By David Goodstein
This article is adapted from a talk that Caltech vice provost and professor of physics and applied physics David Goodstein presented at an April 29 program of the Institute support group, the Caltech Associates. Goodstein’s new book, Out of Gas: The End of the Age of Oil, was published in February by W. W. Norton. On December 5, the New York TimesBook Review named Out of Gas one of its 100 Notable Books of the Year.
In the 1950s, it was not Saudi Arabia but the United States that was the world’s greatest producer of oil. Much of our military and industrial might grew out of our giant oil industry, and most people in the oil business thought that this bonanza would go on forever. But there was one gentleman who knew better. He was an oilexploration geologist named Marion King Hubbert.
In about 1950, Hubbert realized that the trajectory of oil discovery in the continental United States was going to be a classic bell-shaped curve, for the decades from 1910 to 1970, in billions of barrels per year (see figure 1, below). He also saw that there would be a second bell-shaped curve that would represent production, or consumption, orextraction. The oil industry likes to call it “production,” but the industry doesn’t really produce any oil at all. It does, however, reflect the rate at which we use the oil up. Perhaps you could call it supply.
Hubbert realized that using what he knew in 1950 about the history of discoveries, along with what was already known about consumption, and a little mathematics, he should be able topredict that second bell-shaped curve. And so he did (see figure 2, below). The red, bell-shaped curve is the kind of curve he predicted. The black points are the actual historical data, and the uppermost point represents what has come to be known as Hubbert’s Peak. Obviously, he was doing something right.
The situation worldwide is a little less well-determined. A third graphicprovided by the energy conglomerate BP, shows what the world’s known crude oil reserves are (see figure 3, left-hand graph, below). The amount that we have now is a trillion barrels of oil. So people in the industry might say, we have a trillion barrels just sitting there waiting to be pumped out of the ground; we’re using it up at a rate of about 25 billion barrels a year, and so we have 40 moreyears to go—there’s nothing to worry about. But as Hubbert has shown us, that’s the wrong way of looking at it .
Before we leave that curve, though, I want to point out that a sudden jump of 300–400 billion barrels of oil in OPEC (the Organization of the Petroleum Exporting Countries) reserves occurs in the late 1980s (see figure 3, left-hand graph, above). But there were no significantdiscoveries of oil in OPEC countries during that period. What happened instead is that OPEC changed its quota for how much each country could pump on the basis of what it claimed in reserves, and politicians discovered 400 billion barrels of oil without ever drilling a hole in the ground! This helps us to understand how undependable these numbers are for worldwide proven oil reserves.
As you cansee, the curve that traces the historic record of oil discovery peaks around 1960. In other words, Hubbert’s peak for oil discovery came and went 40 years ago.
The curve for oil usage, as you can see, is a rising curve and will become a bell-shaped curve eventually. Note that for the last quarter century, we’ve been using oil faster than we have been discovering it. World reserves should havedecreased during that time by about 200 billion barrels. Instead, as we’ve seen, they’ve increased by 400 billion barrels. In any case, it should be possible, given this much information, to make a prediction similar to the one that Hubbert made for the continental United States for worldwide oil production.
One such estimate was published in 1998 in Scientific American. It predicts that we will...