Decoding Himalayan glaciers through tree rings

For the first time in the country, a team of nine scientists from the Birbal Sahni Institute of Palaeosciences ( BSIP) in Lucknow has used the tree ring data to study the health and behaviour of Himalayan glaciers over a period of four centuries.

The findings have reiterated the visible shrink in the glaciers’ size and shed light on the correlation between their melting and the heat in sun rays and oceanic currents, apart from global warming. The study was recently been published in the prestigious international journal, Scientific Reports, of Nature group.

The scientists have used tree ring data of around 400 years from Himalayan conifers in the glaciated valleys of Uttarakhand, Himachal Pradesh and Kashmir for research.

“Glacier melting has been an area of great concern, as glaciers are huge water reservoirs and a source of fresh water. Our study highlights the loss in volume of the Himalayan glaciers and shows that even when European glaciers were expanding, Himalayan glaciers were shrinking,” said senior scientist Parminder S. Ranhotra.

Lead author of the research team, Dr Mayank Shekhar, said the team conducted research on 13 glaciers. Three of these were in Jammu & Kashmir, six in Himachal Pradesh and four in Uttarakhand.

The research showed that every 10 years, Uttarakhand and Himachal Pradesh glaciers were melting at a rate of 6 per cent and 5 per cent, respectively, while glaciers of Jammu & Kashmir were stable.

Dr Ranhotra said that there is no instrument to measure glacier health over such a long period of time and the team used tree rings. BSIP is the first institute in the country to use this technology.

These rings reflect details of climatic change during a year. Without cutting the tree, scientists draw out a section of an old tree to study the rings.

If the width of the ring is thick, it reflects favourable climatic conditions and if the ring is thin, it indicates the tree was under stress in that particular year. The rings reflect the changing behaviour of glaciers due to rain and temperature.