"According to the National Academy of Sciences, the Earth's surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is new and stronger evidence that most of the warming over the last 50 years is attributable to human activities. Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how earth’s climate responds to them. Since the beginning of the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%." Nuff said! http://yosemite.epa.gov/oar/globalwa...ent/index.html
Plus, I know for a fact that Honda and Toyota are both taking steps to produce low-emmision vehicles. For example, the Toyota Prius is a hybrid car already on the market and it's only about $20,000 and the 2005 Honda Accord Hybrid, although it costs about $30,000, is still available. And those prices are still extremely cheap for a car.