Renu Sud Sinha
The infamous Indian summer has started prematurely, according to recent IMD reports, with a very short winter last year. In fact, December 2022 and February this year have the dubious distinction of being the hottest in the past 122 years. As the subcontinent stares at intense heatwaves, climate scientists are worried that extreme temperatures will severely impact not only the population but the environment and the economy as well.
Water resource system can go haywire
A recent assessment says that by the end of this century, at least two-third glaciers will disappear, affecting the livelihood and water resource system for India’s 1.3 billion population. Dr Anjal Prakash, Climate Scientist
“Rising temperatures in the past few years have put the ecologically fragile Himalayan zone at a very high risk. All the glaciers in the Himalayas are melting or in a state of retreat, with the rate of retreat varying across various climatological regions,” says Dr Irfan Rashid, senior assistant professor, Department of Geo-informatics, University of Kashmir. “Kolahoi, the largest glacier of Kashmir valley’s Jhelum basin, is one of the fastest retreating glaciers as temperatures rise due to global warming. Its snout is retreating 55 metres per year since 2008,” adds the researcher.
Dr Anjal Prakash, research director, Bharti Institute of Public Policy, Indian School of Business, Hyderabad, who has been part of two reports by the Intergovernmental Panel on Climate Change (IPCC), agrees that global warming is the major reason why glaciers are melting very fast. He was part of the special 2019 report on oceans and cryosphere that gave this conclusion. “A recent assessment says that by the end of this century, at least two-third glaciers will disappear. That’s quite alarming because they are the lifelines that support the livelihood and water resource system for India’s 1.3 billion population. Ten major Indian rivers originate from the Himalayas. Rivers in North are extensively fed by glaciers. Thirty per cent of the Indus’ water, one of the three major rivers, besides the Ganga and the Brahmaputra that feed India, comes from glacial melt during summer and this glacial melt also provides its base flow. It is imperative that we protect our glaciers.”
Rising winter temperatures, shifting snowfall patterns and a shortening winter are only hastening the melting process. “We studied the Climatic Research Unit (CRU) data for the last over 100 years from 1900 onwards and observed that since 1950, the winter temperatures (November-February) started rising gradually. However, since 2000 onwards, the rise has been rapid, while summer temperatures (May-September) have remained more or less the same,” says Dr Manish Mehta, a geologist at Dehradun's Wadia Institute of Himalayan Geology.
Earlier, the glaciers melted only during the summer. Winter was the accumulation or rejuvenation period. “With rising winter temperatures, glaciers are melting throughout the year,” adds the geologist.
This has affected the rainfall pattern as well. Summer rain is more while winter precipitation has decreased. “Earlier, snowfall happened from November to January. Now the period has decreased to two months and shifted to the warmer months of January and February. The snow that fell during the colder months of November-December was more stable and lasted longer,” adds Mehta who led the team that did a comparative study on differential glacial retreat patterns in the Pensilungpa and Durung-Drung glaciers in Leh.
This will also have an impact on the seasonal availability of water in spring and summer both, says Dr Thamban Meloth, Director, National Centre for Polar and Ocean Research, Goa. “Early snow melts in spring, while glacial melt happens in peak summer. As the snow cover vanishes, glaciers will melt more. This shift will impact human settlements affecting agriculture and horticulture practices as well as affecting economy.”
The topography of the Himalayas also makes it more vulnerable to global warming. “The warming is amplified at higher elevations because the reflected radiation of the sun, as compared to plain areas, is less as it gets trapped due to the steep topography,” says Dr Farooq Azam, assistant professor, IIT, Indore, whose research papers on glaciers have been published in various international science journals.
As glaciers lose mass and thin, the snow cover is also shrinking and the volume decreasing. “The wastage or melting rate has nearly doubled since 2000. This has some far-reaching implications for downstream water availability. Initially, as glaciers melt due to increasing temperatures, there will be more discharge or water for a certain time period. But as the volume and snow cover shrink, the discharge will decrease,” says Dr Azam, who led a study conducted by a team from IIT, Indore, on the glacial hydrology of the Himalayan rivers. The study, published in the journal ‘Science’, projects that there will be more and more water volume in rivers like Indus, Ganga and Brahmaputra till the 2050s and will decrease thereafter.
