China is planning a rapid expansion of its weather modification programme to cover an area more than one and a half times the size of India, in a move likely to raise concerns among the country’s neighbours.
The decision, announced by the cabinet on Wednesday night, would increase fivefold the world’s biggest cloud-seeding operation, which already employs an estimated 35,000 people.
For six decades, the communist nation has deployed military aircraft and anti-aircraft guns to lace clouds with silver iodide or liquid nitrogen to thicken water droplets to the point where they fall as snow or rain. The technology has mostly been used at a local level to alleviate droughts or clear skies ahead of major events, such as the 2008 Olympics or last October’s 70th anniversary of the People’s Republic of China.
But the proposed enlargement is on a scale that could affect regional weather patterns. The cabinet said it wanted to extend the artificial rain and snow programme to cover at least 2.1m sq miles (5.5m sq km) of land by 2025. The long-term plan envisages that by 2035, the country’s weather modification capabilities would reach an “advanced” level and focus on revitalising rural regions, restoring ecosystems and minimising losses from natural disasters.
It follows a rapid buildup of capacity in recent years. A 2017 plan earmarked $168m (1.15bn yuan) for four new planes, eight upgraded craft, 897 rocket launchers and 1,856 digital control devices to cover 370,000 miles (960,000 sq km), about 10% of China’s territory.
Part of that is a new weather modification system in the Qinghai-Tibet plateau, Asia’s biggest freshwater reserve. Chinese scientists are working on the ambitious Tianhe (“sky river”) plan to divert water vapour northwards from the Yangtze River basin to the Yellow River basin, where it would become rainfall.
They say they have found potential channels near the boundary of the troposphere that could carry 5bn cubic metres of water annually. The China Aerospace Science and Technology Corporation has reportedly constructed hundreds of chambers in the mountain region – known as Asia’s water tower – to feed silver iodide into the atmosphere in large volumes.
This attempt to hydro-engineer the sky could ease shortages in the dry north of China but may exacerbate problems in south-east Asia and India if it affected the flow of the Mekong,