Before you even start driving that new car to add to your first one, you’ve already burned up three and a half times your annual carbon budget. How? By encouraging the manufacturing of all of those raw materials and metals.
Yet there’s a break-even point at which the carbon savings from driving a new, more efficient car exceeds the carbon cost required to produce it. For example, on average, trading in a 15-mile-per-gallon S.U.V. for a 35-m.p.g. sedan offsets the extra manufacturing costs within two years.
Anything you do to improve mileage will reduce your carbon output. Keeping to the speed limit and driving defensively can improve your mileage by more than 30 percent, according to the Department of Energy. Even something as simple as keeping your tires inflated and having your engine tuned up can give you up to a 7 percent bump in m.p.g. — and an average carbon savings of about what you’d save from eating only local foods all year.