This excessive flow will initiate flood-like situations downstream. “Last year, too, we had similar heatwave conditions in the subcontinent causing more glacial melting. At the same time, there were heavy rains. These combined factors triggered one of most devastating floods in Pakistan last year,” adds Azam. The flash floods in Uttarakhand in June 2013 had happened for similar reasons. An unusual amount of rainfall had caused melting of the Chorabari glacier and flooded the Chorabari lake, causing eruption of the Mandakini river. The death toll was over 6,000 and the financial loss over $500 million.
Chamoli disaster in February 2021 was another tragedy that happened due to shorter winters, a premature summer and excessive precipitation. A week of heavy precipitation was followed by an unusually warm day. A portion of glacier broke off from Ronti peak, causing a huge avalanche and debris flow, killing 200 persons and damaging two major hydro-power projects.
Formation of glacial lakes is another major hazard. These lakes form when receding glaciers erode the terrain and leave depressions that are filled by either the melting ice or precipitation. These unstable water bodies, dammed by debris or moraines, can cause flash floods. This phenomena, called glacial lake outburst flood (GLOF), is the release of meltwater from a moraine-dam or ice-dam glacial lake due to dam failure. Their number and size is increasing with passing years.
Snow avalanches, rock fall, landslides, climatic extremes, cyclones, etc. are the other dangers associated with glacial melt and global warming. They all pose a huge threat to downstream communities.
Himachal Pradesh has also seen a decline in the area under glaciers, though the number of glaciers as well as the number of glacial lakes have increased, enhancing the potential threat of flooding in downstream areas. “Since 2001, the area has decreased from 221 sq km to 216 sq km while the number of glaciers has gone up from 180 to 187. Due to fragmentation and melting of big glaciers, the number of small glaciers has increased,” says Dr SS Randhawa, Principal Scientific Officer, State Centre on Climate Change, HP.
The snow cover in HP shrunk by 18.5 per cent until 2020-21, says Lalit Jain, Director, Department of Environmental Science and Technology, HP. This could adversely impact the hydro-power generation, one of the main revenue generating sectors with a potential of 27,000 MW in its five major river basins.
The Sixth Assessment Report of the IPCC has already warned of extreme precipitation in major mountainous regions with potential threats of floods, landslides and lake outbursts, adds Prakash, who was part of this report.
Glaciology is still in its nascent stage in India. “Glaciers show change over several decades. To understand their behaviour, we need data going back several decades but we only have data going back 20 years. The number of experts was quite less, though things are improving now, as many government bodies, private organisations, research groups and universities are working in this field,” says Dr Argha Banerjee, Deputy Chair, Earth and Climate Science, Indian Institute of Science Education and Research, Pune.
There are other logistical issues. “Glaciers need long-time monitoring but most projects are of three to five years and funding is available accordingly,” adds Banerjee.
There are other challenges. The number of groups may have been growing but there is hardly any coordination or sharing of data among them, says a researcher on condition of anonymity. Also, there is no early warning system in place, he adds.
The coordination is lacking because glaciology is multi-disciplinary science involving many other aspects, including hydrology, disaster management, etc, justifies Meloth.
He says having such a system in place in the Himalayas is a Herculean task. “The mountain system is too steep on the Indian side. The altitude also varies from 2,000 ft to over 5,000 ft. Putting an early warning system and maintaining the equipment installed for a long time is quite difficult in the Himalayas’ extreme conditions. For an early warning system to succeed, real time data is needed, which requires a large number of monitoring stations,” adds the director.
“We also need more capacity building and trained scientists in field glaciology. At present, most research work is happening through remote sensing. There is also a need for a wider monitoring process where more large glaciers are being studied across various climatological zones of the Himalayas,” suggests Azam, who has initiated a process-based field investigation on Durung Drung Glacier, in Ladakh, the biggest glacier under field observations, in the whole of Himalayas.
There are some man-made hazards as well such as unchecked development. “Development is having a negative impact, particularly in the Himalayan region. We need a balance between development and ecology. Hydro power projects can cause more harm in the fragile Uttarakhand region than in Kashmir or Himachal.”
The solution lies with policy-makers, says Prakash. “Climate change was added later to the Ministry of Environment and Forests. We need a separate ministry for climate change, and not an add-on one. If not a separate ministry, we need a separate coordination body at least. People participation and public awareness matter but ultimately the responsibility lies with the government. Scientists are doing their work. All information needed to make good policies is out there. Now policymakers need to listen to the science and not politics of the day,” Prakash adds.
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