When it comes to cars and the environment, bigger is never better! Next time you're ready to buy or lease, go small and lessen the damage your driving does to the environment. The carbon emissions from the cars we drive are some of the biggest contributors to global warming and air pollution. More than half of a 2-car family's carbon emissions come from the vehicles they drive, according to the Inter Press Service. Despite the rise of the SUV, fuel economy is now a crucial factor in car purchasing decisions.