Nepalese sherpas have warned that an increase in the rate of snow and ice melt on Mount Everest is making traditional climbing dangerous.
According to the BBC sherpas say that the melt, presumably as a result of global warming, has exposed bare rock faces. This makes climbing with traditional gear like crampons and ice axes hazardous.
Studies show temperatures rising faster at Mount Everest, the highest point on earth, with a summit 29,035 ft (8,850 m) above sea level, than in the rest of South Asia.
Sherpas are concerned that future expeditions to the summit might be threatened if the snow and ice continue to melt at the same rate.
As the season to summit Mount Everest comes to an end, sherpas returning to Nepal's capital, Kathmandu, say they have observed an increase in the rate that snow and ice is melting on the mountain.
They say that conditions are becoming more treacherous because climbers now have to negotiate exposed rock faces and avoid being hit by falling boulders that are being dislodged as the ice melts.
The Sherpas said that it will become more difficult to climb the world's highest mountain, and that mountaineers will need to have advanced technical skills before attempting it.
A US-based scientific survey has installed a number of photographic cameras in the Everest region, taking a photograph every 30 minutes, to record the rate of melting ice and snow.