Tallying Greenhouse Gases From Cars
A new look at ways we can downshift heat-trapping emissions
Posted: 22-Jun-2006; Updated: 07-Sep-2007
The U.S. has 30% of the world's cars, but they account for 45% of global automotive CO2 emissions.
Download report
Driving tips
Did you know that idling for more than ten seconds uses more gas and creates more pollution than simply restarting your engine? If you are stopping for more than ten seconds—except in traffic—turn off your engine.
Ah, the time-honored ritual of road-tripping. Who hasn't enjoyed loading skis, boots and poles into the car, packing your most cherished CDs and cruising backroads to a nearby peak? Or maybe you prefer gathering your blanket, ball and suntan lotion and heading to the shore. Whatever your destination and no matter how much you love driving, there are a couple of hazards difficult to avoid: traffic jams--and the less visible but very serious global warming pollution belching from tailpipes.
How much do American cars contribute to heat-trapping emissions?
A staggering amount of global warming pollution comes from U.S. cars. Our new report Global Warming on the Road [PDF] shows that in 2004, our carbon dioxide (CO2) emissions from personal vehicles totaled 314 million metric tons. That’s equal to the amount of carbon in a coal train 55,000 miles long, enough to circle the world twice. General Motors cars alone account for more carbon pollution than that from America’s largest electric-generating company, American Electric Power. Emissions from Toyota vehicles, fourth among car companies, edge out those from the Tennessee Valley Authority, third among power companies.
We might not picture creating pounds of global warming pollution when we drive, but the exhaust coming out of our car has actual weight—an average household with two mid-sized vehicles emits more than 20,000 pounds of CO2 a year. That's 10 tons of pollution adding to the layer of greenhouse gases that heat the Earth. Excessive amounts of these gases—especially CO2—are forming too thick a heat blanket around the Earth and leading to climate change.
Applying the brakes to global warming pollution
If there’s a silver lining to our massive exhaust cloud, it’s knowledge. Since we know what is contributing to the problem, we also know some solutions. As the report points out, three factors lead to heat-trapping emissions from automobiles:
- amount of driving
- fuel economy and
- the carbon content of the gas used.
Drivers can control two of these. We can streamline the trips we take in our car, cutting down our global warming pollution and saving at the pump. Get more driving tips here. We can also choose vehicles with high fuel economy.
Today's cars matter down the road
One of the most eye-opening findings of the report is that the cars we choose today will affect our lives for decades. Surprisingly, the biggest category of current on-the-road polluters is the small car. Why? Simply because there are so many of them on the road. But soon the much less efficient SUV will become the representative vehicle, and because of its low average fuel economy, the global warming pollution from America’s roadways will surge.
Acting now is imperative to slowing global warming and curbing air pollution. For instance, doubling the fuel efficiency of all new vehicles today would not fully be reflected until 2025. Because cars last so long, seemingly small differences add up to large ones over a car’s lifetime. So drive smart to save fuel and cut global warming pollution, and maintain your car properly so it always runs with peak efficiency. For how to get the most fuel-efficient car that fits your needs and budget, see our car buying guide.
