After studying this dynamic, Hoffman suggested a scheme to weaken a hurricane or shift its path by heating and cooling the atmosphere in complex patterns. While his plan would, theoretically, help tame the weather, we have no reliable way to heat or cool the atmosphere over large enough areas to move a massive storm. “So today,” Hoffman says, “while I can demonstrate that steering a hurricane is possible using computer simulations, we still don’t have a practical way to do it.”
Another hurricane-moderating hypothesis, this one advanced by Daniel Rosenfeld of Hebrew University of Jerusalem and William Woodley, an independent weather-modification researcher based in Colorado, holds that seeding a hurricane’s lower reaches with microscopic dust particles—perhaps microbits of salt—would generate minute water droplets by giving the vapor something to attach to. The droplets would eventually be carried into the storm’s higher altitude, cooling the hurricane through evaporation in the same manner that sweat cools human skin. As the droplets evaporated, they would cool the air in the lower levels of the storm, diminishing its intensity. “Our simulations show that this would be the outcome,” Woodley says.
TELL IT TO THE JUDGE
Even as enhanced computer modeling and more precise measurement bring control of extreme weather closer, those pushing the envelope find themselves facing the same hurdle as Bernard Vonnegut and his colleagues at General Electric half a century ago: the risk of getting sued.
“So here we are, back to weather modification’s critical issue,” says Michael Garstang, distinguished research professor emeritus of environmental sciences at the University of Virginia. “If you cannot predict very precisely what would have happened with, say, a hurricane before you began manipulating it, you’ve left yourself wide open to litigation. There’s just too big an opportunity for people to say: ‘You created this. You made it worse.’”
Charles Hosler agrees. “That’s exactly why there will never be large-scale weather modification or weather control in America. All weather is good for somebody and bad for somebody else.” When altered weather causes a problem for people, he contends, those people are likely to sue.
On this subject Hosler speaks from experience. Along with colleagues, he was once sued by a sightseer riding a ski lift. After the lift’s motor was hit and halted by lightning, the man jumped rather than wait for rescuers; on landing, he broke his leg. Then he discovered that Hosler and his team had been studying thunderclouds nearby. Soon all parties were involved in a lawsuit that was eventually tossed out of court.
Hosler recalls another colleague, this one working in hail abatement research in Pennsylvania, who ran afoul of local fruit farmers who worried that the effort might cause a drought and ruin their livelihood. They reacted by shooting bullets into the sky, hitting a plane flown by student pilots. “People, they get really emotional about their weather,” Hosler says.
If getting sued over a little lightning has some scientists in a tizzy, imagine the risk for those who seek to change the climate in a major way. Nevertheless, some mavericks feel we have no choice as we deal with global warming. Astrophysicist Gregory Benford of the University of California at Irvine, for instance, suggests dispersing tiny particles into the upper atmosphere to reflect sunlight away from us.
And then there’s Roger Angel, an astronomer and optical scientist at the University of Arizona who, working under a NASA grant, seeks to launch trillions of two-foot-wide disks of transparent film into orbit around Earth, a million miles up. The disks, each 250 nanometers thick and tended by “sheepdog” spacecraft to keep them in place, would shade us just enough to reduce sunlight by roughly 2 percent, cooling the planet back to preindustrial temperatures and perhaps moderating some of the destructive weather we have had in recent years.
“I estimate that the program would take 20 years and cost about $5 trillion,” Angel says. But what if, once shaded, Earth begins to overcool? Angel has a contingency there. “Over time, these disks will want to drift out of orbit. We could make it so they stayed in place for only so long.”
WHO WILL STOP THE BEIJING RAIN?
On the 8th of August, 91,000 people will be sitting in an open-air stadium in Beijing for the start of the 2008 Summer Olympics. With thousands of athletes in competition and millions of people watching the event on television, the last thing the Chinese government wants is a rainstorm to spoil this well-planned spectacle.
Tinkering with the weather is old hat for the Chinese, who have employed various cloud-busting techniques to trigger rainfall in their drought-plagued northern provinces, an area that includes Beijing, since the 1950s. For the Olympics, the world’s largest weather modification bureau will set up several banks of rocket launchers outside the city to blast threatening clouds with silver iodide and force them to release their rain before it reaches the Olympic stadium. The bureau has also been practicing a less well-honed strategy that involves overseeding the clouds to actually prevent rainfall; this technique increases the number of ice crystals in a cloud but decreases their mean size, which makes them less likely to fall as rain.
“None of these techniques is a proven technology,” says Roelof Bruintjes, an expert in weather modification at the National Center for Atmospheric Research in Colorado. “I am very skeptical of their having any chance of success.” Of course, the Chinese know full well that weather control is still more art than science. They are just hoping to beat the odds, which, according to historical records, call for a 50 percent chance of rain sometime during the events.
Patrick Huyghe
