RISING MERCURY IS MAKING NEPAL GLACIERS VULNERABLE

Changing nature of glaciers and glacial lakes make the Himalayas one of the most climate vulnerable regions on the planet. RIJAN BHAKTA KAYASTHA, a glaciologist at the Himalayan Cryosphere, Climate and Disaster Research Center, Kathmandu University in Nepal, speaks to AKSHIT SANGOMLA about glaciers in Nepal and the impact of climate change on them

- AKSHIT SANGOMLA

The glaciers in Nepal are morphologically different from the glaciers elsewhere. How?

Nepal has summer accumulation-type glaciers because the country receives more than 80 per cent of its precipitation during the summer. Another characteristic of the glaciers is that the ice is covered with layers of debris such as soil, sand, rocks, pebbles and even big boulders. If the thickness of the debris is more than 1 m then the melting rate of the ice is slow. If the debris is thin, 2-3 cm, then the rate of melting becomes high. The debris absorb more solar radiation as they are black or brown in colour. The energy budget on the glacier surface would be different with a little debris on the ice. These are the unique characteristics of the Himalayan glaciers in Nepal.

Has the snowfall pattern in the Nepal Himalayas changed recently?

We do not have data on snowfall for the Nepal Himalayas. What we do have is satellite data but it shows the snow cover and not the depth of the snow. We know the snow cover area is decreasing on a decadal scale. In terms of rainfall, no noticeable trend is visible. But variations are visible in terms of temperature rise. The country’s maximum temperature increased by a significant 0.0560C per year between 1971 and 2014. The minimum temperature also increased, but the rate is lower at 0.0020C per year. The rising temperature makes the Nepal Himalayas vulnerable.

In the context of increasing temperatures, another important aspect is the settling of black carbon on the glaciers which increases the rate of melting. Is it impacting glaciers in Nepal?