At the moment, the world remains unsure what deal may yet emerge from negotiations with Iran over its nuclear program. Iran’s R-265 spheroidal three-stage warheads are almost ready to load into Teheran’s Shahab-3 missile nosecones. The Shabab-3 missiles, remonikered from their North Korean origin, are designed to airburst at a height of approximately 650 meters over Tel Aviv replicating the atomic explosion over Hiroshima. To complete the circuit, Iran is only missing the 25 to 27 kg of Highly Enriched Uranium (HEU) — the so-called “significant quantity” — each bomb needs to detonate into a mushroom cloud. That “significant quantity” is, at this moment, being distilled from uranium, gram by gram, in Iran’s long rows of ever-whirring centrifuges. The incremental process relies on intermediate levels of 5 percent and 20 percent, which respectively achieves some 75 percent and 90 percent of the target enrichment, according to nuclear experts.

While the world’s diplomats are focused on the two key fuels, uranium and plutonium, one ancient fuel drives this entire process. That ancient fuel is oil.

Petrodollars have been financing Iran’s nuclear program for almost two decades. So, while the International Atomic Energy Agency is struggling to embed its monitors deep inside Iran’s infrastructure, the average person can help slow the centrifuges simply by reducing their household’s demand for oil.

Even though Iranian oil has been proscribed by international sanctions, all oil is fungible. When oil consumption is measurably reduced in America and elsewhere, it very quickly lowers the value of the global supply. That cheapens the value of Iran’s oil, the financial furnace of its nuclear program.

Iran needs oil to sell at approximately $143 per barrel to maintain its social, governmental, and military programs. But the global glut, combined with the recession and some conservation, have driven recent prices into the high $40s and $50s per barrel. This means that even if sanctions are relaxed and the stealth market expands, Iran will still be hurting at the pump and in the bank.

Unwilling to dismantle its oil export industry and refusing to acknowledge the damage, Iran has been hiding its unsellable surplus in some 15 Very Large Crude Carriers (VLCCs) lurking off Bandar Abbas, Assaluyeh’s South Pars Terminal, Kharg Island, and elsewhere at sea. Each VLCC is carrying about 2 million barrels, perhaps more, based on the hull’s water level observed by a consensus of oil shipping experts. These ships have floated like seaborne warehouses for more than a year, and many suggest more than two years. Some have been reflagged or renamed to avoid detection, but giant tankers are hardly invisible. In the meantime, Iran has cut its output from a pre-sanction 2012 level of 2.5 million per day to just over one million today.

Oil impoverishment is the only reason Iran is now negotiating on its uranium enrichment. The two are linked.

In any international accord, it would take Iran some time to recover from its oil glut, especially with millions of barrels at sea waiting for customers. The floating oil reserves would go first.

Average people can make that recovery more difficult without buying an electric car, peddling a bicycle to work, or cancelling a road trip. Most gasoline today contains 10 percent ethanol, an alcohol fuel derived from corn and other crops. The recent Hollywood documentary Pump, in which I made a brief appearance along with numerous other oil addiction experts, revealed most modern motor vehicles can accept E-85, that is, up to 85 percent ethanol with a simple software update — in some cases a single click, automotive engineers explain. More compelling, Pump demonstrates how more than 9 million American flex-fuel automobiles, the ones with a yellow gas cap, are already built to accept E-85. Transportation accounts for two-thirds of all US petroleum use. This one software click could reduce and drastically cut oil consumption overnight if ethanol supply would rise commensurately.

The engineers in the Pump documentary demonstrated that the software update process takes only a few minutes. Pump has long ago left the movie theaters, and is now available from online outlets. If government and commercial fleet managers, as well as ordinary consumers, see how easy it is to switch, America could be swept by a sea-change reduction in our dependence on foreign oil. Then regardless of what the nuclear negotiators and inspectors do, average people could help permanently drive the outcome.

Edwin Black is the New York Times bestselling author of IBM and the Holocaust, and numerous several on oil, including British Petroleum and the Redline Agreement and Internal Combustion.