The Guardian (London) - Final Edition
April 19, 2007 Thursday
China claims to have created first artificial snowfall
Ian Sample, Science correspondent
Chinese weather experts claim to have triggered the first artificial snow showers by releasing tiny particles into clouds over the Tibetan plateau.
The experiment was hailed as a success for the drought-stricken region, where freshwater lakes are drying up as warmer temperatures force thousands of glaciers into rapid retreat.
A spokesman for the Tibet meteorological office said artificial snowfall was created by seeding the clouds with particles of silver iodide. The fine particles encourage the formation of ice crystals in the clouds, which grow until they fall as snowflakes.
The state news agency, Xinhau, said the snow reached a depth of 1cm and accumulated on the Qinghai-Tibetan plateau, which feeds the Yangtze river. The experiment proves it is "possible to change the weather through human efforts on the world's highest plateau", Yu Zhongshui, an engineer with the Tibet meteorological office, told Xinhau. "To launch artificial precipitation can help alleviate drought on the grassland in northern Tibet."
Last year UN researchers reported that tens of thousands of glaciers in Tibet were melting rapidly and in danger of disappearing within 100 years because of global warming. Rising temperatures on the world's highest plateau have speeded up the shrinkage of more than 80% of the glaciers. Although the melting glaciers have released more water into rivers such as the Yangtze, dry regions in the north are facing severe water shortages.
Many weather experts doubt the effectiveness of cloud seeding, in part because it is impossible to prove a cloud would not have shed snow or rain without being seeded.
The technique is common in China, where officials have used it to trigger downpours before public holidays to clear the skies of pollution. China plans to use it before the 2008 Olympics.