"It wasn't that long ago, 10 to 12 years ago, that we had $10-a-barrel oil. So it certainly has dramatically risen, and yes, economists will say that you always want to look at supply and demand conditions, and this time around, it's really demand," says Walden, a North Carolina Cooperative Extension economist and professor of agricultural and resource economics.

"Supply is increasing, although it is increasing at a very slow rate, and in fact, the big set of countries that are really pushing higher supplies are countries in the former Soviet Union," Walden adds. "But we have seen supply increase. What's really pushing the price up, therefore, is big increases in demand.

"And again, it's a story we've talked about before. It's not so much demand from the developed countries, like Europe, Japan and the U.S. But it's increases in the demand from the developing countries, those countries whose economies are expanding very rapidly, such as China and India.

"So far, people look around and they find that the higher oil prices really haven't adversely affected the economy. You would think that the stock market would go into a nosedive with $100-a-barrel oil. It's not, and I think it is precisely because this is a demand-driven increase in price. If it was a supply driven increase in price - that is, supplies were actually contracting as we had in the 1970s - then I think that would lead to declines in the stock market and probably recessions," Walden says.