While the coronavirus induced lockdown across countries helped the environment recuperate, the decades of overutilisation, pollution, and carbon emission have effected an increase in the volume of glacial lakes by 50 per cent. These lakes have been formed by the melting of ice due to unchecked global warming.

In the largest-ever study of glacial lakes published in Nature and Climate Change, researchers observed that the volume of lakes formed by the melting of glaciers jumped by 50 per cent since 1990 as glaciers retreat due to climate change.

The study was conducted using satellite data collected by Nasa, spanning over three decades.

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Glacial lakes and their impacts

The study will help researchers estimate the rise in sea level and create plans to aid people likely to be affected downstream of these lakes, which are mostly unstable.

NASA in a statement said that the glaciers are retreating on a near-global scale and this study provides scientists with a clearer picture of how much of this water has been stored in lakes. Dan Shugar of the University of Calgary in Canada, lead author of the research said, “We have known that not all meltwater is making it into the oceans immediately. But until now there was no data to estimate how much was being stored in lakes or groundwater.”

Greenland

Greenland lost significant ice mass in 2019. (NASA)

The study estimates current glacial lake volumes at about 37.4 cubic miles (156 cubic kilometers) of water.

It is to be noted that the glacial lakes are not stable like the lakes in which most people are used to swimming or boating as they often contain ice boulders or glacial sediment known widely as moraine. The moraine is composed of loose rock and debris that is pushed to the front and sides of glaciers. These lakes can be quite unstable and can burst their banks or dams, causing massive floods downstream affecting people and property located in the vicinity. These kinds of floods from glacial lakes, known as glacial lake outburst floods, have been responsible for thousands of deaths over the years, as well as the destruction of infrastructure, and livestock.

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India’s tryst with glacial lakes

According to the Central Water Commission of Ministry of Jal Shakti, there are 2028 glacial lakes and water bodies in the Himalayan region catchment which contributes to rivers flowing across the country. While the Brahmaputra river has the maximum number of glacial lakes, the Ganga river forms 178 such lakes in its course.

The devastating 2013 Kedarnath floods in Uttarakhand were results of glacial lake outbursts in the region triggered by heavy rains.

On the need to closely monitor these glacial bodies, the Commission said, “these lakes have immense potential of flooding in downstream areas, causing disastrous consequences due to the release of large volumes of water in a very short interval of time. Most often, the consequences arising out of such situations are highly unpredictable primarily due to lack of availability of sufficient data regarding rainfall intensity, location of the landslide, impounded volume and area, and physical conditions of lakes.”

Kedarnath

2012 Kedarnath floods was result of glacial lake outburst. (Shutterstock)

A global research

The global research was conducted as part of a collaboration from governments and universities in Canada, the United States, and the United Kingdom, working under a grant from Nasa’s High Mountain Asia Program. The initial area of study for the research was two dozen glacial lakes in Asia, the Tibetan Plateau, and the surrounding mountain ranges including the Himalayas. However, the team, widened its focus area using satellite imaging and other remote-sensing data from the Landsat satellite missions.

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“We wrote scripts in Google Earth Engine, an online platform for very large analyses of geospatial data, to look only at High Mountain Asia, and then decided to look at all glacial lakes in the world,” Shugar said. “From there, we were able to build a scaling relationship to estimate the volume of the world’s glacial lakes based on the area of this large population of lakes,” he further added.

The team looked at the data in five time-steps beginning with 1990 to examine all the glaciated regions of the world except Antarctica and analyse how these lakes changed over that period.

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