Talking to TOI, the duo, who were on a visit to Kolkata to deliver a talk on mountaineering and climate change, said that rising vehicular pollution and emissions from thermal power plants, brick kilns and factories in north and eastern India are to blame for this dangerous phenomenon. "The soot particles are funneled by winds to the higher reaches of the Himalayas from the north Indian plains and deposited on the snow. As a result, heat from the sun's rays is absorbed by these particles, causing the snow to melt and form lakes. Many of these lakes are held by fragile moraine (glacial debris) which, in the event of an earthquake, will give way and cause the lakes to burst," explained Dixit, who is also the chief editor of Nepali Times that devotes a lot of space to environmental issues. He added that with rising affluence in India, vehicular and industrial emissions will also rise, thus causing more soot particles to get deposited in the Himalayas and expediting the process of the snow melting and forming more unstable lakes.

Many of these lakes, said Sherpa, are huge and hold enormous volumes of water. The Tso Rolpa, which lies northeast of Kathmandu, is for instance 2km long, a kilometer wide and more than 75m deep. Lake 464 near Baruntse Mountain in eastern Nepal is also as large and very unstable. If these lakes burst due to an earthquake, the Glacial Lake Outburst Flood would be devastating not only for Nepal, but also for India. Dixit said the danger of 'Himalayan tsunamis' hitting the Indian plains is real and present, and increasing by the day.

Sherpa, who started climbing in 2003 and summitted Ama Dablam — one of the most technically difficult mountains to climb — that very year, said the face of the higher reaches of the Himalayas is changing very rapidly. "Every time we revisit a mountain, we see the stark difference. Even on the summit ridge of the Everest (which she summitted in 2006 and 2007), there is less snow now. Camp 3 on the way to Everest was totally snow-clad even a few years ago, now it is all rock and boulders. More icefall is happening now and the whole Himalayan range, especially the eastern Himalayas, is thawing, and that's very dangerous," she said.

On Saturday evening, Maya and Dixit spoke on climbing and climate change at a lecture organized by the Kolkata section of The Himalayan Club in collaboration with the Consulate General of Nepal in Kolkata. The lecture, titled 'Lure Of The Mountains', also featured veteran climber and former president of The Himalayan Club Meher H Mehta and mountain lover Bhanu Banerjee who accompanied Sir Edmund Hillary on an expedition to the Himalayas in 1961. Nepal's consul general, Chandra K Ghimire, also spoke at the event.