Dwindling stockpiles of diesel have driven prices to a record premium over gasoline and crude oil, showing how war, weather and other disruptions to globalized energy markets are still producing price shocks and potential shortages.

While the price of gasoline is up about 14% this year, diesel has climbed about 50%, to $5.35 a gallon, according to AAA/Opis. The gains widened the gap between the two to an all-time high of $1.61. A year ago, it was 23 cents. Wholesale diesel, delivered into New York harbor, traded at a record premium to crude oil in October, according to the Energy Information Administration, which also reported the country had only 25 days of diesel in reserve, the lowest since 2008.

Diesel, like gasoline, is refined from crude oil and is the fuel of choice for most of the engines in farm and manufacturing equipment, as well as the trucks and trains that transport the country’s goods. Its price at the pump includes those refining costs, which often vary with the price of the natural gas used in the process.

A major driver of the dearth is the war in Ukraine. Russia’s exports of diesel have been more interrupted than those of its crude. The country’s curtailment of natural-gas flows to Europe has also lifted refining costs there, while pushing end users such as power plants to switch from gas to diesel.