The main cause behind the unfolding oil glut is not declining demand but rising supply.

The dramatic expansion of shale extraction in the U.S. has been such that Saudi Arabia has effectively lost its main client. With global shale deposits apparently exceeding the equivalent of Saudi Arabia’s entire oil deposits, it was only a matter of time until technology would allow the energy industry to tap into this resource.

Now, hardly two decades after American industry began extracting it, shale accounts for nearly half of U.S. gas consumption, as drilling abounds in Texas and Dakota while the U.S. produces one tenth of the world’s oil and looms as a net exporter of oil. Other countries with great shale deposits, most notably China, will soon follow suit.