Around the world governments are using cloud seeding to try to influence where and when it rains. If they succeed they may help alleviate droughts. But they also risk sparking political tension. Could nations find themselves fighting over who owns the clouds above us?
Nik Mir, Investment Director, Rathbones
Water covers 70% of the planet’s surface, but a forecast leap in demand, combined with increasingly aggressive weather patterns, means a growing number of countries are looking to create rain on demand.
The process of cloud seeding has been around since the 1940s, but its popularity has rapidly increased in the past few years. According to the most recent report by the World Meteorological Organisation, the number of countries with official cloud-seeding operations jumped from 42 in 2011 to 60 last year.
The idea might seem uncontroversial — surely if a drought-hit region needs rain then triggering it makes sense?
But many view controlling the weather as extremely contentious, partly because of questions about its reliability and the fear that conflicts could erupt if a country feels its neighbour is “stealing” its rainfall.
Rain falls when supercooled droplets of water in clouds form around particles, like dust or salt, to create ice crystals. Too heavy to remain suspended, they fall, melting on their way to earth. By using aircraft to disperse materials such as silver iodide, magnesium, sodium chloride and potassium chloride it is possible to trigger this process.
The method was discovered in 1946 by Dr Vincent Schaefer, who in his obituary was hailed as “the first person to actually do something about the weather and not just talk about it”.
Dr Schaefer’s motives all those decades ago in his New Hampshire observatory may have been purely scientific, but subsequent applications have been at times nefarious.
It is alleged the US used cloud seeding during the Vietnam War to prolong the monsoon over the Ho Chi Minh Trail. Operation Popeye, as it was known, was an attempt to hinder the movement of North Vietnamese troops and equipment as well as suppress anti-aircraft fire.
Russian pilots have alleged Moscow engaged in cloud seeding above Ukraine and Belarus after the Chernobyl nuclear disaster in 1986 to try to ensure that radioactive particles in the clouds did not make it towards densely populated cities, such as the Russian capital.
Meddling with the weather may also have unexpected consequences. America attempted in 1947 to weaken a hurricane with 102kg of dry ice, only for it to change direction and hit land with devastating consequences. The General Electric corporation was sued for damages as a result.
In spite of this cautionary tale, the global community is unlikely to abandon cloud seeding and the potential benefits it could bestow.
Forecast for rain
One country at the vanguard of attempts to influence the weather is the United Arab Emirates, whose government recently launched the £3.8 million Research Programme for Rain Enhancement Science.
The nation, one of the driest on earth, receives roughly 120mm of rain per year compared to the UK’s average of 885mm. The UAE embarked on 242 cloud-seeding operations in 2017.
China also has ambitious plans. It famously used cloud seeding to ensure the opening ceremony of its 2008 Olympics remained a dry affair and is experimenting with a system of burners on ridges in the Tibetan Himalayas that fire silver iodide particles into the air to try to increase rain and snowfall. China is thought to be aiming to generate 10 billion cubic metres of rainfall in an area the size of Iran to feed the Yangtze and Yellow rivers.
While the theory behind the process is widely regarded as sound, remarkably — in the light of how many countries are attempting it — cloud seeding had until recently only been “proven” in laboratory conditions.
This year an American study in Idaho broke new ground when it published for the first time data gathered outside a lab that showed cloud seeding working.
Researchers used the latest radar equipment to identify the formation of water particles where cloud-seeding aircraft had flown and monitored them as they grew into snowflakes.
The Wyoming Weather Modification Pilot Programme, the largest study monitoring silver iodide cloud seeding, found in 2016 that the technique can increase precipitation if conditions are just right but cannot be relied upon over a long period or on a large scale.
Cloud seeding’s disciples are unlikely to be perturbed by questions about its efficacy, though, raising the question of whether some form of monitoring system is needed given the regional frictions it can create.
The UN’s Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques, which forbids weather tampering from being used as a tool of war, was established in 1977. In 2010 the UK’s Science and Technology Committee stated that the line between peaceful and hostile usage of cloud seeding was “very thin”.
Indeed, political discontent has already been created by cloud seeding. Iran’s former president, Mahmoud Ahmadinejad, claimed in 2011 that Europe was “stealing its rain” through seeding programmes and cited this as a key cause of droughts in his country. The Chinese cities of Zhoukou and Pingdingshan also had a public spat over the latter’s programme.
Forecasts for more extreme droughts will only fuel the desire of nations to control the weather for their own gain — and to develop the science behind it. But playing with clouds might bring more than just rainstorms.