Fears of glaciers vanishing exaggerated, says study

Cato Institute paper says Himalayan melt has little impact on rivers

Fears of global warming rapidly melting Himalayan glaciers that feed major river basins in India are unfounded, according to a paper published by the Us-based think tank Cato Institute on Tuesday.

The report titled False Alarm over the Retreat of the Himalayan Glaciers, co-authored by Swaminathan S Anklesaria Aiyar and Vijay K Raina, says that the importance of glacial melt in river flows has been grossly exaggerated.

In 2007, the Intergovernmental Panel on Climate Change (IPCC) published a report that said, “Glaciers in the Himalayas are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high.”

Raina, who was director general of the Geological Survey of India, wrote a report titled Himalayan Glaciers: A State-of-art Review of Glacial Studies, Glacial Retreat and Climate Change in 2009, after he was appointed by the government of India.

The new Cato Institute paper points out that Raina’s report highlighted the formation of glaciers and their melting. “In the 20th century, the average annual retreat was around five metres (16 feet) until the late 1950s, but then it accelerated fast until the late 1980s, reaching up to 30 metres (98 feet) in some years for the Gangotri Glacier, and even more for some smaller glaciers,” it observed, and added that “glacial retreat decelerated from the 1990s onward, the period when global temperatures have been rising”.

In 2010, the IPCC admitted that they had erred in their claim.

Raina’s report also argued that the main causes of glacial melting “are very local phenomena”.

One of the examples it cited to illustrate the point was that of the Siachen Glacier, the biggest in the Himalayas and over 70 km long (44 miles). “It advanced 700 metres (2,297 feet) between 1862 and 1909, retreated 400 metres (1,312 feet) between 1929 and 1958, and then hardly retreated at all in the next 50 years.”

Raina’s study gave estimates of the annual retreat of the Gangotri Glacier up to 2007–2009. The Cato paper also refers to a 2017 study by Dhruv Sen Singh et al (Pattern of Retreat and Related Morphological Zones of Gangotri Glacier, Garhwal Himalaya, India) that extended the data on retreat until 2015. The retreat of the Gangotri Glacier, which is the source of the Ganges, was relatively modest at a little over 10 metres (33 feet) per year between 1935 and 1956, the 2017 study noted. After that it accelerated, with one study estimating an average of as much as 40 metres (131 feet) per year during 1962– 1982, leading to “alarmist speculation”, it added.

“Singh and his co-authors estimate that the glacier’s retreat averaged 17.44 metres (57.22 feet) per year during 1976–1990; then it came down to 12.55 metres (41.17 feet) per year during 1990–2001; and then it fell further to 10 metres (33 feet) per year between 2001 and 2015.”

The new paper by Aiyar and Raina also refers to satellite-based data collected by the Indian Space Research Organisation (ISRO) on the Himalayan glaciers for a few decades, which covers the Indus, Ganges, and Brahmaputra basins.

One of its studies between 2004 and 2011 identified 34,919 glaciers spread over 75,779 square km (29,258 square miles) of glaciated area in the Himalayan region. It also monitored the advance and retreat of 2,018 glaciers from 2000-2001 to 2010-2011, the results of which were published in the journal, Current Science. From ISRO data it emerged that altitude is a key factor in the amount of glacial melt. “Glaciers at low altitudes face relatively high atmospheric temperatures and so melt faster, while those at high altitudes are colder and melt more slowly, or in some cases, advance,” the Cato paper says.