Think $4 a gallon gas is already too much? Then brace yourself, says one expert.
"The prices that we're paying at the pump today are, I think, going to be 'the good old days,' because others who watch this very closely forecast that we're going to be hitting $12 and $15 a gallon, and then, after that, when world oil production goes into decline, we're going to talk about rationing," Robert Hirsch, Management Information Services Senior Energy Advisor, said on CNBC's "Squawk Box." "In other words, not only are we going to be paying high prices and have considerable economic problems, but in addition to that, we're not going to be able to get the fuel when we want it."
Hirsch argued that the maximum in world oil production has already been hit.
"The idea is that [world oil production] would hit a sharp peak and then drop off, and what's happened is, we've hit a plateau in world oil production, and that plateau has been ongoing since about the middle of 2004," he said.
Those who argue that new technology and new types of energy will solve the problem aren't on solid ground, Hirsch suggested.
"There's no single thing that's going to solve this problem, because it's as massive as one can possibly imagine," he said.