IN the United States, air travel generates as much as 10% of transportation-based emissions of carbon dioxide, the primary greenhouse gas responsible for global warming, according to the U.S. Department of Transportation's Center for Climate Change and Environmental Forecasting. A typical flight from Los Angeles to New York, for example, generates 1 ton of carbon dioxide per passenger.
To spread the word about travel's contribution to global warming, online travel agencies Expedia and Travelocity this month partnered with groups dedicated to decreasing the amount of greenhouse gases released into the environment.
"There is a large contingent of consumers ... concerned with green travel," said Expedia spokeswoman Katie Deines. "It's important to us to offer our customers options in that vein."
Expedia has become partners with TerraPass (www.terrapass.com), a 2-year-old company that sells customers "passes" to help offset the greenhouse-gas emissions caused by their travel.
For a round-trip flight of 6,500 miles (a bit more than a trip from Los Angeles to New York), a TerraPass costs $17; for international flights, $30.
Expedia gives all the money directly to TerraPass, which invests in projects designed to decrease carbon emissions in other industries. It funds clean energy projects throughout the U.S., including wind farms and biomass energy, and the generation of electricity from animal and plant material, such as cow manure.
Methane derived from cow manure has several advantages over fossil fuels, according to TerraPass. It's renewable, which means no net carbon is put into the air, and the process reduces the amount of methane, a greenhouse gas 22 times more potent than carbon dioxide, entering the atmosphere.
TerraPass also purchases something called "carbon offsets" -- which are essentially licenses to pollute -- and retires them.
These carbon offsets are voluntary restrictions on carbon emissions to which businesses nationwide agree. If a business has an excess of them, they can be traded on the free market on the Chicago Climate Exchange. In theory, the fewer licenses on the market, the less pollution.
Such models of greenhouse gas reduction have been around Europe for years but are just catching on in this country.
The U.S. has been "a little bit behind the rest of the world in recognizing the concept," Deines said.
