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The Wild Idea to End Droughts by Triggering Artificial Rain

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Illustration photo by Thomas Levinson / The Daily Beast / Getty

Illustration photo by Thomas Levinson / The Daily Beast / Getty

China is known to have one of the worst air pollution in the world. Images of dense, miasmic smog engulfing its most polluted cities are commonplace. The country has made significant progress in tackling air pollution, but it remains a problem in many areas.

In light of these pollution concerns, it was reported earlier this month by the South China Morning Post that the Chinese government used a weather modification technique called cloud seeding to remove air pollution over Beijing before the country’s Communist Party celebrated its centenary in July. The technique involves using an aerial vehicle such as an airplane or drone to deploy a compound in clouds (most often silver iodide) to trigger the condensation of water in the air. This leads to rain or snow, which inevitably helps to rid the atmosphere of nasty pollution particles.

The artificial rain, Chinese researchers later learned, has actually reduced air pollution over the city by more than two-thirds and raised the air quality index from moderate to good. For the crowd watching the military flyby and the 100-gun salute in Tiananmen Square, the sky was a little better than it had been for a while.

The cloud-seeding might seem completely weird at first glance, but it’s far from science fiction and its star is only on the rise. China previously used cloud seeding during the 2008 Beijing Olympics to reduce smog. Manipulate the weather like Storm’s X Men actually has some utility in addressing some of the current climate problems.

But Katja Friedrich, associate professor of atmospheric and ocean sciences at the University of Colorado at Boulder, told the Daily Beast that using it to eliminate pollution isn’t necessarily the most effective plan, and China could be wrong. believing it to be a reliable tool. Long term solution.

β€œRain eliminates air pollution. There’s no question about it, ”Friedrich said. “But I think it’s easier to solve the problem of air pollution than to try to solve it after the fact with cloud seeding.”

In fact, the most impactful applications of cloud seeding are less pollution than drought. The American West is facing a historic drought, many western states like Arizona, California, Colorado and Wyoming have adopted cloud seeding as a way to hopefully keep crops alive and maintain the water supply. The United Arab Emirates launched a fleet of cloud seeding drones last summer to help Dubai residents beat the heat. China recently announced plans to develop a massive cloud seeding system over the next decade to produce artificial precipitation over 224,000 square miles across the country.

Triggering precipitation could also be important in meeting our energy needs in the future. The utility company Idaho Power has a cloud seeding program that is meant to keep its hydroelectric plants running. This program began in 2003, and the company says it produced almost half a million acre-feet of additional water in the region by 2020.

Studies have shown that cloud seeding can increase precipitation by 5 to 15 percent. Friedrich cautions, however, that this can vary wildly, and we still don’t have a good idea of ​​what interference with condensation and precipitation in the atmosphere will actually lead to.

β€œOnce you handle the cloud, you don’t really know what that cloud would have produced in terms of precipitation without the manipulation,” Friedrich said. β€œIt’s really important to run models where you can maybe simulate the impact of these different technologies. “

There are many books and films that suggest that our attempts to control the weather will simply backfire and usher in a global apocalyptic nightmare: the skies have turned dark, the crops are dead, and humanity is fighting to stay alive. life.

But cloud seeding isn’t as extreme or new as many other ambitious geoengineering proposals, and that means scientists have a better understanding of how it works. Cloud seeding was actually first attempted by an American chemist and meteorologist named Vincent J. Schaefer in 1946. He flew a plane over Massachusetts and released pellets of dry ice into them. clouds, and he was able to help produce snow.

β€œSince ancient times, man has dreamed of manipulating time to his advantage,” Schaefer wrote in 1968. β€œHis efforts to this end have ranged from drawing pictograms, lighting ceremonial fires, participating in dance dances. rain and then over the last twenty-one years directing his attention to using certain scientific relationships to initiate physical and chemical reactions in the atmosphere. ” Seemingly overnight, Schaefer had accomplished what was once impossible for millennia.

The science behind cloud seeding is deceptively simple. Rain occurs when too much water vapor in the air condenses. The clouds get too heavy to hold together, and the water falls back to the ground as liquid droplets. Water vapor condenses around tiny particles in the air, so cloud seeding is about introducing more particles into the clouds to induce more precipitation.

A new cloud seeding idea, first proposed by researchers at the University of Reading in 2017, involves electrifying water droplets in clouds. A positive or negative charge can fuse with other droplets, and heavier droplets are more likely to fall. The United Arab Emirates pioneered the technique with their own cloud seeding projects, and the country’s own weather program says it works.

All of these programs are being taken more seriously as the science and technology behind cloud seeding is getting more sophisticated every year. Armin Sorooshian, professor of chemical and environmental engineering at the University of Arizona, told the Daily Beast that big data and machine learning are being used to better understand how to make clouds produce rain. Getting a better idea of ​​the size of the particles and droplets distributed in the air and how they influence cloud formation could give scientists more clues on how to prepare for cloud seeding. to achieve specific goals.

This type of research can also help scientists better understand climate change, Sorooshian said. We still don’t know much about how particles created by human activity affect clouds.

“I’m currently leading this huge NASA mission called ACTIVATE, and the goal of this $ 30 million project is just to understand the science of aerosol-cloud interactions, because it’s believed to be the biggest uncertainty. in our understanding of how the climate is changing, ”Sorooshian said. “It has to do with these interactions between particles and clouds.”

There are, of course, risks in manipulating the weather – the books and movies that contemplate these calamities are right. We have to be careful about how much cloud seeding we do, Sorooshian said. If you deploy a compound like silver iodide in the air, there is concern that it could fall from the sky and change the pH levels of a body of water, for example, which could have an impact. impact on the health and stability of the plants and animals below.

β€œI’m not quite sure if I am arguing for people to start doing this aggressively right now,” Sorooshian said. β€œWe need to learn more. “

As droughts become more frequent due to climate change, cloud seeding is emerging as a more regularly used tool to help alleviate water shortages. But it must be seen as a tool within an arsenal of solutions. If there are no clouds in the sky, cloud seeding will lead to bupkis. Groups that rely heavily on cloud seeding, like the Chinese government, would do well to keep this in mind.

β€œIf you are going to alleviate the drought, you have to have a more ambitious plan,” Friedrich said. “Not just the cloud seeding.”

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