Say you buy a round-trip ticket to fly from Los Angeles to New York for a family reunion. After you book the ticket, you head over to a site like MyClimate, which has a built-in carbon calculator. After entering your departure and destination airports, the calculator tells you how much carbon you need to offset the flight. In this case, it's $23 worth. Most carbon calculators work in this user-friendly way, though prices will vary.
Because there isn't a consensus among travel providers, environmental experts, or carbon-offset retailers themselves, the best course of action for concerned consumers at this point is to proceed with caution. As President of Sustainable Travel International (STI) Brian Mullis points out, "This is still an unregulated industry, and there are both high- and low-quality carbon retailers." Mullis recommends, from his organization's own website, a list of retailers and key factors to take into account when choosing a program. Such factors include cost efficiency, credibility, and transparency. Mullis also cites the Gold Standard as one of the most credible certification programs in the world. The Tufts Climate Initiative is another excellent source for program recommendations and company reviews. Its list of top providers includes some of the same companies STI lists, such as MyClimate and NativeEnergy. Tufts also publishes reviews of more retailers and openly states criticism of those it deems less effective.