By Aniruddha Ghosal
A portion of the Nanda Devi glacier broke off in Uttarakhand’s Chamoli district on February 7, triggering an avalanche and a deluge in the Alaknanda river system that washed away hydroelectric stations and caused another disaster. At least 38 people have died and over 200 people are still missing.
When Ravi Chopra saw the devastating deluge of water and debris crash downstream, his first thought was that this was exactly the scenario that his team had warned the Indian government of in 2014. The deluge first smashed into a small dam, gathering more energy as it grew heavier from the debris it collected along the way. Then, it smashed into a larger, under-construction dam and gathered even more energy.
Chopra and other experts had been tasked by the Supreme Court to study the impact of receding glaciers on dams. They had warned that warming due to climate change was melting the Himalayan glaciers and facilitated avalanches and landslides, and that constructing dams in the fragile ecosystem was dangerous. “They were clearly warned, and yet they went ahead,” said Chopra, director of the non-profit People’s Science Institute.
Scientists first suspected that a glacial lake had burst. After examining satellite images, they now believe that a landslide and avalanche were the more likely causes. It isn’t clear whether the landslide induced an avalanche of ice and debris, or whether falling ice resulted in the landslide, said Mohammad Farooq Azam, who studies glaciers at IIT, Indore.
What is known is that mass of rock, boulders, ice and snow came crashing down a two-kilometre near vertical mountain slope. Scientists are also trying to figure out if the heat produced due to friction would be enough to melt the snow and ice to result in the flood of water.
Experts say that the disaster underscores the fragility of the Himalayan mountains, where the lives of millions are being altered by climate change. Even if the world meets its most ambitious climate change targets, rising temperatures will melt away a third of the Himalayan glaciers by the end of the century, states a 2019 report by the International Centre for Integrated Mountain Development (ICIMOD).
Whether this particular disaster was caused by climate change isn’t known but climate change can increase landslides and avalanches. As glaciers melt due to warming, valleys that were earlier crammed with ice open up, creating space for landslides to move into. In other places, steep mountainous slopes may be partially “glued” together by ice frozen tightly inside its crevices. “As warming occurs and the ice melts, the pieces can move downhill more easily, lubricated by water,” explained Richard B Alley, a professor of earth sciences at Pennsylvania State University.
With warming, ice is also essentially becoming less frozen. Earlier its temperature would range from minus 6 degrees Celsius to minus 20 C and it is now minus 2 C, said Azam. The ice is still frozen, but is closer to its melting point, so it takes less heat to trigger an avalanche than some decades ago, added Azam.
Glacial Lake Bursting
Another threat is that of a glacial lake bursting, the first suspected cause of the disaster last Sunday. The hazard posed by these expanding lakes can’t be ignored, said Joerg Michael Schaefer, a climate scientist, who specialises in ice and especially Himalayan glaciers, at Columbia University.
The water the lakes release into rivers contains the energy equal to “several nuclear bombs” and can provide clean, carbon-free energy through hydropower projects, Schaefer said. But it’s dangerous to set up power plants without looking uphill and mitigating the risk by siphoning water from the lakes to control levels, he said. “The brute force of these things is really mind blowing,” especially if they break, he said. “You cannot tame that tiger. You have to prevent that.”
With the onset of climate warming about 1850-1905 (generally considered as the end of the Little Ice Age), many glaciers throughout the world, including in the Hindu Kush-Himalayan (HKH) region, began to thin and their termini to retreat. This has led to the creation of many glacial lakes. The HKH region is also one of extreme seismic instability. Earthquakes could act as major triggers for glacial lake outbursts (ICIMOD).
Uttarakhand has the second-highest potential for generating hydropower in India, but experts say that solar energy and wind energy offered more sustainable and less risky alternatives in the long-run. Development was needed, but experts said such projects should take into account the ecological fragility of the mountains and the unpredictable risks posed by climate change.
Development plans need to “go along with the environment” and not against it, stressed Anjal Prakash, a professor at the Indian School of Business, who has researched into the impacts of climate change in the Himalayas for the Intergovernmental Panel on Climate Change. “Climate change is here and now. It is not something that is going to happen later on.” With inputs from Agencies
Melting of Himalayan glaciers has doubled since the start of the 21st century due to rising temperatures, losing over a vertical foot and half of ice each year since 2000, which is double the amount of melting that took place from 1975 to 2000.
This potentially threatens water supply for hundreds of millions of people in countries, including India, according to a study by Columbia University’s Lamont-Doherty Earth Observatory, published in 2019. The analysis, spanning 40 years of satellite observations across India, China, Nepal and Bhutan, indicates that climate change is eating the Himalayan glaciers.
“This is the clearest picture yet of how fast Himalayan glaciers are melting over this time interval, and why,” said Joshua Maurer, a PhD candidate at Columbia University. The glaciers may have lost as much as a quarter of their enormous mass over the last four decades, said Maurer, lead author of the study. The study synthesised data from across the region, stretching from early satellite observations to the present.
The data indicates that the melting is consistent in time and space, and that rising temperatures are to blame. Researchers analysed repeat satellite images of some 650 glaciers spanning 2,000 kilometres from west to east. They found that from 1975 to 2000, glaciers across the region lost an average of about 0.25 metres of ice each year in the face of warming.
Asian nations are burning ever-greater loads of fossil fuels and biomass, sending soot into the sky, adding much of it on snowy glacier surfaces, where it absorbs solar energy and hastens melting. The Himalayas are generally not melting as fast as the Alps, but the general progression is similar.
Can we afford big dams?
The damage of four hydropower stations, including the NTPC-owned Tapovan Vishnugad, the private project of Rishi Ganga, Pipal Koti of state-owned THDC, and Jaypee Group’s Vishnuprayag has brought construction of big dams into sharp focus. Uttarakhand’s main source of development is hydel power and its potential is around 20,236 Mw. Highlighting this, a World Bank report has termed it as the State’s most important strategic assets.
But given its rather fragile ecology, are big dams in Uttarakhand sustainable? According to the Indian Metrological Department, the Bureau of Indian Standards categorises Uttarakhand as a V seismic zone, the most active zone. The Indian plate, a part of the Indo-Australian plate, colliding with the Eurasian plate, has created several fault lines, making the region earthquake prone.
That said, new technologies are being consistently developed to overcome this hazard. A position paper by the International Water Power & Dam Construction, states that “technology is available for building dams and appurtenant structures that can safely resist the effects of strong ground shaking. Storage dams that have been designed properly to resist static loads prove to also have significant inherent resistance to earthquake action. Many small storage dams have suffered damage during strong earthquakes. However, no large dams have failed due to earthquake shaking”.
Yet, the paper adds that “there are still uncertainties about the behaviour of dams under very strong ground shaking, and every effort should be made to collect, analyse and interpret field observations of dam performance during earthquakes”.
The way forward for Uttarakhand is Small Hydro Power (SHP) projects. Projects up to 25 Mw station capacities are categorised as SHP, and these provide clean energy. Besides requiring minimal submergence, rehabilitation and minimal impact to the environment, they accrue other advantages like promoting local industries in remote areas and assisting self-employment. For example, in the remote area of Badrinath, power supply is through an SHP.
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