If you’re throwing a party in your backyard, you probably wouldn’t want rain or other yucky weather to mess with your plans. But if it happens, there’s not much we can do about it. But that’s not necessarily the case for China, which recently used cloud seeding technology to make sure they don’t have to deal with rain and air pollution ahead of a big political celebration earlier this year.

For China, interest to control the weather has quickly escalated over the years, mainly to protect farming areas and have clear skies for big political events. This was the case in the 2008 Beijing Olympics, for example, when the government used cloud seeding to ensure good weather for good events, and has apparently become more and more common in recent years. From 2012 to 2017, China spent over $1.3 billion on weather modification programs. 

Cloud seeding has been around for many years, at least as a concept. It works like this: you inject small amounts of silver iodide into clouds that have a lot of moisture, which condenses around the new particles, become heavier, and eventually fall as rain. A study from 2019 was the first one to definitively confirm that this actually works. After this, there are no more rain-forming clouds around, and you’re guaranteed to have clear weather for some time.

THe other benefit is in terms of air pollution. Beijing, China’s capital, is well known around the world for its high levels of air pollution – caused by the burning of coal to produce electricity and vehicle emissions. In 2019, China was classed as the 11th dirtiest country in the world. But on its 100-year celebration, the Chinese Communist Party would have none of it.

A clear-skied party

The Chinese Communist Party celebrated its centenary on July 1^st, with thousands of people gathering at Tiananmen Square. It was a lovely day, but this wasn’t just good fortune. According to a paper from Tsinghua University, first reported by the South China Morning Post, the government used cloud seeding hours to ensure clear skies. 

The celebration in Beijing was due to be a rocky one, as the city faced an increased in air pollutants and an overcast sky back in July, the researchers reported. It was one of the wettest summers on record. Factories had been closed down days ahead of the celebration to prevent high air pollution levels but this apparently wasn’t enough.

In the paper, environmental science researchers Wang Can says a two-hour cloud-seeking operation was carried out before the celebration, with residents seeing rockets launched into the sky on June 30^th – carrying silver iodine. The artificial rain was successful, as the level of PM2.5 pollutants was reduced by almost two-thirds.

For the researchers, the drop in pollution was directly related to the artificial rain as this was the single disruptive weather event in that period. According to the China Morning Post, it rained almost every day in the week before the ceremony. And on the day it happened, the participants were given raincoats as part of a souvenir pack. 

Last year, China unveiled a plan to expand its experimental weather modification program to cover an area 1.5 times the total size of India. According to a government statement, China will have a fully functional weather modification system in place by 2025 thanks to new research and technologies and improvements in risk prevention.