Thawing glaciers

The Hindu Kush-Himalayan (HKH) region is home to the loftiest mountain ranges on the planet spanning over 42 lakh km2. Often referred to as ‘The Third Pole’, it houses the largest volume of ice and snow outside the polar regions. These ‘Water Towers’ serve as the source of major river systems in Asia, providing water for more than a billion people, which is about 15 per cent of the world’s total population. Apart from being the origin of the majestic rivers, the ice, snow and permafrost help maintain the springs which are among the major sources of fresh water in the mountainous regions. These mountains, being significant physical barriers, also play an important role in the regional climate. The region is seeing rapid changes in its cryosphere due to the effects of climate change. The Lahaul and Spiti district in the North Western Himalayan encompasses a large expanse of glaciers, snow and permafrost. Nestled in the remote and rugged part of the Northwestern Himalayas, the district is witnessing significant changes in its water regime.

Considered a high-altitude cold desert, the district is also home to some of the largest glaciers in the entire region. With very little rainfall during the Indian summer monsoon months, Lahaul and Spiti rely heavily on glaciers and snowmelt for domestic and agricultural water needs.

The cryosphere comprising the frozen components of the earth’s surface, including glaciers, snow, and permafrost has a vital role in maintaining ecological balance and water security in the sensitive mountain regions of Lahaul and Spiti. However, in the face of a warming environment and shifting weather patterns, the cryosphere in Lahaul and Spiti is undergoing rapid changes, posing serious threats to the region's water resources and its inhabitants.

The reduced glacier mass has far-reaching implications for the people in the vicinity and downstream in terms of water availability affecting agriculture, hydropower generation, and overall water security. Undeniably the most visible and significant consequence of melting cryosphere for people in the region is the impact on water resources. In the district, melting cryosphere is a matter of serious concern as the local communities are the first to feel the brunt of the impacts of climate change.

Unfolding catastrophe

Several studies on glacier changes in the region suggest that the glaciers are retreating rapidly. The Bara Shigri glacier, the largest in the district, retreated substantially by about 2898 ±50 m between 1863 and 2014. The second largest glacier in the district, Miyar, retreated by 900 m between 1850 and 2019. The rate of recession has increased over the past decades. The Miyar glacier retreated at a rate of 4 m per year between 1850 and 1965, and the rate increased to 7.9 m per year. Between 2013 and 2019, the glacier retreated at an unprecedented rate of 11.5 m per year. This trend is similar to the recession pattern of the glaciers at the regional level. Rising temperatures and a decline in precipitation, especially snowfall dictated by climate change, are the major drivers behind the decline in the glacier cover. At the regional level, in the Northwestern Himalayas, the temperature has risen by 1.6° C on average in the last century. In addition to glacier retreat and decreasing snowfall, permafrost, another critical component of the cryosphere in the region, is also thawing. The thawing presents additional and significant threats to water security in the area.

Dwindling water resources

Water scarcity in the district is being widely reported. In some instances, the severity of the situation has forced people to relocate. Kumik village in the neighbouring Zanskar region, just north of Lahaul, faced such an acute water shortage due to lesser snowfall and shrinking glaciers that almost all the residents had to move to Lower Kumik village.

In Lahaul, the shrinking glaciers and less snowfall are also leading to the drying up of local water sources such as Kuhls (irrigation channels) and springs for irrigation and domestic use. Komic, a village situated at an altitude of 4,587 m asl, is grappling with a severe water crisis in the upper belt of Spiti Valley due to the drying up of streams, ponds and lakes fed by glaciers, seasonal snow and permafrost. In the Lahaul Valley, farmers of Tandi, a village near the Sangam (confluence) of the Chandra and Bhaga Rivers, lost almost 50 per cent of their crops in the summer of 2022 due to a shortage of water for irrigation. The local administration confirmed that the changing availability and pattern of snowfall in the region has affected the availability of snowmelt water in the irrigation channels or Kuhls in several parts of the Lahaul and Spiti districts. Similar kinds of incidents were reported in neighbouring Rwaling village the same year in the Lahaul valley.

It is also interesting to note that the melting of glaciers is also causing concerns about water-related hazards in the region. Many glaciers when recede, form a lake in the forefront of the glacier called a pro-glacial lake. In many cases, these lakes grow larger and outburst in the form of a glacial lake outburst flood (GLOF) causing destruction downstream. The glacial lakes are increasing in number very rapidly over the past few decades.

Challenges and way forward

The mountainous regions are always sensitive to the slightest change in the climate. The cold deserts of Lahaul and Spiti are at the forefront of experiencing the impacts of climate change. The IPCC (Intergovernmental Panel on Climate Change) has reiterated that the mountains are going to be affected disproportionately by climate change. There are reports of snowfall in many villages of Lahaul and Spiti in July this year, strongly indicating a shifting pattern in weather causing havoc in the region. With the growing trend of infrastructure development in the district, additional threats are posed to the fragile ecosystem of the area. Moreover, as domestic tourism experiences a surge in the Lahaul and Spiti District, there is a growing concern over unplanned and unregulated tourism. With the opening of the Atal tunnel connecting Manali to Lahaul Valley, tourism is bound to create an additional burden, especially on water resources.

With the warming of the planet by almost ~1.1° C compared to the pre-industrial revolution period and with predictions of further warming, the cryosphere is bound to lose its mass further at an increasing rate. Climatic mayhem is already taking place in the form of extreme weather events in the region. Being a high-altitude cold desert with very little rainfall and changes in snow and ice will only aggravate the water woes. The challenges posed by the melting cryosphere to the ecosystem and local community need to be addressed urgently by formulating measures considering the specific geographic conditions of the region. The need of the hour is adaptation measures such as river lift irrigation using solar pumps, snow-water harvesting, and artificial glaciers (ice-stupas) along with climate-resilient infrastructure for a sustainable future for the region.

Sandip Tanu Mandal is Research Associate, Mobius Foundation, New Delhi; and Jessica Gill is Senior Research Associate, Mobius Foundation, New Delhi. Views expressed are personal