Growing evidence suggests American consumers, businesspeople, and political leaders should all be bracing for double-digit inflation, probably as early as 2009.

The relative price stability of the past 15 years is giving way to worsening inflation, despite the recent softening of oil prices. The Consumer Price Index for all items shows the inflation rate averaged 2.6% a year from 1992 through 2007 but has doubled since January, reaching an annual rate of 5.6% in July. By next year, the monthly figure could hit double digits, and the inflation rate for 2009 overall could triple 2007’s 2.85%.

Anyone who hasn’t been living in a cave for the past year knows that oil prices have soared and pushed up the prices of gasoline, diesel fuel, and heating oil. Largely hidden from view, however, have been steep and continuing price increases across the whole spectrum of commodities.

Oil almost doubled in price, from $78.21 in July 2007 for a barrel of benchmark crude, to $145, where it peaked before dipping below $120. But from a longer perspective, oil sold for about $30 a barrel during 2003 and much of 2004. Thus it has actually quadrupled in five years. Coal, traditionally volatile, sold for about $30 a ton during 2003, peaked briefly at $63 in 2004, and went for $45.25 at the end of July 2007. A year later it hit $139.50 before slipping back a bit. It has tripled in 12 months.

Copper, another basic commodity, went from 82¢ a pound in July 2003 to $1.14 a year later, and to $3.72 by the end of last month. That’s an increase of 350% over five years. The price of steel has climbed from under $240 a ton for hot-rolled steel coil throughout most of 2003 to $1,125 a ton last month, quadrupling in five years.

Grains have also soared in price. U.S. corn prices jumped from $3.01 a bushel in July 2007 to $5.37 one year later. Wheat doubled from $3.05 a bushel in July 2006 to $6.02 last month. A Midwestern bakery owned by one of our portfolio companies turns out 13 million pies a year. The cost of ingredients of a standard pie jumped 100%, from $1.20 a year ago to $2.40 today.

The first step in solving the problem is to recognize that we have one—and it is serious. No American housewife has any doubts about that. Our policymakers shouldn’t, either. Yes, Irene, the worse is yet to come.