Milam, Dokriani Bamako, Gara, Gor Garang, Shaune Garang, Nagpo Tokyo, Bara Shigri, Chhota Shigri, Miyar, Hamtah, Nagpo Tokpo, Triloknath, Sona, Janapa, Jorya Garang, Naradu Garang, Bilare Bange, Karu Garang and Baspa Bamako, Parbati and Shaune Garang glaciers are retreating at faster speeds.
Global warming has affected snow-glacier melt and runoff pattern in the Himalaya. One of the best examples of glacier retreat is Gangotri glacier, where the position of Gangotri Glacier snout has been shifted about 2km upward from 1780 to 2001 and is in a continuous process. Gangotri Glacier is 29 kilometres long, two to six kilometres wide and the longest glacier in the Central Himalayas. It sweeps like a gigantic river through the heart of the mountains.
The mountains make up 24% of the world’s land area, are home to about 20% of the world’s population, provide 60–80% of the world’s freshwater and harbour 50% of the world’s biodiversity hotspots. The United Nations recognized the importance of mountain ecosystems, in chapter 13 of Agenda 21.
World nations should move towards achieving the targets of ‘Paris Agreement’ to save Himalayan biodiversity, human life, economy and ecology. Himalayan nations should cooperate in setting an early warning system. Our weather reporting and satellite images can alarm us before probable catastrophes in future. Sustainability should be maintained in Himalaya, during development activities. Development is essential, but not at the cost of sustainability, habitat loss and loss of human lives. Glaciers are our lifeline, and we must save them.