Shimla: The recent exploration by the Geo-scientists on the Himalayan Mountain ranges has shone a new light on the origin and dying of lakes. Leh was a city of lakes and the Pangong lake originated from a river while 55,000 glaciers of HKHK store more freshwater than the North and South Poles.
The papers presented by the concerned experts said: ”Leh was a city of Lakes and today’s Pangong lake was a river and tributary of Shyok river 1,000 years ago. This is the conclusion of the investigations carried out by the team of geologists and environmental students of Ladakh Science Foundation headed by Ritesh Arya.”
What if one said the lakes which were center of attraction in the past are today nowhere to be found and are extinct, including the famous paleolake at DBO (Daulat Beg Oldi) — Shey Spituk and Lamayuru which is also known as the moon land on earth and the present lakes of Pangong and Tsomoriri — were rivers and tributaries of Shyok and Satluj in the past and are today lakes.
This has been revealed in an international conference on “EARTH AND ENVIRONMENT IN ANTHROPOCENE” (ICEEA-2021) by the team of geoscientists from Ladakh Science Foundation working under the guidance of Arya.
Arya, spent more than two decades studying the impact of climate change on the water resources on Ladakh, especially the groundwater based on the borewells drilled.
The study found dying lakes in the Leh and Ladakh and present days glacial bodies and lakes revealing interesting facts.
Replying to a query as to why today’s Pangong lake contains salty water, Arya said it has nothing to do with the Eurasia Sea water becoming salty. After erosion of minerals in water with this lake and decreasing water level with the time in the Pangong and other Himalayan lakes turned salty, he said.
These fresh water lakes were lifeline for the traders traveling with their camels and horses on the old Silk Route. The dynamics of these lakes changed due to climatic conditions and the end of these lakes due to unprecedented climate change ultimately led to the end of the Trade on the Silk route.
Replying to another query as to how climate change and Global warming have impacted the Lakes of Ladakh, he said the recent paper has revealed that lakes in the high altitude of cold mountain deserts of Ladakh have been center of attraction for everyone since time immemorial.
In ancient times these lakes were the lifeline for the travellers moving along the ”old Silk Route whereas the Pangong lake famous after the shooting of the ‘3- IDIOTS’ and now escalated tension with China has been the centre of attraction, as well even then in medieval ages.
He said that in the paper Climate change and Global warming: Impact on Lakes of Ladakh by Ritesh Arya, Mohd Ilyas, Kunzang Dolma and Tajalli Mohiuddin explain how the two climatic factors are impacting Glaciers in the Himalayas.
Arya said that glaciers in the Himalayas are either extinct or on the verge of extinction; this happened much before industrialization.
According to World Bank report BOOK Glaciers of the Himalayas: Climate Change, Black Carbon, and Regional Resilience suggest that ”there are 55,000 glaciers in the Himalaya, Karakoram, and Hindu Kush (HKHK) mountain ranges that store more freshwater than any region outside of the North and South Poles.
Their ice reserves feed into three major river basins in South Asia — the Indus, Ganges, and Brahmaputra — that are home to 750 million people.
Melting glaciers and the loss of seasonal snow pose significant risks to the stability of water resources in South Asia.
In the past during the Ice age, the glaciers were massive and evidence of the Indus Glacier extending from Mansoarvar in the Himalayas to the Arabian sea were found in the borewells drilled in 2013. Similarly evidence of glacial recedes of more than 74 km and 24 km respectively, have been found at Siachen and Khardungla 2013 by Arya.
The present paper highlights the impact of climate change, especially global warming, on the lakes located in the high altitude cold mountain deserts of Ladakh Himalayas. Pangong and Tsomoriri lakes of today in the Changthang region of Ladakh were once perennial tributaries of Shyok and Satluj respectively in the past.
Since the end of the Last Ice age around 11,700 years back, the impact of global warming led to the melting of the glaciers. Receding glacial melt decreased discharge in the tributaries and the natural blockageat Lukung resulted in the conversion of perennial tributaries leading to the formation of Pangong lake.
The rates of the recession of glaciers in those times were very high as compared to the present times. Sicahen glacier had receded more than 74 Kms and Khardungla more than 24 km and is today confined to the peaks. This is evident from the small lakes found at the South Pole today.
Similar deposits in Shey indicate a paleolake formation in the past which was fed by the receding Stakmo glacier. But the lake dried due to lack of water from Stakmo catchment area.
In Spituk lake dried due to paleo-flooding event from Indus and cloud burst at Spituk, the seismic activity could also have triggered the breach of the lake wall leading to its rupture and final death of the once massive lake.
In Lamayuru, also known as moonland on earth, glacial lake was formed due to the blocking of glaciers by mountains. Over time this led to disintegration of shells into clay during cooling times and a lake was formed.
Later the lake breached due to paleflooding activity induced due to global warming leading to increased discharge creating a hydrostratigraphic disequilibrium. Tangsay was no exception and the lake was formed due to blockage of glaciers from Changla atTangsay. Later the temporary wall made of debris not able to withstand the hydrostatic pressure breached at Durbuk leading to glacial lake outburst.
Glacial evidence is very well preserved in the valley. Temporary lakes were also formed due to blockage of Indus at Phyang and Nimmu but their life was very limited as the flow of Indus and lake created a hydrostatic pressure which breached the wall leading to instantaneous death of those lakes.
The phenomenon similar to the Leh floods of 2010 when river Indus was temporarily blocked by floods at Choglamsar and Nimmo for a few minutes.
The paper also analyses and establishes the role of Chortens or Stupas and Manay walls constructed by man in response to mitigate and manage natural disasters caused due to glacial melt 1,000 years ago when the floods from glacial melt dominated the scenario.
Today their actual role has been forgotten and is confined to religious rituals by the buddhists.
Need of the hour is to protect and preserve these paleo glacial lake deposits so that the entire record of climate change is preserved for the scientists to study the changes the climate has undergone since the last warming times in the high altitude region of Ladakh Himalaya, Arya said. By Mohan Lal Verma
