Centre warns of melting glaciers: What does it mean & why should we be worried

New Delhi: Most Himalayan glaciers that are studied are melting or retreating at differing rates in different places, according to the Central government.

It has been emphasised that melting glaciers due to climate change will not only harm the flow of the Himalayan river system but will also cause natural disasters.

The government responded to a parliamentary standing committee investigating Glacier Management in the Nation – Monitoring of Glaciers/Lakes, including glacial lake outbursts resulting in flash floods in the Himalayan Area.

On 29 March, the parliamentary standing committee report was tabled in the Lok Sabha.

The department of water resources, river development, and Ganga Rejuvenation stated that the Geological Survey of India has conducted studies on the melting of glaciers and assessed mass balance studies on nine glaciers as well as monitored the recession or advancement of 76 glaciers to explain the problem of incessant melting and retreating of Himalayan glaciers and the estimated volume loss of glaciers between the years.

“The majority of Himalayan glaciers have been recorded melting/retreating at differing speeds in different places,” the report stated.

The agency stated that melting glaciers due to climate change will not only harm the flow of the Himalayan river system but will also cause calamities such as glacier lake outburst flood (GLOF), glacier avalanches, landslips, and so on.

When asked about the potential negative consequences of melting glaciers, particularly on the ecology of the Himalayas, the department stated that melting glaciers may induce a shift in the Himalayan tree line as well as changes in plant phonological behaviour.

“It may have an influence on the livelihoods of mountain people as well as downstream inhabitants. Such alterations may hurt biodiversity conservation and Himalayan ecosystem services,” the report stated. The absence of data cooperation on hydrological information with neighbouring nations was highlighted by the parliamentary standing committee.

Regional cooperation urged

The committee highlighted that no formal agreement or convention exists with neighbouring countries for the exchange of glacier-related data for large-scale modelling and runoff dynamics.

According to the committee, regional cooperation is essential to develop a comprehensive and coordinated strategy that can successfully handle both the risk of glacier-related outburst floods and water management concerns.

“Because the threat posed by melting/retreating Himalayan glaciers transcends the national boundaries of the Himalayan nations, the committee is of the considered opinion that regional cooperation for seamless sharing of hydrological information/data on glacier movement/behaviour is very much warranted to formulate an effective and comprehensive response to the threat posed by melting of glaciers and for mitigating potential hazard situations,” it said.

As a result, the committee advised the department of water resources, river development, and Ganga Rejuvenation to pursue a bilateral or multilateral agreement with neighbouring Himalayan countries for the exchange of information and data on the changing state of glaciers and the hazards they pose.

Global warming heating up the Himalayas

When asked about the veracity of the claim that the Himalayas have become less cold over the last 50 years, with a substantiated decline in the number of extremely cold days and cold nights due to global warming and climate change, the department stated that, according to information provided by the environment ministry, climate change studies conducted exclusively over the Himalayas have revealed consistent warming in the current climate.

Trend analysis of cold days and cold nights at 16 stations in J&K and Himachal Pradesh found that the proportion of warm days is growing while the number of cold days is falling at the majority of the stations.

A similar pattern of increase/decrease in the percentage of warm/cold nights is also observed. Within 30 years, there has been a two to six per cent drop in cold days, it said.

Accelerated heterogeneous mass loss in Himalayan glaciers has been observed in studies led by the Geological Survey of India, Wadia Institute of Himalayan Geology, National Centre for Polar and Ocean Research, National Institute of Hydrology, Space Application Centre, and Indian Institute of Science.

What is a glacier?

A glacier is a huge, constant accumulation of snow, crystalline ice, sediment, rock, and other water that comes on land and goes downslope under the influence of its gravity and weight. Generally, glaciers do exist and are formed in places where:

· The average yearly temperatures are near the freezing point.

· Winter rainfall generates large accumulations of snow.

· The temperatures all through the year do not bring about the total loss of the preceding winter’s snow accumulation.

After many years, this constant accumulation of snow brings about the presence of a massive enough mass of snow. And the change from snow to glacier ice process starts.

Himalayan region warming faster than global average

The Himalayan mountains are sometimes known as the third pole because they contain the third-largest amount of glacier ice in the world, after Antarctica and the Arctic. According to climate experts, glacier melt affects agriculture and water supplies for millions of people in South Asia and will contribute to increasing sea levels, which endanger coastal towns around the world.

The Himalayan glaciers have lost almost 40% of their area in the previous couple hundred years, or an estimated 390 to 586 cubic kilometres of ice—enough to raise world sea levels by 0.92 to 1.38 millimetres.

There are thousands of glaciers in the Hindu Kush Himalayan region, and there will be glacial melt anomalies. The glaciers in the eastern half of the region are often lower in height than those in the western part, making them more prone to melting. There have also been some glacial surges in the Karakoram region, which is home to several high-altitude glaciers, prompting speculation of a “Karakoram Anomaly.”

