NEW YORK (CNN/Money) - Economists agree that oil prices have already jumped enough to take a bite out of the nation's economic growth. But what they can't agree on is whether this downswing could spiral into a full-blown recession.

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Oil prices jumped yet again Monday, topping $55 a barrel for U.S. light crude and trading in record territory, though prices then backed off a bit and were trading below that level.

The risk that rising oil poses to the world's largest economy is a concern for everyone from Federal Reserve Chairman Alan Greenspan to OPEC.

An unscientific poll of nearly 25,000 CNN/Money readers last week found almost half believe rising oil prices will throw the United States into a recession next year, and while 21 percent said oil would not spark another downturn, another 29 percent thought it was too early to say.

Greenspan said Friday he believed that the economy should be able to weather jump in prices, even though the rise in oil has shaved three-quarters of a percentage point from economic growth this year.

But he warned that the risks from "serious negative consequences" would grow if oil moved "materially higher."

Meanwhile, OPEC cut its forecast of oil demand for next year, pointing to slower-than-expected economic growth worldwide, partly due to the recent rise in prices.

Greenspan said one of the reasons for his belief that the latest increases won't cause a recession is that, adjusted for inflation, oil now is still well below the highest prices hit after the 1980 oil shock.

The $38-a-barrel peak then would be about $79 in today's dollars, said Fadel Gheit, Oppenheimer oil analyst. In 1990, when Iraq invaded Kuwait, oil approached $40 a barrel -- equal to $60 to $65 in 2004 dollars, he said.

But Gheit holds the minority view that today's oil price levels are already enough to cause an economic contraction.

"We're the walking wounded," he said. "We've already been hit, and in the next three or four months is when we'll stumble."

But even Gheit noted the economy today is far less dependent on oil than it was in the 1970s or 1980 oil shocks.

"Our dependence is almost one third of what it was 30 years ago," he said. "We're moving into more of a service economy, not dependant on smokestack industries. Thirty years ago there was no Microsoft."

Robert Brusca of FAO Economics noted that just about all past recessions were preceded by an oil price shock. He said Monday that current prices, coupled with sluggish job growth, falling consumer confidence and the Fed raising interest rates, pose a serious threat to economic growth.

"Unless oil does a quick about-face I'd say things look pretty grim," he said.

Other economists aren't quite as concerned, although most say oil's already had a significant impact.

"I think energy affects us at every price. As we go marginally higher, growth forecasts get marginally weaker," said Steven Wieting, senior economist at Citigroup.

"At roughly $50, oil should be holding back GDP (gross domestic product) growth by a full percentage point in the year to come. Fortunately, we have more than a percentage point to give." GDP is the broadest measure of the nation's economy.

But even some of those who say $50 oil will have only a limited effect admit they're concerned about how fast prices have risen. In little more than four weeks, they've skyrocketed about 25 percent.

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"The problem we have had in the past four weeks is that the speed of the increase is unprecedented," said A.F. Alhajji, energy economist at Ohio Northern University. "We've been talking about economic growth in the face of $50 oil for a while, but we were talking about it increasing gradually."

Still, other economists say they're not overly concerned about recession yet, despite past oil spikes having just such a result.

"There are times when the economy is quite vulnerable, so a gentle push (from oil) can tip the economy into actual recession," said Anirvan Banerji, director of research at the Economic Cycle Research Institute, which forecast the 2001 recession based partly on the oil price increase seen in 2000.

But he said the economy is showing greater strength today in other measures than it did in 2000.

"A rise in oil prices might take a bite out of growth. But is there a magic number of what's enough to trigger recession? No," he said.

John Silvia, chief economist at Wachovia Securities, also said it will take a combination of high oil prices and other factors, such as significantly higher interest rates, to spark a recession. But he said some of the worst-case scenarios for oil prices do worry him.

"I think if you had $70 oil, and the Fed were to continue to raise interest rates to fight inflation, that could cause a problem," Silvia said. "I think there's a certain breaking point where that the price of energy alone is so high that it changes the psychology of both businesses and consumers. I think $80 would probably break the back."  

-- This is an update of a story that originally ran Oct. 11. Reuters contributed to this report.