The infamous Superfreakanomics chapter touches on a number of these issues.
So just how does it work? Personally it is hard to believe that there are not serious side affects from the rain on demand idea. Surely this means someone, somewhere is going to get less rain.
I like the idea of the lone "greenfinger".
Quick Study: Climate Engineering [Readers Digest]
Chinese and Russian scientists claim to make it rain or snow on command. But can we slow global warming with massive operations called geoengineering? A growing number of experts say yes—and that radically altering our environment may be our last, best hope of avoiding disaster. From orbiting space mirrors to artificial trees to brighter clouds, here's what's under discussion.
Risks vs. rewards. Like any untested tech-nology, geoengineering harbors unknown risks. An artificial cooling of the earth could disrupt global weather patterns, bringing drought and famine to parts of North Africa, India, and China.
What it would cost. Hoisting mirrors or sun shields into space could cost trillions, according to a September 2009 report by the United Kingdom's Royal Society. Stratospheric aerosols, which could block solar radiation and cool the earth, could cost tens of billions of dollars a year; cloud brightening, which reflects sunlight away from the earth, $2 billion a year. Expensive, yes, but to some economists, geo-engineering is worth pursuing. One well-regarded but controversial report projects that stratospheric aerosols could carry a benefit 27 times higher than their cost; it also suggests that marine cloud brightening could save $7.5 trillion by reducing the damage caused by global warming.
The "Greenfinger" scenario. David Victor, a climate policy expert at the University of California, San Diego, worries about the prospect of a single nation taking matters into its own hands. "It could be a Hail Mary pass by a country getting hammered by global warming," he says. A wealthy individual—Victor calls him a "lone Greenfinger"—could also choose to go it alone. To prevent unilateral action, experts need a framework for researching geoengineering and deciding, as Victor says, "who gets to put their hand on the thermostat." One such meeting, organized by the nonprofit Climate Institute in Washington, D.C., will take place this month.
Contain the carbon. Removing carbon from the air and storing it underground, or reusing it for fuel, would help slow and possibly reverse global warming. This solution, says David Keith, a physicist at the University of Calgary, would cost considerably less than what we might spend converting carbon-fed electrical to rooftop solar power. England's Institution of Mechanical Engineers has even come up with a proposal to line highways with "artificial trees" that would collect carbon dioxide at rates far exceeding those of lazy natural trees and convert it into a form that's easily collected and stored.
Deflect, deflect, deflect. National Center for Atmospheric Research climatologist John Latham, along with University of Edinburgh engineer Stephen Salter, has designed a novel way of "brightening" clouds: a fleet of remote-controlled, wind-powered ships that would spray a fine seawater mist into marine clouds. "It's established that if you have a lot of little drops instead of a few big ones, then the clouds are more reflective," says Latham. They hope to increase that reflectivity by 10 percent, which, they say, would hold the earth's temperature steady until at least 2050. Keith is devising a reflective metal particle that could levitate itself above the ozone layer to reflect heat from the sun back into space, although his main focus remains on reflective aerosols. Washington-based Intellectual Ventures Lab, owned by former Microsoft guru Nathan Myhrvold, has proposed an 18-mile-long hose suspended from balloons that would pump liquefied sulfur dioxide (a gas emitted when volcanoes erupt) into the stratosphere.
Show them the money. Last year, a House of Representatives committee held its first hearing on climate engineering but shied away from funding any proposals. "We need a balanced, open, publicly funded research program," says Keith.
The Back-and-Forth …
"A tiny investment in climate engineering might be able to reduce as much of global warming's effects as trillions of dollars spent on emissions reductions."
—Bjorn Lomborg, the Copenhagen Consensus Center
"Geoengineering is a far-fetched, pie-in-the-sky dream to avoid having to make the emissions cuts we have to make now."
—Michael Crocker, spokesman for Greenpeace
The Time Line
874–853 bc: The prophet Elijah scales Mount Carmel in Israel and prays for rain. It pours.
400–200 bc: Bronze Age cultures in China and Southeast Asia bang the kettle gong in rainmaking ceremonies.
1824: Thomas Jefferson calls for an index of the American climate to monitor the effects of massive forest clearing and marsh draining.
1830s: James Espy, the first national meteorologist, proposes lighting huge fires along the Appalachian Mountains to control and enhance the nation's rainfall.
1901: Swedish meteorologist Nils Ekholm publishes a research paper on the possibility of climate modification.
1932: The U.S.S.R.'s Leningrad Institute of Rainmaking is founded.
1946: Researchers at General Electric spread the word about cloud seeding, leading to a commercial boom in weather-modification technology.
1960–1961: The U.S.S.R. reports clearing clouds over 12,000 square miles.
1965: President Lyndon Johnson's Science Advisory Committee issues the first high-level government report to include a discussion of ways to manipulate climate.
1966: The U.S. tests cloud seeding in Vietnam.
1977: Russian physicist Mikhail Budyko proposes using planes to release sulfur dioxide into the stratosphere, creating, in effect, a fake volcanic eruption.
1992: The National Academy of Sciences report "Policy Implications of Greenhouse Warming" advocates climate control.
2006: Nobel-winning chemist Paul Crutzen suggests launching sulfur dioxide into the stratosphere with weather balloons instead of planes.
June 2007: A Carnegie Institution report suggests using sulfate particles to roll back rising global temperatures, returning the planet to the average temperatures of 1900.
February 2009: Desperate to end a drought, Chinese meteorologists fire explosive rockets loaded with chemicals into the sky. A snowfall blankets Beijing.
October 2009: China claims to have prevented rain during its 60th-anniversary parade by sprinkling liquid nitrogen into clouds.