As the ice cover melts, it exposes more areas to solar radiation, allowing for higher heat absorption. Because ice reflects light, as the ground becomes more exposed, it heats up. Because many glaciers in the HKH region are coated in debris, the effect is less dramatic than in locations such as the Arctic.

Which glaciers in India are melting?

According to the ministry of earth sciences, the average retreat rate of Hindu Kush Himalayan glaciers is 14.9-15.1 meters per year, with Indus glaciers retreating at 12.7-13.2 meters per year, Ganga glaciers retreating at 15.5-14.4 meters per year, and Brahmaputra glaciers retreating at 20.2-19.7 meters per year.

The Wadia Institute of Himalayan Geology discovered that the Dokriani Glacier in the Bhagirathi basin has been retreating at 15-20 meters per year since 1995, whereas the Chorabari Glacier in the Mandakini basin has retreated at 9-11 meters per year between 2003 and 2017.

Similar phenomena are taking place in the Satluj River watershed. The Divecha Centre for Climate Change at IISc Bangalore researched the glacier and discovered that glacial melt contribution will increase until the middle of the century, then diminish. “Numerous little glaciers located in the Satluj basin’s low altitude region imply a considerable loss in the area until the middle of the century, producing a scarcity of water during the dry summer season,” according to climate change experts.

In the short term, glaciers in the Hindu Kush Himalayan region are anticipated to lose 10-30% of their bulk by 2030. This proportion is predicted to rise to 25-35% by 2050. Long-term glacial mass loss is expected to reach 35% in the Karakoram, 45% in the Pamirs, and 60-95% in the eastern Himalayas if world governments do not enact ambitious emissions-reduction programmes. All of these statistics are based on a scenario with mild emissions (RCP 4.5). Longer-term forecasts vary significantly due to different emission scenarios and modelling approaches.

Why are the glaciers melting so rapidly?

There is scientific agreement that human-caused climate change has resulted in faster ice melts from glaciers and polar ice sheets, as well as higher global ocean temperatures.

Researchers believe that changes in the South Asian monsoon may have also contributed to the Himalayan ice loss.

Regrettably, the glaciers of the Hindu Kush Himalayas are also dealing with a new issue: black carbon. This is mainly smoke from nearby lowland fires that rises into the air and falls on glaciers. Black carbon absorbs solar radiation more quickly due to its dark colour. A variety of human activities, including biomass burning, brick manufacturing, and coal-fired power plants, emit black carbon and other short-lived climate pollutants, including dust and aerosols. These pollutants not only discolour the glaciers, but they can also cause warming of the air mass, resulting in greater temperatures surrounding the cryosphere and melting of its ice.

The existence of the cryosphere has resulted in consistent water flows throughout the Hindu Kush Himalayan region. These flows, however, are shifting as the frozen water in glaciers, snow, and permafrost melts at unprecedented rates.

What is the cryosphere?

The term cryosphere refers to the areas of the planet where most of the water is in a frozen form: that is, the polar regions and high mountains. In the Hindu Kush Himalayas, the world’s highest mountain range, frozen water exists in the form of glaciers, ice caps, snow, permafrost, and river and lake ice.

Why is this a cause for concern?

The melting of Himalayan glaciers is a major source of concern since it will have a massive impact on the water supply for rivers that rely on these glaciers. Because of variations in discharge, flash flood, and sedimentation, continuous melting will modify glacier basin hydrology, the downstream water budget, and the influence on hydropower facilities.

“The increased risk associated with glacier hazards as a result of increased number and volume of glacier lakes, faster flash flood, and glacial lake outburst floods, while also having an impact on agro practices in the high Himalayan region,” said climate change experts.

A rise in glacial lake outburst floods (GLOFs) is one effect that can be foreseen.

While individual GLOFs are impossible to anticipate, it is apparent that their frequency will increase as the climate warms. Glacial lakes in the Hindu Kush Himalayan region have grown in both quantity and extent during the 1990s. Given the geographical variance in elevation, the biggest rise has occurred in the Hindu Kush Himalayas’ eastern and central parts.

What is a GLOF?

A glacial lake is formed as the ice in a glacier melts and water fills up the space between the glacier and the moraine—the wall of debris—in front of the glacier. As the pressure of water increases, due to melting or a trigger such as a large ice avalanche into the lake, the lake may breach the containing moraine walls, potentially driving millions of tonnes of water, boulders, and debris before it.

GLOFs can be disastrous because flash floods can devastate downstream communities with little notice. GLOFs can potentially endanger long-term infrastructure such as dams, given the number of hydropower projects in the region.

How can we prevent glaciers from melting?

· Buy energy-efficient appliances.

· Recycle.

· Plant trees.

· Use alternative energy sources.

· Make your home more energy efficient by closing drafts and making sure it is properly insulated.

· Since the production of livestock products is much more intensive, eating lesser meats can make a difference too.

· Reduce water waste.

· Use solar energy.

· Understand individual carbon footprint.

· Become more informed.

Inputs from PTI