Former Federal Reserve Chairman Alan Greenspan said that inflation rates will be higher by 2012 than they are now.

They "will be higher in five years," Greenspan said at an event while promoting his book, "The Age of Turbulence," in London today. "You have to be very sensitive to the fact that inflation pressures could well get out of hand."

He also said that assessing the outlook for U.S. interest rates is "harder" now than when he was chairman.