The two-year anniversary of this column quietly passed a couple of days ago. I didn’t notice until just now. So much for fanfare.

Fungible.

Merriam-Webster’s defines the word: 1. Being of such a nature that one part or quantity may be replaced by another equal part or quantity in the satisfaction of an obligation. 2. Interchangeable.

Oil is fungible. Crude from Venezuela is as good as that from Canada is as good as that from the Middle East. It can all satisfy the hunger pangs of energy dependence that the United States, and the world, have. Bluntly, it’s an international commodity in a global, interconnected market.

That means unrest in the Middle East affects per-barrel oil prices. So do worker strikes in South American countries U.S. citizens haven’t heard off. So does the cost of extracting usable oil from Canadian sand flats.

My thoughts turned again to this word on my drive home from work last night. Regular, 87-octane gasoline had nudged up 15 cents while I worked. That’s on top of a 30-cent jump from about two weeks ago. In three weeks, gas shot from about $2.20 to $2.65 per gallon in my area, and I’m sure other parts of the country have seen the same trend.

Which brings me to today’s word: exposed.

Again, Merriam-Webster’s helps me out: 1. Open to view. 2 Not shielded or protected.

I remember discussions with a close friend, who a few years ago applauded a nasty spike in gas prices at the time. (Now, it’s quaint to complain about gas prices rising to the unheard-of cost of $2 per gallon.) People who buy enormous SUVs for capricious reasons need to understand the consequence, he reasoned. When it costs $100-plus to fill the tank of your monster truck, you’ll think twice about buying another one; in the long run, patterns change.

I disagreed then, but have come around. I have a 4-cylinder Saturn, and pay about $25 to fill it up (maybe closer to $30 after this recent spike). It seems like a lot to me, and I bitch about it, but it makes me more judicious in my use. In the long run, that’s a good thing.

But it’s not enough. During last summer’s spike, I wrote about the ripple effect of gasoline prices on the economy, and tried to put it in perspective. “How different would the U.S. be now if in 1973, or even 1979, when long lines for dry pumps whipped up outrage, long-viewed politicians put in place a plan to wean us from our addiction?,” I wrote.

Uncertain energy costs act as a nail in the foot of the U.S. economy - keeping it from straying too far from the source.

And that addiction isn’t going away. Our economy, our way of life, rotates on an axis of energy dependence. Think about that every time you plug in your mobile phone or iPod. The source of that energy is the only part of the equation that can change.

But first, attitudes must change. The U.S. government has been subsidizing oil drilling in the Gulf of Mexico through tax breaks to the tune of at least $7 billion over the last 11 years alone. (That’s $23 per U.S. citizen, enough to push my gas tank to “F”.) And President Bush’s green initiative should draw all our applause, but it’s price tag pales in light of such subsidies to perpetuate the fossil economy.

Which brings me to tomorrow’s word: withdrawal.

1. The discontinuance of administration or use of a drug. 2. The syndrome of often painful physical and psychological symptoms that follows discontinuance of an addicting drug.

Weaning ourselves onto cleaner, more stable energy sources is going to hurt. Even heroin addicts, I suspect, know deep down that their drug of choice is slowly killing them. Is there the energy equivalent of a methadone clinic?