Car Emissions and Global Warming
We are driving up the planet’s temperature. Transportation is one of the primary contributors to global warming, generating more than one-third of all U.S. carbon dioxide emissions and 30 percent of America’s total global warming emissions. If we are going to effectively address global warming, we must reduce the emissions our vehicles produce.
The Earth is warming and human activity is the primary cause.
Climate disruptions caused by global warming put our food and water supply at risk, endanger our health, jeopardize our national security, and threaten other basic human needs. Some impacts—such as record high temperatures, melting glaciers, and severe flooding and droughts—are already increasingly common.
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Sources of Transportation Heat-Trapping Emissions (2005) |
More than 60 percent of U.S. transportation emissions come from cars and light trucks.
Passenger cars and light trucks represent the lion’s share of U.S. transportation emissions and collectively produce more than one-fifth of the nation’s total global warming pollution. The remaining transportation emissions come from medium and heavy-duty vehicles (primarily freight trucks and buses), plus aircraft, shipping, rail, military, and other uses.
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Cars and Trucks and Global Warming
1 gallon of gas = 25 pounds of global warming emissions
Every gallon of gas burned emits nearly 25 pounds of carbon dioxide and other global-warming gases into the atmosphere. About 5 pounds of that come from the extraction of petroleum and the production and delivery of the fuel. But the great bulk of heat-trapping emissions—more than 19 pounds per gallon—comes right out of a car’s tailpipe. It adds up fast. Each year, the average car sends 7 tons of carbon dioxide into the atmosphere—about three and a half times the vehicle’s weight.
We can go the distance—and produce fewer emissions along the way.
Fuel-efficient vehicles use less gas to travel the same distance as their less efficient counterparts. When we burn less fuel, we generate fewer emissions. When emissions go down, the pace of global warming slows. Current, affordable, clean vehicle technology can significantly increase the fuel economy of our nation’s cars and trucks today and lessen the global warming impact of our transportation choices. Advanced vehicle technologies offer the promise of even greater efficiency in the decades ahead.
Biofuels can further reduce emissions.
Biofuels are made from organic materials like corn, grass, and agricultural waste and have the potential to provide more than 10 percent of U.S. fuel needs. Biofuels can produce fewer global warming emissions than conventional gasoline, though the amount varies considerably depending on the source material and production methods used to create it. Corn-based ethanol is one of the least effective biofuels at reducing emissions; advanced biofuels made from grass, wood waste, and even garbage offer much greater savings.
