By Charles Haviland
BBC News, Kathmandu
A young Sherpa climber from Nepal has said he will undertake an expedition up Mount Everest to draw attention to the risks posed by climate change.
Scientists say many Himalayan glaciers are melting
Dawa Steven Sherpa, who is half Nepalese and half Belgian, is only 23 but has already climbed Everest and another of the world's highest peaks.
He said he was inspired after seeing the melting of ice on the mountain.
Mr Dawa will use his new trip to highlight global warming, which he believes caused this event.
He said he decided to launch this trip after a frightening experience on the mountain's Khumbu icefall during a climb last year.
"As I was going up, a big group of my Sherpa team were coming back down with their loads. They were petrified - with reason, because the ice below our feet was creaking and the ice had all melted into slush," Mr Dawa recounted.
"And one of the Sherpas turned and said to me, Dawa, if you want to die today, continue climbing. But listen to us and come back down. And that exact same day, from that exact point, the entire ice field had collapsed."
Mr Dawa believes global warming caused the event.
Scientists say global warming is melting hundreds of Himalayan glaciers from Pakistan to Bhutan, some of which create lakes which are in danger of bursting through their natural barriers and flooding the valleys.
The Nepal-based International Centre for Integrated Mountain Development, one of the sponsors, predicts that by 2050 all such glaciers will have melted, so the floods will be followed by drought.
It says a fifth of humanity is sustained by the Himalayas' river systems.
Mr Dawa's expedition will also instigate a clean-up of Everest and a fund for community development in the region.
It will hope to inspire the building of early warning systems to protect people from lake outbursts.