It's an intellectual exercise to even imagine what our lives would look like if oil was no longer cheap and plentiful. Sure, there will always be some in the ground, but when it becomes too expensive to get it out, there will be big changes afoot.

We depend on oil to get us to the store and to get our food and goods there as well. It's a huge component of the industrial agriculture model that feeds most of our country. And petroleum is in just about everything we buy -- from bubble gum to tires to eyeglasses.

And when you consider how oil powers our economy, things look bleak.

"The global-energy equation is changing rapidly, and with it is likely to come great power competition, economic peril, rising starvation, growing unrest, environmental disaster and shrinking energy supplies, no matter what steps are taken," Klare wrote.

Peak-oil prophet James Howard Kunstler, who has written extensively on the subject, echoes his sentiments. In his book The Long Emergency, he cautions: "What is generally not comprehended about this predicament is that the developed world will begin to suffer long before the oil and gas actually run out. The American way of life -- which is now virtually synonymous with suburbia -- can run only on reliable supplies of dependably cheap oil and gas."

And it gets worse in his eyes. "Oil led the human race to a threshold of nearly godlike power to transform the world. It was right there in the ground, easy to get. We used it as if there was no tomorrow. Now there may not be one."