Who's right? Neither, really. Obama is talking about oil we know is there. Republicans are talking about oil we think is there.The president likes to refer to our so-called "proven" reserves -- oil that can be recovered with relative certainty given today's economic, technological, and regulatory constraints. It's oil that companies have already discovered, and that they can drill up profitably without breaking the law. Oil in areas where drilling is banned, such as the Arctic National Wildlife Refuge, isn't included. According to the U.S. Energy Information Administration's most recent estimates, the United States has roughly 20 billion barrels of these reserves, around 2 percent of the global total. But proven reserves are only a small part of the petroleum picture, and don't give us a very accurate picture of future supply.
Now, here's where the USGS figures really fall short: They ignore a massive chunk of the world's oil potential future resources. The study looks at conventional oil. That's regular old black gold, the kind that made Jed Clampett and that nutjob from There Will Be Blood rich. But there are many other kinds of oil, which get lumped into a category called "unconventional oil." That includes the billions of barrels of tar sands oil in Canada, heavy oil in Venezuela, and shale oil in North Dakota.*
So Obama's numbers almost certainly underestimate the relative size of America's potential oil supply. The Republicans may be overestimating it. Or, depending on the kinds of unconventional oil discoveries we make in the coming years, they could be massively underestimating it too. But both sides are are oversimplifying the issue. Shocking, I know.