Over 70% of glacier volume in Everest region could be lost by 2100

Instruments used to study the Mera Glacier region of the Dudh Kosi basin (Credit: Patrick Wagnon)
Instruments used to study the Mera Glacier region of the Dudh Kosi basin (Credit: Patrick Wagnon)

A team of researchers from Nepal, France and the Netherlands have found that Everest glaciers could be very sensitive to future warming, and that sustained ice loss through the 21st century is likely. The study which was published in the journal, The Cryosphere, claims to be “the first detailed modelling study of all glaciers in the Dudh Koshi basin in the Everest region of Nepal”.

Dudh Koshi Basin, Nepal Himalaya (Google Earth).
Dudh Koshi Basin, Nepal Himalaya (Google Earth).

The idea behind the study was to develop and test a model that could examine the sensitivity of glaciers in the Everest region to both past and future climate changes. The team studied glaciers in the Dudh Kosi basin in the Nepal Himalaya, which is home to some of the world’s highest mountain peaks, including Mt Everest, and to over 400 square kilometres of glacier area. The glaciers in the High Mountain Asia region that includes the Himalayas, contain the largest volume of ice outside the polar regions. “Apart from the significance of the region, glaciers in the Dudh Kosi basin contribute meltwater to the Kosi River, and glacier changes will affect river flows downstream,” says Joseph Shea of the International Centre for Integrated Mountain Development in Kathmandu, Nepal.

Glaciers gain mass by snow accumulation and lose mass by melting (ablation). Depending on what occurs more, the glacier either gains or losses mass.The glacier model used by Shea and his team shows that the glacier volume could be reduced between  70 and 99% by 2100. The rate at which this occurs will depend on how much greenhouse-gas emissions continue to rise, and on how this will affect temperature, snowfall and rainfall in the area.

To find out how glaciers in the region will evolve in the future, the team started by using field observations and data from local weather stations to calibrate and test a model of glacier change over the past 50 years. “To examine the sensitivity of modelled glaciers to future climate change, we then applied eight temperature and precipitation scenarios to the historical temperature and precipitation data and tracked how glacier areas and volumes responded,” says study co-author Walter Immerzeel of Utrecht University in the Netherlands.

The results were clear- glaciers in the Everest region could see sustained mass las through the 21st century and based on the model, glaciers would be highly sensitive to temperature increases between +6 and +8°C by the end of the century.

The researchers however, caution that the results published should be seen as a first approximation of how the Himalayan glaciers will react to increasing temperatures in the future. Says Patrick Wagnon, a glaciologist- “Our estimates need to be taken very cautiously, as considerable uncertainties remain.” For example, the model simplifies glacier movements, which impact how glaciers respond to increases in temperature and precipitation.”

 For more information please access the original paper here:  The Cryosphere