Temperatures up, precipitation down in key Asian watersheds
FRISCO — Even at the frozen roof of the world in the mighty Himalaya, global warming is evident.
The snow line in the Mt. Everest region has moved uphill by 180 meters (590 feet). Glaciers in the region are shrinking, some by as much as 13 percent in the past 50 years, and precipitation has declined, according to a team of scientists who will present their findings this week at the Meeting of the Americas in Cancún, Mexico.
Glaciers smaller than one square kilometer are disappearing the fastest and have experienced a 43 percent decrease in surface area since the 1960s, according to Sudeep Thakuri, who is leading the research as part of his PhD graduate studies at the University of Milan in Italy. Based on the detailed measurements of satellite images, the pace of melting speeding up, Thakuri said.
Because the glaciers are melting faster than they are replenished by ice and snow, they are revealing rocks and debris that were previously hidden deep under the ice. These debris-covered sections of the glaciers have increased by about 17 percent since the 1960s, according to Thakuri. The ends of the glaciers have also retreated by an average of 400 meters since 1962, his team found.
The researchers suspect that the decline of snow and ice in the Everest region is from human-generated greenhouse gases altering global climate. However, they have not yet established a firm connection between the mountains’ changes and climate change, Thakuri said.
“The Himalayan glaciers and ice caps are considered a water tower for Asia since they store and supply water downstream during the dry season,” said Thakuri. “Downstream populations are dependent on the melt water for agriculture, drinking, and power production.”
He and his team determined the extent of glacial change on Everest and the surrounding 1,148 square kilometer (713 square mile) Sagarmatha National Park by compiling satellite imagery and topographic maps and reconstructing the glacial history. Their statistical analysis shows that the majority of the glaciers in the national park are retreating at an increasing rate, Thakuri said.
To evaluate the temperature and precipitation patterns in the area, Thakuri and his colleagues have been analyzing hydro-meteorological data from the Nepal Climate Observatory stations and Nepal’s Department of Hydrology and Meteorology. The researchers found that the Everest region has undergone a 0.6 degree Celsius (1.08 degrees Fahrenheit) increase in temperature and 100 millimeter (3.9 inches) decrease in precipitation during the pre-monsoon and winter months since 1992.
In subsequent research, Thakuri plans on exploring the climate-glacier relationship further with the aim of integrating the glaciological, hydrological and climatic data to understand the behavior of the hydrological cycle and future water availability.
The Intergovernmental Panel on Climate Change and the Water Research Institute-Italian National Research Council are funding the research.
Filed under: climate and weather, Environment, global warming Tagged: | climate change, glaciers, global warming, Himalaya, Intergovernmental Panel on Climate Change, Mt Everest, Sagamartha National Park