More likely it is cloud seeding, a technique used to extort water from reluctant clouds, and one soon to be practiced in Los Angeles County, California, which plans to kick off an $800,000 cloud-seeding project in the San Gabriel Mountains northeast of the city this winter to combat drought.
Southern California is as dry as it has been in a decade, and fires sweep the region from west of Santa Barbara to the southern tip of Owens Lake, east of Death Valley. Officials watching the conflagration hope the measure will boost rainfall and raise the level of local reservoirs.
It won't be a new venture for the county, which has been seeding since the 1950s, but it will be a resumption of a program discontinued seven years ago when civil engineers began to worry about mudslides in some areas stripped of vegetation by brush fires. It's a valid concern after a 1977 landslide in the San Gabriel mountains sent a 20-foot-high wall of mud down the mountainside to destroy everything in its path and killed 13 people.
That worry remains the same, but weather modelers are now arguing that the consequences of continued drought in the region may exact even more severe penalties. This spring, Southern California growers started stumping their avocado trees to protect the more fragile, water-loving citrus. Earlier this month, in response to a predicted heat wave, Gov. Arnold Schwarzenegger declared a heat emergency. This, on top of the earlier declaration of a statewide drought, and continued wildfires, has led President Bush to declare most of California a disaster zone.
Cloud seeding is an iffy venture. Scientists and others who practice it can't be sure if it is their chemicals, or Nature, delivering the rain. Some experts argue that funds would be better spent promoting water conservation. Proponents of the idea cite figures from the California Water Plan Update (pdf), which estimates from 2 to 15 percent more annual precipitation (or runoff from melting in the Sierra Nevada range) as a result of seeding.
The National Academy of Sciences, in 2003, denied the claim, saying that, "...six decades of experiments and applications (have) failed to produce clear evidence that cloud seeding can reliably enhance water supplies on a large scale". The Academy also recognized that, since cloud seeding is cheaper than the effects of drought, it is likely to continue. Like the legendary rainmakers of the American frontier, modern rainmakers, like North American Water Consultants, find their phones ringing off the hook. The money to pay for this newest form of prestidigitation seems to be something that desperate farmers and regional governments are willing to scrape together.
Waiting until it's an actual drought, though - as is currently the case in California, most of the Southwest and Southeast, and even as far north as Wyoming and North Dakota - makes the enterprise dubious at best. The key to cloud seeding is, obviously, clouds, and during drought conditions the odds of finding clouds that can be "geo-engineered" to give up rain are few and far between. As climatologist Ken Caldeira of the Carnegie Institution points out, cloud seeding works in marginal situations. That is, if the air is damp and the clouds have the potential, the chemicals used may be able to instigate rain. "However, no amount of cloud seeding will produce rain from a dry atmosphere," according to Caldeira
Most effective rainmaking takes place when the possibility already exists, and - for California - the most effective policy to date has been seeding the clouds over the Sierra Nevada mountains in winter (a policy endorsed by the Los Angeles Department of Water and Power until quite recently). This delivers a more than adequate snow pack to feed both the southern and northern half of California's aquifers in a good year. What it does for Sierra residents is another story, but digging out of 12-foot snowdrifts is part of the mountain mystique no "flatlander" will ever understand.
California isn't the only location looking to cloud seeding for much-needed moisture. Similar efforts are underway in North Dakota, Utah, Colorado, Texas and Wyoming. In 2005, Wyoming instituted a five-year, $8.8 million cloud seeding program to bolster snow pack in the mountains. The program has worked, according to some. The eastern half of the state is in the grip of a multi-year drought, and United States Geological Survey end-of-June figures show runoff at its lowest in more than 70 years - except in certain areas like the Wind River range, where snows from last winter fell so deeply they still haven't melted across much of the range. This, one supposes, is largely due to experiments last winter which saw the dumping of more than 23 pounds of silver iodide from November to March. Residents are elated, trout fishermen perhaps less so. Silver is an aquatic toxin (but more on that later).
Wyoming's program is being tracked by the National Center for Atmospheric Research in Boulder, Colorado, and scientists there hope that the final results will either put the cloud-seeding debate to rest or spark renewed interest in other areas. .
China and Russia are also getting into the act. In China, scientists are using cloud seeding not to deliver rain, but to prevent it during the Olympic Games. The Russians - using the same technique (modified with cement powder) to create the same effect - ended up dropping a solid concrete block on a suburban Moscow home. If, as Reuters contends, the Russians have been practicing weather modification for decades, more practice will be needed to perfect their technique.
The tinfoil-hat crowd warns us that cloud seeding - which they call chemtrails - will lead to mind control, or at the very least a loss of mental capabilities. Paranoia is rampant in America, especially after nearly a decade of Bush administration policies that have decimated both the economy and the environment (to say nothing of social welfare programs). I sympathize with this extremist fringe, mostly because I have observed chemtrails in the sky over my precipitation-blessed state on perfectly cloudless days, which forces me to question the relationship between these persistent contrails and weather modification. Even so, seeders argue, the chemicals typically used in cloud seeding (silver iodide, hygroscopic chemicals like potassium chloride and sodium chloride, expanded liquid propane, and possibly aluminum or barium sulfate) are only moderately toxic in the concentrations delivered by airborne mechanisms.
Silver, as found in the bodies of mammals (including humans) has no known biological purpose and is suspected of being a contaminant. In aquatic environments, however, it is one of the most toxic metals known, and is lethal in many species of aquatic plants, animals (like frogs and trout) and phytoplankton, in ranges as low as 0.3 to 0.6 picograms per liter (pg/L). Tests for concentrations of silver in water supplies in non-seeded and seeded areas showed a range of 0.17 pg/L for non-seeded, and up to 0.6 pg/L for seeded areas. This is the bad news for trout, and the people who fish for them.
A 1990 study also showed that exposure to dust containing relatively high levels of silver compounds such as silver nitrate or silver oxide may cause breathing problems, lung and throat irritation and stomach pain. Another study shows four month's of exposure may have an effect on motor areas of the brain, or cause an enlarged heart, and some studies suggest a link between silver exposure and kidney problems. In addition, some earlier Cloud-seeding operations may have used potassium perchlorate in the past as a component in the flares (rockets that disperse the chemicals). Other components, like aluminum and barium sulfate, are definite lung irritants. Their effects on ecosystems have not been studied sufficiently to anticipate long-term effects in the amounts typically used in cloud seeding.
Overall, cloud seeding is another manifestation of the geo-engineering mania that has overtaken regions, and nations, as the effects of global warming, such as extreme drought, become more apparent. Most are band-aid solutions that allow the underlying infection to proceed unobserved. This is not helpful in the long term, and we must begin to deal with emissions before no amount of climate modification can preserve the life-sustaining potential of the only planet that we can call home.
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