The massive economic crisis in Argentina has had an unexpected silver lining for the environment: It has led to a surge in the use of compressed natural gas (CNG) in cars, a cleaner fuel than either diesel or gasoline. Argentina is home to the third-largest natural-gas reserves in Latin America and the world’s largest fleet of natural-gas cars, at about 800,000, or 15 percent of personal vehicles. After the peso was devalued in January 2002, gasoline and diesel prices jumped by more than 30 percent, making CNG the most economical fuel available. “There’s a revolution going on in the energy sector that developed countries aren’t taking notice of. Developed countries are betting on the fuel cell idea, but that’s for some 20 years from now,” said Gregorio Kopyto of Argentina’s Chamber of Compressed Natural Gas. (Enviros will be less thrilled to learn that the Argentinean government has also helped promote CNG use in order to cut costs in public transportation.)