Daniel Yergin:

Forty years ago, on Oct. 17, 1973, the world experienced its first “oil shock” as Arab exporters declared an embargo on shipments to Western countries. The OPEC embargo was prompted by America’s military support for Israel, which was repelling a coordinated surprise attack by Arab countries that had begun on Oct. 6, the sacred Jewish holiday of Yom Kippur.

With prices quadrupling in the next few months, the oil crisis set off an upheaval in global politics and the world economy. It also challenged America’s position in the world, polarized its politics at home and shook the country’s confidence.

Yet the crisis meant even more because it was the birth of the modern era of energy. Although the OPEC embargo seemed to provide proof that the world was running short of oil resources, the move by Arab exporters did the opposite: It provided massive incentive to develop new oil fields outside of the Middle East—what became known as “non-OPEC,” led by drilling in the North Sea and Alaska.

The Prudhoe Bay oil field was discovered in Alaska five years before the crisis. Yet opposition by environmentalists had prevented approval for a pipeline to bring the oil down from the North Slope—very much a “prequel” to the current battle over the Keystone XL pipeline. Only in the immediate aftermath of the embargo did a shaken Congress approve a pipeline that eventually added at its peak as much as two million barrels a day to the domestic supply.