The glacial regions around the highest peak in the world are melting and researchers report  the melt has been happening for decades, with temperatures rising and snowfall declining since the 1990s.

Glaciers in the Mount Everest religion have shrunk by 13 percent in the last 50 years and the snowline has shifted upwards by 180 meters (590 feet) according to the study's lead author, Sudeep Thakuri.

Since the 1960s, small glaciers of less than one square kilometer have been disappearing most rapidly, with a 43 percent surface decline. The receding ice and snow is melting faster than it can be replaced, researchers report, revealing rocks and debris that were previously hidden under thick layers of 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.

Thakuri said that while no concrete connection between glacial retreat and climate change has been established, researchers generally suspect that the decline of snow and ice in the region is the result of human-generated greenhouse gases altering the global climate.

Thakuri and his team conducted their research by compiling satellite imagery and topographic maps and reconstructing the glacial history of Everest and the surrounding 1,148 square kilometer (713 square mile) Sagarmatha National Park. Their statistical analysis shows that the majority of the glaciers in the national park are retreating at an increasing rate, Thakuri said. The researchers state that since 1992 the Everest region has seen annual temperature increases of 0.6 C (1.08F) and annual precipitation decreases of 100 millimeters (3.9 inches) in the pre-monsoon and winter months.  

"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."

The research team will present their findings on May 14 at the Meeting of the Americas in Cancun, Mexico -- a scientific conference organized and co-sponsored by the American Geophysical Union.