Making a carbon dioxide-offsetting donation

CO2 offsets seller TerraPass has announced a partnership with Expedia, one of the web's top travel sites, to offer Flight Terrapasses to Expedia customers when they book their flights. The co-marketed Flight TerraPass comes at three purchase levels: 1,000 lbs of CO2 for $5.99; 2,500 lbs of CO2 for $16.99; and 5,000 lbs of CO2 for $29.99, enough to balance about 2,200 miles; 6,500 miles; and 13,000 miles of flying, respectively.

• To buy a Flight TerraPass through Expedia, just book a ticket as you normally would, and look for TerraPass on the “Customize your trip” page under the heading of “Featured Activities & Services.” You can also buy a TerraPass through Expedia separately from your plane ticket by clicking on the “Activities” tab and selecting dates and a destination.

• See Carbon offsets and treehugger comments for criticism of this scheme.