Two glaciers in Nepal to disappear

KATHMANDU, Aug 3: Two glaciers in Nepal that shrank at an accelerated rate in the past 10 years compared to preceding decades will inevitably disappear from rising temperatures as no fresh snow supply is expected for them, a new research conducted by researchers from Japan´s Nagoya University says.

The masses of Yala glacier of Langtang Himal in central Nepal and the AX010 glacier of Shorong Himal in the Khumbu region shrank annually by 0.8 meters and 0.81 meters respectively in the 2000s, which was a significant acceleration from the 0.68 and 0.72 meters of shrinkage per year between 1970 and 1990, said findings of the research published in a journal of the National Academy of Sciences of the United States on Tuesday.

“If the trend since the 1990s continues for the Yala and AX010 glaciers, then the disappearance of these glaciers is inevitable because they are about to lose their accumulation areas; thus, no snow supply is expected for these glaciers,” says the research conducted by Koji Fujita and Takayuki Nuimura.

The researchers also found that while shrinking of glaciers has accelerated in humid environments, the opposite is true for those in arid environments. The shrinking of Rikha Samba glacier located in Kaligandaki Hidden Valley slowed from 0.57 meters per year between 1970 and 1990 to 0.48 meters per year in the 2000s.

“A comparison of the mass balance results and annual precipitation reveals that glacier wastage has been accelerated in humid environments but suppressed in an arid environment,” the research says.

Apart from environment, altitude also appears to play a role in the lifespan of glaciers, the researchers say. Rikha Samba is located at an altitude of 5,700 meters where loss of mass from melting could be compensated to some extent by collection of snowfall.

The Yala glacier and AX010, on the other hand, are located at lower altitudes of 5,400 meters and 5,200 meters respectively.

Comprehensive Study

This is among a few comprehensive researches on Nepal´s glaciers published so far as it relies on extensive ground-based information and not speculation and hearsay, said Pradeep Mool, action area team leader for Monitoring and Assessment of Ice and Water Resources at the International Center for Integrated Mountain Development (ICIMOD).

Apart from extensive field work, the researchers relied on global positioning systems and simulation models. The study that was conducted solely for academic purposes and not for activism was supported by Japan´s Ministry of Science and Technology.

“Also, the three glaciers are among the most widely researched in Nepal,” Mool said, underlining the importance of the findings. “Though it is not certain that other glaciers in the country will behave exactly in the same way as these three, it is by now clear that glaciers are generally shrinking due to warmer temperatures,” he added.

While loss of mass from melting of snow is one of the effects of rising temperatures, another effect is the formation of melt-water lakes that can burst through the natural dams, or moraines, leading to catastrophic flooding of valleys located below it.

Imja, Thulagi and Tsho Ropla are some of the glacial lakes that are believed to pose the threat of such flooding. A March 2010 reports of ICIMOD says detailed field investigations of the three glaciers showed that immediate threat of the lakes breaking their natural dams was found lower than previously reported, although they should be monitored regularly.

Nepal has faced glacial lake outburst floods (GLOFs) in the past. In 1981, Sunkoshi Hydroelectric Project was struck by flood resulting from the bursting of Baqu glacial lake in Tibet, China. And in 1985, an outburst flood from Dig Tsho glacial lake in Khumbu destroyed a nearly-completed Namche Small Hydel Project.