Glaciers are considered to be a water tower for fresh water supply in the world and have become one of the most important subjects of discussion in the contemporary climate change debate.
Glaciers also work as a source of authentic observational information for exploring and determining the intensity of climate change as they are the most sensitive natural bodies to be affected by global temperature variations. In recent years, the most visible indicator of rising global temperature is the rapid melting of glaciers which has resulted in a rapid decrease in the deposit and spatial cover of the cryosphere. The decrease in cryosphere or ice mass balance has coincided with the formation and expansion of a large number of glacial lakes beneath the loose moraine of high altitude.
The accumulation of water in these lakes can lead to a sudden outburst, creating a high velocity flood reinforced by the breach of unstable moraine dams down the stream. This always leads to the discharge of huge amounts of water and debris which, in turn, transforms into disastrous floods. This kind of flood due to lake outburst is called Glacial Lake Outburst Flood (GLOF) which unleashes devastation upon the downstream populations of mountainous regions.
A number of such GLOF events have been reported in various parts of Gilgit-Baltistan and Khyber Pakhtunkhwa in the last few decades. In the GLOF phase I project of the government of Pakistan, some 33 potentially high-risk lakes were identified across GB and the mountainous region of KP, calling for some immediate action to minimize risk of an impending catastrophe.
It is, therefore, of utmost importance that the potential hazards of GLOF as well as its mitigation and adaptation strategy is integrated into the National Climate Change Policy Framework. Some of the mitigation plans from Phase I of the GLOF project were included in the National Climate Change Policy only as passing comments twice in the 38-page document. With such passing mentions only, the National Climate Change Policy does not reflect the scale and intensity of risks associated with GLOF and the required mitigation and adaptation plans.
Having said that, in a timely realization, GLOF mitigation and adaptation action plans are being integrated into the Gilgit-Baltistan Climate Change Strategy. This makes more sense given the contextual relevance of GLOF to Gilgit-Baltistan and in averting the anticipated disasters which are likely to bring enormous damages to lives and livelihood of the mountain communities.
It has become an established fact that the rising temperatures have melted glaciers, creating a huge number of glacial lakes in Gilgit-Baltistan as well as other mountainous areas in the province of KP. The findings from phase I of the GLOF project suggest that the outburst flooding events have threatened over seven million people in the mountainous regions of the country. The findings also call for enacting early warning systems, modifying physical infrastructure and formulation of inclusive disaster management policies to help reduce risk, protect local communities and provide functioning early warning against devastating flood events.
It is estimated that the melting of glaciers in the Hindukush, Karakoram and Himalayan regions due to rising temperatures has created 3,044 glacial lakes in GB and KP. All these glacial lakes pose potential risks but 33 of them are considered highly hazardous and likely to result in glacial lake outburst floods any time soon. If this flooding happens, it will release millions of cubic meters of water and debris in just a few hours, resulting in the loss of lives, destruction of property and infrastructure, and severe damage to livelihoods. The only viable solution to reduce the impending damages is to build locally feasible engineering structures including delay action dams, ponds, gabion walls, spillways, tree plantation and drainage systems.
It will be equally important to develop disaster management action plans, which must include community awareness raising campaigns as their integral part. They should also include the installation of weather monitoring stations, flood gauges, hydrological modelling and early warning systems to enhance the local capacity of responding to the flood scenarios
As the global temperature continues to rise, the high mountainous glacial environment becomes exposed to unprecedented changes with tremendous impact on lives and livelihoods, in particular. During the last one century only, the global average temperature has increased by approximately 0.75 C and in the last four decades, the average temperature in GB has gone up by 0.14 to 0.7 C per decade. It is estimated that, from 1960 to 2019, the rising average annual temperatures have resulted in an unprecedented reduction in the glacial surface in the Upper Indus Basin.
The shrinking, receding and retreating of glaciers along with the lowering of glacier surfaces became visible after early 1960, with rapid changes after 2000. This phenomenon of chaotic changes coincided with the formation and expansion of many moraine-dammed glacial lakes, giving birth to frequent events of GLOF. The frequency with which these GLOF events start to occur is alarmingly high. According to estimates by ICIMODD and UNDP, the mountainous regions of the Himalayas, Hindukush and Karakoram faced at least one disastrous GLOF event each year during the last one decade.
In the case of both GB and the mountainous regions of KP, GLOF has not only brought about human casualties in the narrow gorges, it has also damaged physical infrastructure including settlements, roads, farmlands, orchards, forests, cattle-sheds, water mills, bridges and hydro-powers. Even if these structures were not directly affected by GLOF, they became exposed to high risk due to the active landslides after the GLOF-induced land erosion, and collapse of surrounding or adjacent land.
Full-scale mitigation work on potentially disastrous glacial lakes is very expensive – mitigation work on a glacial lake costs more than $3 million on average. There are more than 3000 such glacial lakes in the mountainous regions of the Himalayas, Hindukush and Karakorum. Depending upon their potential of disaster, more than 50 percent of these lakes pose immediate or distant threats to the lives and livelihood of the people of GB and KP.
Physical mitigation work on this increasing number of lakes is imprudent if not humanly impossible for a poor country like Pakistan. Therefore, the best strategy to effectively minimize the adverse impact of GLOF in the mountainous regions must entail an elaborate awareness raising program as well as technology intensive and cost-efficient adaptation measures. I will discuss the ways of reducing vulnerabilities, gauging real-time risks and the monitoring mechanism of GLOF in some other article soon.
The writer is a social development and policy adviser, and a freelance columnist based in Islamabad.
Email: ahnihal@yahoo.com
Twitter: @AmirHussain76
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