The safety of cloud seeding remains a hypothetical concern. Questions as to its efficacy are much more immediate.
“They can tell how much precipitation they’re producing. What they can’t tell is how much makes it to the ground,” Silber says.
Walker says analyses of his programs show anywhere between a 10 to 22 percent increase in precipitation from seeded clouds versus non-seeded clouds.
“That doesn’t mean you get 22 percent more water on the ground over the whole state of New Mexico,” Walker says. “We can’t seed the clear blue sky. But when there are clouds…you’re going to get more water out of them.”
There’s a problem with any attempt to measure the effects of cloud seeding. Advanced radar can identify clouds that are similar. But clouds are like the snowflakes they’re made of—no two are alike. The sky is not a laboratory. Experiments cannot be repeated.
“There’s no control system,” Gleick, the water policy expert, says. “They’re sort of waving their arms.”
The National Academy of Sciences completed a comprehensive review of weather modification research in 2003. University of Virginia professor Michael Garstang, who led the review, later told a US Senate subcommittee “there still is no convincing scientific proof” that cloud seeding works—but that it might work sometimes.
Garstang concluded that, whatever uncertainties remain, “weather modification should be viewed as a fundamental and legitimate element of atmospheric and environmental science.” In part, he reasoned that people like Walker would keep seeding, proof or no proof.
This is where Walker’s philosophical side shows. “Clouds are living animals: They all die,” he says. “People say, ‘I saw you fly into that cloud and it went away.’ There’s no cloud out there today that was there four days ago. Clouds live and clouds die. People live and people die.”
Walker became a rancher after flying in the Navy. He left the Texas House of Representatives in 2001 and formed SOAR. He doesn’t fly the seeders much anymore. “I don’t need the hours,” Walker says. “I’ve seen the world from 25,000 feet.”
Rainmaking could be the biggest job he has ever had. “I miss being in the Legislature, but how much more important could it be to provide water in the ground in our part of the state?” Walker says. “Without our irrigated farmers, my part of Texas pretty much dries up. We still have a courthouse, but we don’t have near as many workers…so people move away and our school gets smaller. Pretty soon your schools are so small your kids have go to Denver City.”
But, like most arguments, this one comes back around to money.
Pumping water drains the bank accounts of farmers in Walker’s seeding area. “We have 90,000 acres of irrigated land in Yoakum County. If you put a pencil to that, it’s $18 million that’s spent just in pumping costs. If I’m only effective in reducing their pumping by 5 percent, that’s $900,000,” Walker says. “Your banker will buy that all day long.”
The farmer downwind might not be so happy. It is foreseeable he might conclude Walker made those inbound clouds drop their loads prematurely.
“A lot of cloud seeding, if you assume it’s working, is taking water from somewhere else. Who is speaking for the downstream user?” Gleick says.
Advocates insist cloud seeding doesn’t rob Peter to pay Paul. “You’re not really reducing the amount of rainfall; you’re just changing the pattern a little bit,” Silber says. “We don’t actually destroy water. We just kind of borrow it.”
That may be true, but people and their crops aren’t the only things that need water. “Maybe the systems that are being hurt are ecosystems that don’t have a voice,” Gleick says.
Indeed, the long-term consequences of cloud seeding simply cannot be predicted and could have the same scale of impact as carbon fuels have had on the climate.
And then there’s the lawyers: Nobody knows who owns the clouds.
New Mexico’s 1965 weather modification law, partly authored by Conrad Keyes, claims for the state “all moisture on the atmosphere which would fall.” That law remains untested.
Eckstein, of the International Water Law Project, knows of no cases where someone has sued over stolen rain—but he thinks they’re coming. In Colorado last year, a woman wanted to collect the rain falling from her roof in barrels. The state denied her a permit, under the dubious theory that the water would otherwise flow into a stream to which someone else has rights.
“People are duking it out over water: nothing new. But it’s going to get worse,” Eckstein says. “I don’t think it’s so far-fetched that they’ll start duking it out over water in the atmosphere.”
Eckstein frets over the morality of water use as much as the legality. He says society lacks a “water ethic—making decisions not based on property rights or economics, but in terms of right and wrong, good and bad.” Society regulates the quality of water—which is why you can’t dump toxic sludge into rivers—but when it comes to quantity, money rules.
Cloud seeding dodges the ethical question: Instead of trying to wring more rain from a passing cloud, shouldn’t people make do with what they have?
“Cloud seeding ain’t the silver bullet. It ain’t gonna—ain’t? Isn’t. It isn’t going to fix our water problems,” Walker says, fixing his Texas grammar. “It’s one piece of the puzzle. We’ve got to conserve all we can.”
It’s a little perverse to talk about conservation in a drought.
Mike Cone farms more than 2,000 acres—wheat and corn, mostly—in Quay and Roosevelt counties. He remembers when the state of New Mexico started funding cloud seeding there, back in the ’90s. Cone didn’t know about the technique until he went to a workshop.
“They made it sound like they were going to make it rain out of the blue sky. People said…that’s a bunch of hogwash,” Cone says.
Then Gary Walker’s airplanes came, chasing clouds that brought rain.
“It worked,” Cone says. “It did some good things.”
He hopes to see those planes again soon, trailing silver smoke behind them. SFR