Why oil prices will tank

NEW YORK (Fortune) -- High-flying tech stocks crashed. The roaring housing market crumbled. And oil, rest assured, will follow the same path down.

Not everyone agrees. In an echo of our most recent market frenzies, some experts pronounce that the "world has changed," and that the demand spikes, supply disruptions, and government bungling we face now will saddle us with a future of $4, $5 or even $10 a gallon gasoline.

But if you stick to basic economics, it's clear that the only question is when - not if - prices will succumb.

The oil bulls are correct in their explanations of why prices have jumped. It's indisputable that worldwide demand has surged, chiefly driven by strong growth in China, India and the Middle East. It's also true that most of the world's reserves are controlled by governments in places like Russia and Venezuela that mismanage production, thus curtailing supply growth.
But rather than forming a permanent new plateau for prices - as the bulls contend - those forces are causing a classically unstable market that's destined for a steep fall.

But sooner or later the world won't keep paying those prices: Eventually, the price must fall back to the cost of that last barrel to clear the market.

So what does that barrel cost today? According to Stephen Brown, an economist at the Dallas Federal Reserve, that final barrel costs just $50 to produce. And when the price is $125, the incentive to pour out more oil, like homebuilders' incentive to build more two years ago, is irresistible.

It takes a while to develop new supplies of oil, but the signs of a surge are already in place. Shale oil costing around $70 a barrel is now being produced in the Dakotas. Tar sands are attracting investment in Canada, also at around $70. New technology could soon minimize the pollution caused by producing oil from our super-plentiful supplies of coal.

That's just the supply side of the equation. Demand should start to decline as well, albeit gradually. "Historically, the oil market has under-anticipated the amount of conservation brought on by high prices," says Brown. Sales of big cars are collapsing; Americans are cutting down on driving. The airlines are scaling back flights.

We've learned another important lesson from the housing market: The longer prices stay stratospheric, the worse the eventual crash - simply because the higher the prices and bigger the profit margins, the bigger the incentive to over-produce.
It's even possible that, a few years hence, we could see a sustained period of plentiful oil supplies and low prices, meaning $50 or below. A similar scenario occurred following the price explosion in the 1970s and early 1980s. The price spike caused the world to cut back sharply on oil consumption. By the mid-80s, oil prices had fallen from almost $40 to around $15. They remained extremely low for two decades.

An earlier bubble is also instructive. In the early 1980s silver prices jumped from $10 to $50 on the theory that the world was facing a permanent shortage of silver. Suddenly ads appeared asking homeowners to bring their tea sets and jewelry to Holiday Inns for a big price. Silver supplies poured from seemingly nowhere, out of America's cupboards, of all places.
And so it will be with oil. We don't know where the new abundance will come from, from shale, or tar sands or coal or an OPEC desperate to regain market share. We just know that it will appear. With prices like these, it always does.