Himalayan glacial lakes saw area expansion from 2011 to 2024

Context: Glacial lakes and other water bodies across the Himalayan
region saw a 10.81 per cent increase in area from 2011 to 2024 due to climate
change, signalling a heightened risk of glacial lake outburst floods (GLOFs),
according to a government report. The Central Water Commission’s (CWC) report, which
was accessed by PTI, states that with a 33.7 per cent expansion of the surface area,
the lakes in India experienced an even more substantial rise. It also
identified 67 lakes in India that witnessed an over 40 per cent increase in
surface area, placing them in the high-risk category for potential GLOFs. Ladakh,
Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh showed the most
notable expansions, signalling a heightened risk of GLOFs and the need for
intensified monitoring and disaster preparedness.

Key points

·      
Overview: Recently, satellite monitoring data has shown a large
expansion in glacial lakes between 1984 and 2023 in the Himalayan region, which
has posed an alarming situation for the downstream areas.

·      
Findings: Of the 2,431 lakes larger than 10 hectares identified
during 2016-17, 676 glacial lakes have notably expanded since 1984.

·      
Types and
Number of Glacial Lakes in Himalayas: Moraine-dammed (307)- They are formed when piles of rocks and
debris (moraines) left behind by retreating glaciers block valleys, creating
natural dams that hold back meltwater.

Ice-dammed (8)- They are formed when a glacier itself acts as a dam, blocking the flow
of meltwater.

Erosion (265)- These lakes occupy depressions carved directly into bedrock by
glaciers. And other 69 glacial lakes.

·      
Causes of
Expanding Glacial Lakes in Himalayas: Global Warming- It is causing temperatures to rise in the
Himalayas, leading to increased melting of glaciers. This meltwater feeds into
existing glacial lakes, causing them to expand in size.

Retreating Glaciers- As glaciers melt, they not only contribute water to the lakes but also
expose new land surfaces. This allows for the formation of new glacial lakes.

Weakening Moraines- Glaciers are often dammed by natural walls of rock and debris called
moraines.

Increased Precipitation- Changes in precipitation patterns, including increased rainfall and
snowfall in the region, can contribute to the expansion of glacial lakes by
providing more water to fill them.

Permafrost Thaw- Permafrost, which is soil that remains frozen year-round, acts as a
natural barrier to water drainage.

Human Activities- Infrastructure development, such as roads and hydropower projects, can
alter the natural drainage patterns of glacial lakes, leading to their
expansion.

·      
GLOF in
India: In June 2013, Uttrakhand had
received an unusual amount of rainfall leading to the melting of the Chorabari
glacier and the eruption of the Mandakini River. In August 2014, a glacial lake
outburst flood hit the village of Gya in Ladakh. In February 2021, Chamoli
district in Uttarakhand witnessed flash floods which are suspected to have been
caused by GLOFs. In October 2023, the South Lhonak Lake, a glacial lake located
at an altitude of 17,000 feet in the state's northwest, experienced a rupture
because of continuous rainfall.

·      
Way
forward: Climate Change Mitigation-
Addressing the root cause of glacial melt and retreat by reducing greenhouse
gas emissions is crucial.

Early Warning Systems- Developing and implementing early warning systems for monitoring of
glacial lakes, weather forecasting, and communication networks to disseminate
timely alerts to at-risk communities.

Engineering Measures- Implementing engineering measures to stabilize and manage glacial lakes
can help reduce the risk of GLOFs.

Natural Infrastructure- Restoring and conserving natural ecosystems, such as wetlands and
forests, can help regulate water flow. These natural infrastructure solutions
can also provide additional benefits, such as habitat conservation and carbon
sequestration.