Water Works

Cloud Seeding in the Age of Drought

by stuart lombard

In February of 2009, a portion of Northern China was experiencing their longest drought in 38 years. After four months, it finally snowed so hard that 12 major roads around Beijing were closed. The snow happened to be, to a certain extent, artificial. Over the course of three days, over 300 sticks of silver iodide (I-Ag) were fired into the clouds to cause them to quickly produce more ice crystals and promote increased precipitation. It is unknown if the silver iodide actually caused the snow, or if it merely caused heavier snow.

When California Governor Edmund Brown declared a state of emergency on January 17, 2014, it was a call for all Californians to conserve as much water as possible. On the day of the signing he said: ‘We can’t make it rain, but we can be better prepared for the terrible consequences that California’s drought now threatens, including dramatically less water for our farms and communities and increased fires in both urban and rural areas.’ And the drought continued to worsen throughout the 2014 and 2015. In March of 2016, rain arrived in California and when scientists saw the clouds, they decided to shoot silver iodide into them. While the rain would have still fallen, it is estimated that the use of silver iodide caused there to be about a 15% increase in the amount of precipitation.

In the immediate aftermath of the 1986 Chernobyl disaster, clouds of radioactive fallout were moving quickly towards some of Russia’s biggest cities including the capital: Moscow. With the lives of millions at risk from high exposure to radiation, the Russian government, in order to protect their citizens, seeded the clouds of fallout with silver iodide, and caused the fallout to never reach the capital. In the process, approximately 4000sq/mi of Belarus was contaminated with the radioactive fallout instead.

In these events, the technique used is called cloud seeding. Developed in the 1940’s, the initial theory can be credited to Vincent Schaefer who figured out how to stimulate the growth of ice crystals using a curious new contraption that evolved into the modern freezer. He discovered that when he put dry ice into the cold box, ice crystals formed within the fog. He later became the first person, in conjunction with his boss Dr Irving Langmuir, to ‘seed’ a cloud. By flying over a four-mile long cloud and dispensing dry ice over it, he was able to make the cloud produce snow as a result.

The discovery of silver iodide was made by the junior team member: Dr Bernard Vonnegut, brother of author Kurt Vonnegut and in his first year working at GE. He discovered that silver iodide best mimicked the atomic structure of ice crystals, and by creating a smoke of silver iodide, he was able to cause the supercooled water particles to quickly form ice particles by linking to the silver iodide. Silver iodide turned out to be very effective at seeding clouds and remains to be the most popular method.

While the seeding of clouds has been demonstrated many times, scientists are still uncertain to how much it works. In California, the use of silver iodide to seed the clouds was estimated to have produced a 15% increase in precipitation, but there are also accounts of cloud seeding failing to reduce the amount of precipitation that fell on important events, and when precipitation does occur, it is oftentimes difficult to discern whether the precipitation would have still occurred, or if it was as a result of cloud seeding.

The first two instances of cloud seeding discussed were both as means of ending droughts, and that is still one of the main uses of cloud seeding today, the other being to keep rain away from big events such as Summits or the Olympics. Drought is an increasing problem, and as the global temperature rises, we are going to be experiencing more droughts and longer droughts.

There are three kinds of droughts: meteorological, hydrological, and agricultural. The first refers to a drought brought on by lack of precipitation; the second is when we start to lose soil moisture and groundwater; and the third is when our crops cannot get enough water to survive. The first often leads to the second, and the second to the third. What we have been seeing in California lately is that when precipitation fails to fall in adequate supplies, the ground dries, and the crops suffer. But farmers need to keep their crops alive or else they will not make money, so they turn to extracting water from deep underground. And as the drought has continued, and Californian farmers continue to plant thirsty crops, they are never satisfied with the amount of water. Currently, they are in danger of depleting their underground water reserves, but they just keep drilling. The consequences of this is that in the process of extracting this water, they are also destabilising the earth, and the area surrounding wells has been found to be sinking, causing some roads to crack.

So, if California never seems to have enough water, and they will eventually run out of the deep reserves, why not use cloud seeding? With the rise in temperatures, the melting of the polar ice caps, and rise in sea levels, we will be seeing less snow, and more frequent rain. The increased temperatures will cause the water cycle to speed up, which means that while rain will be more frequent, it will also be evaporating faster. The problem with this is that it does not always rain in the same place, which is how we get meteorological droughts: too much time in between rainfall. And if we add that to the increased evaporation of water which is a side-effect of increased temperatures, then agricultural droughts will become more prevalent.

