The U.S. Geological Survey has taken a look around the part of the world north of the Arctic Circle, and in a new estimate, out today, it says there are probably "90 billion barrels of undiscovered, technically recoverable oil, 1,670 trillion cubic feet of technically recoverable natural gas, and 44 million barrels of technically recoverable natural gas liquids in 25 geologically defined areas thought to have potential for petroleum." What do those numbers mean? The USGS says it could be 22 percent of the undiscovered petroleum on the planet — 13 percent of the oil and 30 percent of the natural gas. There’s a fact sheet HERE, and more at the USGS Arctic Assessment site HERE. They’ll give more of an idea of how the estimate was made. 84 percent of what could be drilled is probably offshore, says the report. That makes it harder and more expensive to reach — but if indeed more of the Arctic Ocean is more ice-free in summer than it used to be, there are fewer complications than there used to be. (See last year’s report from the National Snow and Ice Data Center; it’s HERE.) One more bit of fodder, perhaps, for the debate about powering the economy in the future. But while 90 billion barrels sound like a lot, the USGS says that’s the equivalent of the world’s demand for about three years.