Lake Mead dry as a bone?

For the better part of the past decade, the region's water authorities have attempted to manage the twin challenges of record drought and demand along the Colorado River. The sinking surface of Lake Mead underscores the urgency of long-term planning, conservation and construction to stretch finite supplies as far into the future as possible.

Water officials get plenty of other reminders to focus on the future. Every year or so, environmentalists come forward with research that predicts imminent doom for Lake Mead and the Colorado River basin. The latest study is "When Will Lake Mead Go Dry?" Scheduled for publication later this year in Water Resources Research, the piece places Vegas-style odds on the huge reservoir disappearing from the Clark County landscape.

The study, co-authored by Tim Barnett and David Pierce of the University of California-San Diego's Scripps Institution of Oceanography, lays even money on the lake running dry by 2021, even money that levels fall low enough to halt power generation at Hoover Dam by 2017, and 10-to-1 odds that Lake Mead goes dry in just six years.

"The point is this is coming in 10 years, not 20 or 30 or 40. We're looking it in the face now," Mr. Barnett says.

The peer-reviewed science behind the study relies on worst-case-scenario assumptions regarding climate change. Essentially, the men are making the case that the cancer of mankind would bring about the slow death of Lake Mead, but global warming will act as a coup de grace.

It's perfectly reasonable -- and responsible -- to point out that continued drought and increased demand will eventually leave Lake Mead useless as a reservoir and a recreation destination. And studies such as this one certainly keep an appropriate level of attention on the West's most critical issue.

But these doomsday predictions are getting awfully tiresome. Environmentalists issue them for three reasons: to strike fear in the gullible, to raise money from their allies and to spur lawmakers and the courts to craft policies they agree with.

Predictions such as these virtually never come true. From Thomas Malthus in the 1798 to Paul Ehrlich in the 1970s, the forecasters of famine, abandoned cities and desolated economies always look like fools in the end because they refuse to take into account the ingenuity and enterprise of the human race.

Lake Mead go dry? The federal government and the states that depend on the reservoir simply won't let that happen. The stakes are too high. We'll wager that all the farms in California's Imperial Valley, which suck up the lion's share of river water, will go fallow before Lake Mead does.

As Marc Reisner pointed out in "Cadillac Desert," the seminal work on Western water issues written more than 20 years ago, drought is, historically, a normal condition on the Colorado. The supply provided by the Colorado River likely isn't sustainable in the century ahead. These conclusions were made long before the bogeyman of human-caused global warming was invented by the greens to rein in capitalism, limit human prosperity and give governments even more regulatory powers.

But we'd love to buy some action on the odds provided by Mr. Barnett and Mr. Pierce. They can name the amount at stake. Are they willing to put their money where their mouths are?