Long-term monitoring of Himalayan glaciers essential to assess their health

Long-term monitoring of Himalayan glaciers essential to assess their health

Subject:  Geo

Sec: Geomorphology

Context:

Of the estimated 200,000 glaciers in the world, the Himalaya-Karakoram range is home to 39,660. Of these, only 24 have been consistently monitored for their glacier mass balance which indicates whether a glacier is growing or shrinking.

Monitor glacial health:

• It is crucial to monitor glacial health to understand the relationship of glaciers with climate and hydrology in the region.
• But high elevation and challenging atmospheric and climatic conditions make it difficult to monitor.
• Demarcating micro-climatic regions and monitoring a glacier in each of them as a representative of the whole region.
• The Himalaya-Karakoram (HK), a 2,500 kilometre-long mountain range, straddles the border between India in the east and across Bhutan, Nepal, northern India, and Pakistan in the west. This region is home to over 39,660 glaciers, covering 42,525 square kilometres across three river basins: Indus, Ganges and Brahmaputra.
• HK region has a much higher number of glaciers than any other mountain range on Earth.

Formation of glaciers:

• When snow falls and accumulates new layers over time, it gets compressed into large, thick masses of ice, forming glaciers.
• The upper part of the glacier — called the accumulation zone — receives precipitation in the form of snow, which accumulates over time.
• But in the lower part of the glacier — called the ablation zone — there is more melting of the snow and ice than accumulation.
• The balance between the accumulated and melted snow is known as the glacier mass balance, which determines the health of the glacier.
• Glaciers are crucial for downstream communities as they provide drinking water, or water for irrigation.
• Glaciers also regulate river flow and counter global warming.

Need to monitor glaciers:

• To understand how glaciers evolve — if glacier mass is growing, shrinking, or remaining the same — glaciologists say it is important to monitor glaciers on a yearly basis.
• The snow accumulation and the snow melt is measured throughout the hydrological year, to determine the glacier’s health.
• Of Nepal’s glaciers, which fall under the Central Himalayas, less than ten (only seven glaciers) are being monitored. Three of these — Mera glacier, Changri Nup glacier and Pokalde glacier — are located within the Dudh Koshi basin, in Nepal’s Khumbu area, home to Mount Everest.
• Mera glacier has been monitored since 2007 at least once a year (in November).
• Its mass balance series is the longest continuous field-based series in the Central Himalayas and second longest in the entire Hindu Kush Himalayan region.