by Calculated Risk on 1/15/2012 06:32:00 PM

A followup to the previous post on the possible impact on oil prices of an Iranian oil embargo, from Brad Plumer at the WaPo: How high oil prices could squelch the recovery

According to a U.S. Energy Information Administration analysis, a $20 increase in the cost of a barrel of oil — roughly what we saw last year — is estimated to shave roughly 0.4 points off GDP growth in the first year alone and boost unemployment by 0.1 percentage points. So if Iran threatens to close the Strait of Hormuz (through which about 20 percent of the world’s oil flows) and prices start screaming upward from $107 per barrel to $120 or beyond, that would put a very noticeable dent in growth.

What’s more, oil shocks tend to have long-lingering effects. The EIA estimates that a $20 price increase continues biting into the economy for at last another year thereafter. James Hamilton, an economist at the University of California, San Diego, has suggested that the consequences of a price spike can persist for several quarters, as the resulting slowdown in consumer spending takes some time to ripple through the economy. That’s true even if the spike is only temporary and recedes quickly.

The recession in Europe, and slower growth in China (as Plumer notes), might offset some of the upward price pressure from a disruption of supply from Iran.

And below is a graph of gasoline prices. Gasoline prices had been slowly moving down since peaking in early May, but have started moving up again. Note: The graph below shows oil prices for WTI; gasoline prices in most of the U.S. are impacted more by Brent prices.

Orange County Historical Gas Price Charts Provided by GasBuddy.com