The melting of the Earth's ice and snow is accelerating the effects of global warming and could trigger wider-ranging impacts on people, economies and wildlife, the United Nations warned in a report on Monday.
"Snow and ice reflect 70% to 80% of the sun's energy, whereas water absorbs it. If snow and ice continue to melt, this will amplify global warming," report author Paal Prestrud told a press conference in the Norwegian Arctic town of Tromsoe.
The Global Outlook for Ice and Snow report was launched on Monday by the United Nations Environment Programme to mark World Environment Day on June 5.
It argued that an estimated 40% of the world's population could be affected by the loss of snow and glaciers on the mountains of Asia. Many Asian rivers begin in the Himalayas and less ice and snow would mean less water for drinking and agriculture.
In addition, rising sea levels would affect low-lying coasts and islands, hitting hard countries such as Bangladesh or Indonesia.
Melting ice and snow are also likely to increase hazards including avalanches and floods from the build-up of potentially unstable glacial lakes.
Rising temperatures and the thawing of permafrost, or frozen land, is triggering the expansion of existing lakes, and the emergence of new lakes and rivers in places like Siberia.
"Snow and ice are continuing to decline because of human activity. They will continue to do so if greenhouse gases continue to be emitted," Prestrud added.