This spring, San Francisco International Airport will allow fliers to feel better about their gas-guzzling plane trips with certified carbon offsets available at airport kiosks.

The program will be jointly led by SFO and 3Degrees, a firm that sells renewable energy and carbon reduction investments. Thus far, SFO has invested $16,000 in the kiosks.

According to airport officials, the carbon offset kiosks will allow passengers to input a destination into a computer that calculates both the trip's carbon footprint and the investment necessary to offset it. A credit card swipe will let travelers erase their guilt, and a printed receipt will act as proof of the good deed.

Details on the carbon offsets' cost to consumers are still fuzzy, but 3Degrees estimates that a trip to Europe will cost approximately $36. 

A similar program that was recently proposed by Denver International Airport is on hold due to lack of interest from vendors.

But with fliers already wary of checked luggage fees, there is plenty of reason to doubt that anyone will want to pile on more expenses—even in environmentally-conscious San Francisco.