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Issue 8.01 - Jan 2000


Activate Cloud Shield! Zap a Twister!

Starting now, lightning strikes - on demand.

By Tom Standage

If the US Air Force is to be believed, illegal drugs aren't going away anytime soon. In fact, in the future they'll only cause more problems, because the distributing cartels will have consolidated. They'll have wealth, political power, and, instead of a few guys with submachine guns, entire armies.

Picture, then, a South American cartel of the mid-2090's. It maintains hundreds of fighter planes, thwarting attacks by launching a dozen Russian- and Chinese-made aircraft for every one of ours. Our sole advantage comes from a piece of military intelligence: Cartel pilots won't fly in harsh weather. But this doesn't mean waiting around for the skies to turn - because by then, thunderstorms will be made to order.

First we launch uninhabited aerospace vehicles (UAVs), which, through advanced cloud-generation technology, disseminate cirrus clouds to block enemy surveillance. Next we seed any one of the daily rain showers passing through the region, intensifying it precisely over the target. Then we snuff out our blinded enemy.

Over the course of the next century, the weather will be our most powerful weapon. So says Weather as a Force Multiplier: Owning the Weather in 2025, part of a 1996 Air Force-commissioned report forecasting the technology required to maintain US air and space leadership into the next century. "Current technologies that will mature over the next 30 years will offer anyone who has the necessary resources the ability to modify weather patterns, at least on the local scale," the study says. "Weather modification can provide battlespace dominance to a degree never before imagined. By 2025 it will be within the realm of possibility."

Sound like hyperbole? Ironically, three years after the report was issued, that's what Air Force officials would have you think. "We have no plans to try and modify the weather. It's just too much of a crapshoot in terms of the complex dynamics and huge energy involved," says Brigadier General Fred P. Lewis, the Air Force's director of weather. "How will you guarantee the outcome? How will you create what you want yet avoid kicking off an undesirable or even dangerous weather system?"

Made-to-order thunderstorms, says the military, "can provide battlespace dominance to a degree never before imagined."

Whatever the truth about the military's attitude toward weather modification, the private sector won't wait for Lewis to answer his own questions. One sign of real-world progress has come in a rather ancient-sounding technology: cloud seeding. Introduced in the 1940s, the tactic has made huge leaps of late thanks to a new method known as hydroscopic seeding. In the early '90s, South African researchers began using flares shot from planes to inject water-attracting salts into clouds. In these and other tests, hydroscopic seeding has shown evidence of increasing not only the amount of rainfall, but also the duration and vertical concentration of individual storms.

The most extensive hydroscopic test to date, being conducted in Mexico by scientists from the National Center for Atmospheric Research in Boulder, Colorado, has been running for three years. So far, 99 seeding missions have shown rainfall increases of as much as 40 percent, according to head researcher Brant Foote. Another 50 tests with the same results, Foote says, and he'll consider the evidence conclusive.

While Foote and the military talk of weather enhancement, some of the most important developments are coming in weather suppression. One factor pushing those developments is the ever increasing density of Earth's population. Not only does it amplify the need to move water to drought-afflicted areas, it also intensifies the amount of damage natural disasters wreak. Weather-related catastrophes caused $92 billion in damage worldwide during 1998 and displaced more than 300 million people from their homes, according to the Worldwatch Institute in Washington, DC. Top priority: Mother Nature's ultimate terror, the hurricane.

Hurricanes are fueled by the evaporation of warm ocean water. One way to kill a storm would be to cool the ocean. Given the huge energy investment of, say, towing icebergs, however, researchers have made little progress in this regard. Pushing a hurricane toward land would also kill the storm by eliminating its energy source - but also threaten people and property. That's not an option, of course. But can we make a hurricane think it's over land?

A team of MIT scientists believes so. Led by professor Kerry Emanuel, the scientists are hoping that by applying a chemical coat one molecule thick to the ocean's surface, they can retard the natural heat-transfer process that occurs during evaporation, which would slow the storm. Team member Moshe Alamaro tests materials by pouring tiny amounts of various biodegradable, oily substances into a special test rig filled with seawater. To see how this monolayer material would stand up in the ocean, he agitates the water with a paddle wheel. It's an arduous process. "There are 10,000 types of oil, all with different properties," he says. "We need to have something with a diffusion rate faster than the rate at which waves break, a film that will repair itself quickly."

Using oil to suppress evaporation could also help protect reservoirs. That prospect has attracted attention from Chevron, which has supplied a number of possible monolayer materials and shown an interest in giving the MIT group startup funding. But the team's real hope is one day to spread a monolayer over several hundred miles of ocean in the path of a hurricane, stopping it before it can reach land.

