Himalayan Glaciers

There has been an almost worldwide recession of glaciers since the last ice age, including within the HimalayasThe Hindu Kush-Himalayan (HKH) region extends 3500 km across eight countries from central Afghanistan in the west to Myanmar in the east (Figure 1). This region contains the largest amount of ice outside the polar regions and feeds the major South Asian river basins, including the Ganges, Indus, and Brahmaputra. There are over 54,000 glaciers in the HKH region which are highly vulnerable to global climate change, experiencing significant warming (0.21 ± 0.08 ◦ C/decade) over the past few decades.

Screen Shot 2017-05-13 at 10.42.52 AM

Figure 1. The Hindu Kush-Himalayan region

Glaciers act as natural hydrological buffers, releasing melt water during summer and early autumn in particular. They  are natural reservoirs storing water as ice instead of using a dam. Millions of people depend on the waters from the rivers fed by snow and glacial melt for domestic use, agriculture, hydropower and industry. As the glaciers shrink so does the melting and consequent runoff they provide.

HKH Mass balance

Figure 2. Mass loss from the Asiatic High Mountains compared to other regions. (Dyurgerov and Meier, 2005)

Most Himalayan glaciers have both retreated and lost mass since the mid-19th century as shown by cumulative mass balance (Figure 2) as well as changes in length. Between 2003 and 2009, Himalayan glaciers lost an estimated 174 gigatonnes of water, equivalent to almost half of the River Ganges’ annual runoff volume. Substantial glacial mass and area losses are projected in the coming decades for most parts of the HKH based on climate models and glacio-hydrological projections. Warmer temperatures will also cause more precipitation to fall as rain than snow, resulting in melting ice not being replenished.

WestRongbuk

Figure 3a. West Rongbuk Glacier, 1921 (Image. GlacierWorks)

WestRongbuk2009

Figure 3b. West Rongbuk Glacier, 2009 (Image. David Breashears)

Hydro-meteorological stations are limited in the Himalayan region. With increased interest in the future of Himalayan glaciers, regional South Asian countries as well as international institutions are collaborating for further field expeditions to install automated weather stations and gather additional data. Read more on field work done in the Himalayas.


Snow and Ice Research in the Himalayas – Video Courtesy Susan Hale Thomas

References

Bolch T, Kulkarni A, Kääb A, Huggel C, Paul F, Cogley J, Frey H, Kargel J, Fujita K, Scheel M. 2012. The state and fate of Himalayan glaciers. Science 336: 310–314, doi: 10.1126/science.1215828.

Dyurgerov, M.B. and Meier, M.F., 2005. Glaciers and the changing Earth system: a 2004 snapshot (Vol. 58). Boulder: Institute of Arctic and Alpine Research, University of Colorado

Shrestha, A.B., Agrawal, N.K., Alfthan, B., Bajracharya, S.R., Maréchal, J. and Oort, B.V., 2015. The Himalayan Climate and Water Atlas: impact of climate change on water resources in five of Asia’s major river basins. The Himalayan Climate and Water Atlas: impact of climate change on water resources in five of Asia’s major river basins.