Besides being terrible in and of itself, agricultural droughts have the greatest negative impact upon the economy. California produces approximately two-thirds of the nation’s fruits and nuts: among these are almonds, which in 2015 garnered 5.33 billion dollars in revenue, second only to milk and cream. Almonds are delicious, healthy, and they have been massively growing in popularity in the past few years. The negative aspect of almonds is that they need a lot of water to grow. The popularity of almonds has driven farmers to prioritise their growth over less popular, but more water efficient, leafy greens. And this brings us back to the aquifer depletion, ground sinking, and especially drought. The lack of sufficient amounts of precipitation has not stopped the farmers from growing particularly thirsty crops, such as almonds, that will make them more money. And that great motivator has caused them to go to extraordinarily damaging lengths to get more water.

Aquifers can take many years, even decades, to replenish. But that is only if they are given the time to replenish. California’s aquifers will be fully drained, and they will not be given the time they need in order to be replenished. Additionally, the sinking of earth around wells in California means that the depleted reserves of freshwater are collapsing on themselves, making it difficult to replenish properly without becoming contaminated by toxins that may be getting dislodged. At some point in the relatively near future, farmers are going to realise what they have done, that there are no more rich reserves of freshwater. At that point, they will realise that their main source of water will be at the mercy of clouds, which may not end up giving enough precipitation to Californian crops to keep them alive. It does not take a visionary to see that when there is a dearth of water, and too much demand for almonds, that the price will increase dramatically as almond trees die from lack of proper nutrition. With price increases, almonds and other nuts and fruits will become just short of luxury commodities. Farmers will then realise that their business is not sustainable, and that drought conditions are far from ideal for their crops. With the unpredictability of weather, that leaves a great solution if we want to keep munching on dark chocolate covered almonds: cloud seeding, a way of ensuring that farmers are getting the water they need to sustain their crops.

But what happens when California starts using their considerable wealth to control the weather to act for their advantage? Who will be confronted with a lack of rainfall because California is causing it to fall over their crops? It will turn into a cycle of drought, and those who live in rural, non-farming communities will likely feel the brunt of the super-droughts that are too close for comfort. This is a question for ethics, but it will likely be answered by the economy. The economy likes almonds because they can produce a lot of revenue. But the ethical dilemma will be the one that sparks the greatest conflict. Should one state be allowed to use cloud seeding if it means that another state is deprived of the rain that they would have gotten otherwise? We have already seen in Maharastra, India’s wealthiest state and second wealthiest sub-state worldwide, the large-scale use of cloud seeding to save their agriculture sector from suffering. Over half of the state is dominated by agriculture which produces rice, cotton, and sugarcane among other fruits and vegetables. The state’s wealth means that they have been able to develop an efficient method of cloud seeding, with a central tower scanning nearby clouds to assess their potential for precipitation before calling planes to seed the most viable clouds. It is unknown how much of an impact Maharastra’s cloud seeding efforts have had on neighbouring states, but it has definitely made a difference in abating the drought that plagued the region in 2015 and 2016. But while Maharastra was fortunate enough to get China’s help in the art of cloud seeding, poorer states will undoubtedly have more trouble finding the money to spend on expensive cloud seeding operations.

Conflict will occur when climate change causes there to be more frequent, and longer, droughts. While we need to be doing our best to limit the effects of climate change, the new US administration seems to have no interest in acknowledging this need. So the best we can do is to reduce our consumption of water intensive crops such as almonds, and other nuts. They may be tasty, but our consumption of them only sends positivity back to farmers who are just trying to do what will make them the most money. That is reasonable, but as long as this trend continues, California and other regions producing crops that require high volumes of water will continue to drain water from every possible source to continue to produce the economically successful crops. If we are to avoid future water wars, then we should be making our water use more efficient so that the effects of the inevitable droughts are lessened. Cloud seeding should be our last resort, but unless we change our water usage, then it may be our only option, and only a matter of time before someone feels that they are being disadvantaged by someone else’s amount of rainfall.

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