A group of scientists are proposing cloud seeding on a massive scale on the Tibetan plateau to create more rain to flow into rivers in China’s arid north.
Other researchers, however, have cast doubts on the project saying it is likely to be doomed to failure.
Intensive cloud seeding in the skies above Tibet and the neighbouring region could create more than five billion cubic metres of water a year in rain to flow ultimately into the Yellow River, according to a feasibility study funded by the Qinghai provincial government. That would amount to nearly twice Beijing’s annual water consumption.
Wang Guangqian, the president of Qinghai University who heads the research project, was quoted as saying by the state-run news agency Xinhua: “Between the boundary layer and troposphere in the atmosphere exists a stable, orderly channel for water vapour transportation called ‘Sky River’,”
Planes and rockets would be used to intercept the passing vapour and seed it with chemicals to create rain, the report said.
China started diverting water from the Yangtze River in the wetter south of China to Beijing and other drier areas in the north two years ago.
The Qinghai scientists likened the “Sky River” project as the atmospheric counterpart to the water diversion project.
The Qinghai provincial government was quoted as saying that said would build large ground facilities at Sanjiangyuan and the Qilian and Kunlun mountains to help carry out the cloud seeding.
Wei Jiahua, a professor of hydrology at Qinghai University and a member of the project, said their first step was to launch a satellite to monitor the vapour flow in the atmosphere and chart water resources in the Tibetan region, Xinhua reported.
The data collected by the satellite would guide the launch of rockets in “medium and long range artificial rain implementation plans”, Wei said.
Other scientists, however, have expressed doubts about the plans.
Professor Luo Yong, a meteorologist at Tsinghua University in Beijing who has studied large-scale climate systems, said that if a “Sky River” existed above the Tibetan plateau it had not been mentioned in any textbooks.
Water vapour transportation changed and fluctuated constantly in the atmosphere and it was difficult to predict when and where it would occur, he said.
Luo also doubted if it were possible to carry out cloud seeding on such a scale as previous weather intervention efforts carried out in China have been limited to a small region over short timescales, such as ahead of the Apec meeting in Beijing two years ago.
Fang Hao, a researcher at the Beijing Municipal Research Institute of Environmental Protection who has studied artificial weather manipulation, said the Qinghai project team might not even understand how rain is formed.
Rainfall does not come out of blue, said Fang. It needed many specific conditions, such as the meeting of cold, dry and warm, humid air, which could not be created by human efforts.
Cloud seeding would only work under certain favourable conditions and in most cases it could not increase natural rainfall by more than 10 per cent, Fang said.
A rocket could also only spray could seeding chemicals to induce rain in an area up to a few square metres at an altitude of between 3,000 to 5,000 metres, he added. To create massive rainfall over a large region throughout the year would require so many rockets or planes, the cost would go beyond imagination, he said.
“In short, it won’t happen,” Fang said.
Han Jianhua, the Deputy Governor of Qinghai, said the Sky River project ranked top in the province’s five-year plan, Xinhua reported.
Initial funding for the purchase of cloud seeding planes and other hardware had already been approved, he was quoted as saying.
An official at China Meteorological Administration in charge of artificial weather intervention said the Sky River project had no input from the central government.
“It’s just the idea of Qinghai province,” he said.
The research team at Qinghai University could not be reached for comment.