Seeds of change: weather control

A remarkable new technology is helping countries around the world produce more rain by manipulating the weather. Vision reports

In 2011, the UAE spearheaded several humanitarian missions to the Horn of Africa to help Ethiopia, Somalia, Kenya, and Uganda combat the worst drought – and resulting famine – the region had experienced in 60 years. At the same time as the UAE was aiding these African nations, it was also dealing with its own challenges, in the grip of a rainless stretch that lasted almost three years.

But instead of crossing its fingers and hoping for storms, the Emirates attempted to do something many people thought occupied the realms of science fiction. They tried to change the weather. It’s hard to say whether the record rains the nation experienced in the spring and summer of 2013 were completely man-made, but it’s likely that much of the precipitation was engineered by cutting-edge meteorology. In the future, instead of sending food aid to its neighbours, the UAE might be able to send something more precious – rain.

Cloud seeding is used to protect crops by preventing the formation of hailstones
Cloud seeding is used to protect crops by preventing the formation of hailstones

The science behind cloud seeding has been around for more than half a century, but scientists are only now unlocking its deepest secrets, taking a practice that was once looked at as a fringe or pseudo-science into the realm of legitimate research, one backed by international standards and strong evidence.

It all began in 1946, when scientists working at General Electric began spreading particles of dry ice and the compound silver iodide into clouds. The idea was that the tiny particles would act as nuclei for rain droplets or snowflakes, causing water to coalesce around them and drop from the clouds, causing precipitation.

Seeding experiments

Cloud seeding is not a panacea for the world’s water woes. It can’t produce rain from a clear sky. Instead, the technology is designed to wring a little extra precipitation from an existing weather event. Experts think that cloud seeding can improve rain or snow by eight to 15 per cent. When combined with hi-tech water management and conservation it can mean the difference between water security and shortage in places that depend on infrequent rainstorms.

One of the most famous modern cloud-seeding projects happened in 2008, when China, preparing for the Beijing Olympics, set up rockets outside the city. The idea was to send the silver iodide bursts into certain clouds and force them to rain themselves out before reaching the Opening Ceremonies and other key events. At other times during the Games, cloud-seeders hoped to cause rain near the capital to settle down the dust and pollution in the city.

Seeding equipment on planes
Seeding equipment on planes

The US has been the epicentre of cloud seeding since the science began. Projects in the state of North Dakota have proven that cloud seeding can help prevent rainstorms from producing hailstones, which can destroy crops. For decades, projects in the Rocky Mountains and Sierras have attempted to help ski areas produce extra snow. But the most important project is taking place now in the state of Wyoming, and the results will be published in late 2014. Using the latest technology, researchers have been monitoring seeding projects in that state’s mountains and are optimistic that once and for all they will find conclusive evidence proving that cloud seeding does work, something that has eluded scientists for decades.

We are trying to reach the best procedure to enhance the amount of rainfall to recharge underground water and increase rain collected in dams ... Compared with the benefits, it is not costly at all

Ali Al Musallam, Head of cloud seeding, National Centre of Meteorology and Seismology

Cloud development

Some of the most exciting water-modification projects are taking place in the UAE. In 2010, the Swiss company Meteo Systems tested its ionising towers in the desert of Abu Dhabi. Fifty 10m tall towers were placed across the desert, which pumped negatively charged ions into the atmosphere when the humidity reached 30 per cent. The ions, Meteo Systems believes, then attach to potential rain nuclei in the atmosphere, helping them stay aloft and last longer than normal. That, the company claims, gives rain clouds a greater chance of developing.

While many world experts question the physics behind ion-generated rain, Abu Dhabi did experience 52 summer rain showers during the test period. But the government of the UAE, while interested in the results of such experiments, has been putting its money behind traditional cloud seeding technology. Though the UAE has dabbled in cloud seeding since 1990, in 2000 the country’s meteorologists began collaborating on a pilot study with scientists from the National Center for Atmospheric Research in Colorado, Nasa and researchers from South Africa.

Cloud-seeding could eventually help to ease the effects of drought
Cloud-seeding could eventually help to ease the effects of drought

The collaboration looked at the best seeding techniques and areas for the UAE to focus on before the National Centre of Meteorology and Seismology took over the programme in 2006. The programme was intensified in 2013, and between April and September, the Centre conducted 124 cloud-seeding runs. While it’s difficult to quantify exactly how much water the project produced, Ali Al Musallam, head of the cloud seeding operations, says he believes it increased rainfall by 15 per cent on turbulent days and 35 per cent in calmer skies.

As the science of cloud seeding advances, the UAE hopes to remain at the forefront, and plans to continue seeding operations whenever possible. “We are trying to reach the best procedure to enhance the amount of rainfall to recharge underground water and increase rain collected in dams,” says Al Musallam. “Compared with the benefits, it is not costly at all.”