UK-based campaign group Friends of the Earth said melting glaciers had swollen Himalayan lakes and could create floods that would risk lives and damage a unique environment.

The group will deliver a petition to the U.N.'s World Heritage Committee in Paris on Thursday, together with Everest climbers such as Reinhold Messner, asking for the world's highest mountain to get monitoring and assessment of the risks.

"Mount Everest is a powerful symbol of the natural world, not just in Nepal -- if this mountain is threatened by climate change, then we know the situation is deadly serious," said Prakash Sharma, director of Friends of the Earth Nepal.

Global warming, from increased emissions of gases such as carbon dioxide, threatens violent weather conditions across the globe, scientists say. Glaciers are among the first to show signs of climate change, environmentalists say.

"In 1953 snow and ice reached all the way to base camp, but now it ends five miles above," said Pemba Dorje Sherpa, who climbed the mountain in the fastest time of just over eight hours in May.

"Everest is losing its natural beauty," he said in a statement. "Our communities rely on tourism. If we lose this, there will be nothing left for our children."

Campaigners are also asking for corals reefs in Belize and glaciers in Peru to be added to the U.N.'s danger list.