PRESIDENT BUSH’S hopes for the Arctic National Wildlife Refuge came one step closer to reality last week. While Congress must still pass a law to allow drilling in the refuge, the Senate voted to include oil revenues from such drilling in the budget, making eventual approval of the president’s plan more likely.

Yet the debate over drilling in the Arctic refuge has been oddly beside the point. In fact, it may be distracting us from a far more important problem: a looming world oil shortage.

The environmental argument over drilling in the refuge has often been portrayed as “tree huggers” versus “dirty drillers” (although, as a matter of fact, the north coastal plain of Alaska happens to have no trees to hug). Even as we concede that this is an oversimplification, we should also ask how a successful drilling operation would affect American oil production.

The United States Geological Survey has estimated that the Arctic oil field is likely to be at least half the size of the Prudhoe Bay oil field, almost 100 miles to the west. Opening that oil field was like hitting a grand slam: Prudhoe Bay, which has already produced more than 13 billion barrels, is the biggest American oil field. (I was once at a party with a bunch of geologists from Mobil Oil when an argument broke out: who discovered Prudhoe Bay? Everybody in the room except me claimed to have done so.)

Unfortunately, you don’t hit a grand slam in every at-bat. The geological survey estimates that the Arctic refuge could produce at least half as much oil as Prudhoe Bay. It is also possible, however, that the refuge could produce no oil at all – it often happens in the oil industry. At the other extreme, the upper range of the geological survey’s estimate soars to 16 billion barrels. Although the geologists at the survey are widely respected, the upper ranges of their petroleum estimates for the refuge have drawn criticism, sometimes expressed as giggles, from other petroleum geologists.

Despite its size, Prudhoe Bay was not big enough to reverse the decline of American oil production. The greatest year of United States production was 1970. Prudhoe Bay started producing oil in 1977, but never enough to raise American production above the level of 1970. The Arctic refuge will probably have an even smaller effect. Every little bit helps, but even the most successful drilling project at the Arctic refuge would be only a little bit.

But if the question of whether to drill in the Arctic National Wildlife Refuge is the wrong one, what’s the right one? In 1997 and 1998, a few petroleum geologists began examining world oil production using the methods that M. King Hubbert used in predicting in 1956 that United States oil production would peak during the early 1970’s. These geologists indicated that world oil output would reach its apex in this decade – some 30 to 40 years after the peak in American oil production. Almost no one paid attention.

I used to work with Mr. Hubbert at Shell Oil, and my own independent research places the peak of world oil production late this year or early in 2006. Even a prompt and successful drilling operation in the Arctic refuge would not start pumping oil into the pipeline before 2008 or 2009.

A permanent drop in world oil production will have serious consequences. In addition to the economic blow, there will be the psychological effect of accepting that there are limits to an important energy resource. What can we do? More efficient diesel automobiles, and greater reliance on wind and nuclear power, are well-engineered solutions that are available right now. Conservation, although costly in most cases, will have the largest impact. The United States also has a 300-year supply of coal, and methods for using coal without adding carbon dioxide to the atmosphere are being developed.

After world oil production starts to decline, a small group of geologists could gather in my living room and all claim to have discovered the peak. “We told you so,” we could say. But that isn’t the point. The controversy over the Arctic National Wildlife Refuge is a side issue. The problem we need to face is the impending world oil shortage.

Kenneth S. Deffeyes, a professor emeritus of geology at Princeton, is the author of “Beyond Oil: The View from Hubbert’s Peak.”