Oil’s decline is proving to be the worst since the collapse of the financial system in 2008 and threatening to have the same global impact of falling prices three decades ago that led to the Mexican debt crisis and the end of the Soviet Union.

Russia, the world’s largest producer, can no longer rely on the same oil revenues to rescue an economy suffering from European and U.S. sanctions. Iran, also reeling from similar sanctions, will need to reduce subsidies that have partly insulated its growing population. Nigeria, fighting an Islamic insurgency, and Venezuela, crippled by failing political and economic policies, also rank among the biggest losers from the decision by the Organization of Petroleum Exporting Countries last week to let the force of the market determine what some experts say will be the first free fall in decades.

“This is a big shock in Caracas, it’s a shock in Tehran, it’s a shock in Abuja,” Daniel Yergin, vice chairman of Englewood, Colorado-based consultant IHS Inc. and author of a Pulitzer Prize-winning history of oil, told Bloomberg Radio. “There’s a change in psychology. There’s going to be a higher degree of uncertainty.” 

A world already unsettled by Russian-inspired insurrection in Ukraine to the onslaught of Islamic State in the Middle East is about be roiled further as crude prices plunge. Global energy markets have been upended by an unprecedented North American oil boom brought on by hydraulic fracturing, the process of blasting shale rocks to release oil and gas.

Few expected the extent or speed of the U.S. oil resurgence. As wildcatters unlocked new energy supplies, some oil exporters abroad failed to invest in diversifying their economies. Coddled by years of $100 crude, governments instead spent that windfall subsidizing everything from 5 cents-per-gallon gasoline to cheap housing that kept a growing population of underemployed citizens content.

Those handouts are now at risk.

“If the governments aren’t able to spend to keep the kids off the streets they will go back to the streets, and we could start to see political disruption and upheaval,” said Paul Stevens, distinguished fellow for energy, environment and resources at Chatham House in London, a U.K. policy group. “The majority of members of OPEC need well over $100 a barrel to balance their budgets. If they start cutting expenditure, this is likely to cause problems.”

Oil has dropped 37 percent this year and, in theory, production can continue to flow until prices fall below the day-to-day costs at existing wells. Stevens said some U.S. shale producers may break even at $40 a barrel or less. The International Energy Agency estimates most drilling in the Bakken formation ― the shale producers that OPEC seeks to drive out of business ― return cash at $42 a barrel.

“Right now we’re seeing a price shock coming out of the meeting and it will be a couple of weeks until we see where the price really falls,” said Yergin. Officials “have to figure out where the new price range is, and that’s the drama that’s going to play out in the weeks ahead.”

Brent crude finished last week around $70, and New York oil near $66. Brent is now at its lowest since the financial crisis ― when it bottomed around $36. (Bloomberg)