Extent of global oil reserves a matter of some dispute

Even as the world’s thirst for oil grows, no one quite knows how much of the precious liquid we have.

Some experts say that the Earth’s oil reserves are smaller than we think. For example, Saudi Arabia, the global economy’s gas tank, might not have the vast petroleum reserves its leaders claim, according to a new book rattling the energy industry. Royal Dutch/ Shell Group last year admitted overstating its oil reserves by about 25 percent.