Flying round-trip from Seattle to San Francisco releases more than 600 pounds of CO2 per passenger. In only a few hours, that trip emits more carbon than if every passenger drove his own car from Seattle to Spokane and back!

But obligations and loved ones are often far from Washington. This year, make your holiday travel a little greener with these tips:

Take the train: If your trip is short, consider Amtrak. A train trip from Seattle to SF releases only 119 pounds of CO2 per passenger.

Go non-stop: Choose one long flight instead of multiple short ones. Flights shorter than 250 miles emit about 40% more carbon per mile than flights longer than 800 miles.

Fly by day: During the day, white trails of condensation from aircraft reflect the sun's energy back into space. But at night they trap the heat, adding to the greenhouse effect.  

Use public transit: Take the bus or a van share to and from the airport.

Offset your flight: Although there is no way to reverse your flight's impact, you can offset the carbon emissions of your trip by purchasing carbon credits. The sale of carbon credits funds projects that prevent or reduce carbon emissions elsewhere. TerraPass, for example, supports wind energy farms and Carbon Fund supports various renewable energy projects.

Learn more about the public transportation options available to and from the airport here. Find more information here to help you choose a carbon offset company.