If the actions – rather than the words – of the oil business’s major players provide the best gauge of how they see the future, then ponder the following. Crude oil prices have doubled since 2001, but oil companies have increased their budgets for exploring new oil fields by only a small fraction. Likewise, U.S. refineries are working close to capacity, yet no new refinery has been constructed since 1976. And oil tankers are fully booked, but outdated ships are being decommissioned faster than new ones are being built.

If those clues weren’t enough, here’s a news item that came out of Saudi Arabia on March 6, 2003. Though it went largely unremarked, the kingdom’s announcement that it could not produce more oil in response to the Iraq War was of historic importance. As Kenneth Deffeyes notes in Beyond Oil: The View from Hubbert’s Peak, it meant that as of 2003, there was no major underutilized oil source left on the planet. Even as established oil fields have reached their maximum production capacity, there has been disappointing production from new fields. Globally, according to some geologists’ estimates, we have discovered 94 percent of all available oil.

The Saudis’ announcement arrived right on schedule – at least, once the three-year delay imposed by OPEC’s anti-U.S. embargo and production cutbacks of the 1970s was factored in. In 1969, the prominent geologist M. King Hubbert predicted that a graph of world oil production over time would look like a bell curve, with a peak around the year 2000. Thereafter, he argued, production would drop – slowly at first, then ever faster.

Hubbert had a track record as a prophet: his 1956 forecast that U.S. domestic oil production would peak in the early 1970s proved correct. Kenneth Deffeyes, who started out in 1958 as a young petroleum geologist at Shell’s Houston labs working alongside Hubbert, became so convinced by the man’s theories that by 1963 he had left the oil business, except for occasional consulting work; he is now a professor emeritus of geosciences at Princeton University. In Beyond Oil, Deffeyes takes readers through Hubbert’s analysis in a highly readable style, even boiling down the complex mathematics into a few pages of graphs.

The prognosis? Deffeyes has no doubt that by 2019, the year in which Hubbert’s theories indicate global oil production will drop to 90 percent of current rates, human ingenuity will have found replacement energy sources (see “What Energy Crisis?”). But Deffeyes is optimistic about the long term only because he believes that by 2010, pressures will grow so intense that they’ll create the resolve necessary to develop a new energy ­economy. In the short term, he foresees continually rising oil prices that force industry after industry closer to the wall. He fears not just escalating resource wars around the world but also mass starvation in some countries, since the 6.4 billion people living on the earth today are fed thanks largely to the successes of the 20th century’s “green revolution,” which, among other innovations, brought petrochemical-based fertilizers into wide use.

Because 15 years ago we failed to begin developing the new energy sources and technologies we need now, Deffeyes argues, in the immediate future we’ll have to rely on what we’ve got. In Beyond Oil, he examines how we might optimize the use of our geologically derived energy sources.

Deffeyes suggests that coal will make a comeback and that Fischer-Tropsch conversion – the process by which the Nazi regime turned coal into gasoline to keep its Panzers running during WWII – might become commonplace. He grants that there’ll be an outcry over the ecological costs of burning coal; similarly, there’ll be much agonizing as nuclear power plants are again rolled out. But Deffeyes believes that M. King Hubbert, whose 1956 paper predicting the U.S. oil production peak is titled “Nuclear Energy and the Fossil Fuels,” was right: nuclear power will be part of our response to decreasing reserves of oil and natural gas, as necessity overrides any political opposition.

Ultimately, says Deffeyes, we may just have to resign ourselves to relying more on coal, wind, and nuclear fission for ­electricity and switching to high-efficiency diesel and hybrid automobiles in order to ration our remaining oil reserves for as long as possible. Abundant energy from fossil fuels was a one-time gift, Deffeyes concludes, that lifted humanity up from subsistence agriculture and has led to a future based on renewable resources.