To meet the world's boundless thirst for oil, drillers are searching in the sand and mud of remote western Canada, the tough shale rock of North Dakota and more than a mile under the seas off the southern U.S. coast, where a drilling accident has sent hundreds of thousands of gallons of crude spewing into the Gulf of Mexico.
Why are we going nearly to the ends of the earth and the bottom of the seas for oil?
The answer, say many experts, is that we're consuming as much oil as we ever have but the era of "easy oil" is in our rearview mirror and receding fast.
Production from onshore oilfields in the U.S. has been declining since the 1970s, and near-shore production along the Gulf of Mexico peaked more than a decade ago. Many of the richest remaining conventional deposits are in places that are politically unstable, such as Iraq and Nigeria, or hostile to Western oil companies, such as Sudan, Venezuela and the Middle East.
While Americans remain tethered to a petro-driven economy and surging demand from China and other emerging markets is driving up global demand, the quest for new sources requires more money and technological wizardry than ever before. As anyone tracking the massive gulf spill can attest, it brings greater risks as well.