Getting to that point will require a lot more research. The ways ocean spray and wind fuel hurricanes are not fully understood, and some think that smoothing the sea with oil might reduce surface drag and actually intensify the storm. The MIT researchers are constructing a second test rig, incorporating a wind tunnel, to investigate these phenomena.

Their work to date has attracted the interest of Vladimir Pudov, a leading weather-modification scientist from Russia who has expressed interest in joining forces with MIT. According to the recently declassified results of Soviet experiments during the 1980s, Pudov made significant progress in evaporation suppression in the South Pacific.

Rather than coating the ocean surface, Pudov sought a substance that would dissolve in it - and he claims to have developed the ideal compound: a low-cost, ecologically safe, fine white powder called carmidol. "Carmidol suppresses evaporation by no less than 65 percent," he says. "This leads to a decrease of water-air temperature difference and a decrease of the energy flow into the hurricane."

While Alamaro is guarded in his optimism about Pudov's claims, he's excited about the prospect of working with someone committed enough to navigate a ship into a tropical cyclone for the sake of research. "He is a brave man. He gathered crucial data on a storm's thermodynamics and physics, and on ocean spray," says Alamaro of Pudov's trip to the Sulawesi Sea. "But the storm had only 70-mile-per-hour winds. Someone has to go into a real hurricane. When you have money, you can do a lot of things that are otherwise not possible. We're working on a shoestring, and it's getting short."

A standard tropical storm has the energy of 10,000 one-megaton hydrogen bombs. Unlike the MIT crew, Bernard Eastlund, a former research manager at the US Atomic Energy Commission, wants to fight power with power. Eastlund researched the construction of a missile shield for the Department of Defense during the '80s as part of the Strategic Defense Initiative, aka Star Wars. His plan was to superheat the atmosphere at an altitude of 70 kilometers with an array of microwave transmitters, creating a shield of electrons that would prove lethal to incoming missiles.

"Weather modification offers a dilemma not unlike the splitting of the atom. Even if we have no intention of using it, others will."

The death of the Cold War squelched interest in that project, but in 1998 the European Space Agency asked Eastlund to consider potential applications for solar-power satellites - orbiting power stations that would absorb energy from the sun and deliver it via microwave beams to receiving stations on Earth. He immediately thought of weather modification and devised a plan for the Thunderstorm Solar Power Satellite, which would be used primarily to snuff out tornadoes, but could also zap hurricanes and even nudge the atmospheric polar jet stream in an effort to prevent flood rains.

Here's how it would work: Suppose an embryonic tornado is spotted somewhere in America's heartland. A couple of satellites with suitable orbits would be instructed to break off power transmission and switch their microwave transmitters from the usual operating frequency of 2.5 GHz - which allows microwaves to pass unimpeded through clouds and rain, delivering electrical power in any weather - to at least 30 GHz. At these frequencies, Eastlund says, clouds and rain absorb microwaves and heat up. As he envisions it, the satellites would wheel around to warm an area of the storm, suppressing the downdrafts that drive tornado formation.

Although such a scenario sounds far-fetched, Eastlund suggests the main hindrance is not microwave or satellite technology but the limitations of meteorology - an assertion echoed by the Air Force study, in which bullish conclusions also presuppose certain advancements in chaos theory. The solution, in other words, will come not from more sophisticated spaceware but from better weather-predicting software and more computing power. "You've got to have a very good idea of cause and effect," Eastlund says. "I consider computer simulation an important enabler."

In the end, the biggest impediment to weather modification may turn out to be culture, not science. The Air Force report acknowledges the controversy inherent in futzing with Mother Nature, but concludes that we have no choice but to press on. "Weather modification offers a dilemma not unlike the splitting of the atom," the study says. "The lessons of history indicate a real weather-modification capability will eventually exist despite the risk. The drive exists. The motivation exists. The potential benefits and power are extremely lucrative and alluring for those who have the resources to develop it. We cannot afford to be without a weather-modification capability once the technology is developed and used by others. Even if we have no intention of using it, others will."

MIT's Alamaro agrees. The benefits far outweigh the repercussions. "If the hurricane that hit Miami in 1926 hit today, it would cause $75 billion in damage, and New Orleans would be wiped off the map," he says. Indeed, the danger of altering the weather may be surpassed only by the danger of letting nature run its course.


Tom Standage ( is a science correspondent in London with The Economist.

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