Burning fossil fuels and their derivatives produces, among other things, harmful pollutants such as particulates, acid rain-producing sulfur and nitrogen oxides, and carbon oxides. These air pollutants threaten ecosystems all over the world, and high carbon dioxide levels contribute to global warming. Furthermore, fossils fuels have a limited supply. The market price of fossil fuels, especially crude oil, has continued to rise in recent years. Despite this, Americans continue to consume fossil fuels at alarming rates and rely upon them for most of energy needs. At various times, the federal government has considered mandating higher fuel efficiency standards for American vehicles as a possible solution to this environmental energy crisis. Most auto manufacturers, however, are opposed to the imposition of standards. would oppose fuel efficiency standards because they believe that we will either find more oil or find an alternative solution to the fossil fuel crisis. Cassandras Transcendentalists Cornucopians Preservationists Conservationists