It's a legitimate question: by flying me out to Denver and driving me around the state for much of the day, did National Geographic TV end up substantially compounding the very problem I talk about with the cheeseburger footprint story?

Let's do the math. According to Terrapass, my flight out to Denver and back ran about 867 pounds of CO2, total (per passenger). In the course of filming in a variety of locations, we drove two vehicles -- a standard pickup truck and a minivan, carrying a sum of six people and a huge amount of gear -- about 250 miles apiece. According to EPA estimates, pickups and minivans of appropriate size and vintage emit anywhere from 8 to 12 tons of CO2 over the course of driving 15,000 miles; call it 10 tons for easy math. 20,000 pounds of CO2 for 15,000 miles equals 1.3 pounds per mile, so 500 miles equals 666.7 pounds of CO2. That brings us to 1533.7 pounds for transportation alone; add in the incidentals of the day (power to charge the camera batteries, meals, and such), and we can reasonably estimate 1,600 pounds of direct CO2 emissions as the result of the day's activities.

Or, to put that into more familiar terms, that's about 160 cheeseburgers, a bit more than the average American's annual consumption.

Was it worth doing? I think so. I wouldn't have done it if I hadn't thought the costs were worthwhile. Shows like Six Degrees get more viewers even on a lousy night than have ever read the Cheeseburger Footprint post, or have seen its various appearances in the blogosphere. Clearly, the meme is a good one -- I apparently stumbled across the right combination of cultural icon and environmental provocation -- and I'm still getting press inquiries about it. I expect that, when the show comes out in February, I'll get another flurry of emails. Depending upon how the material is presented, it may even end up as the hook used in promos and criticized in reviews.

Having worked in the TV industry for a couple of years in the late 1990s, I was sufficiently familiar with the sausage-making that goes into filming a TV show that I wasn't surprised by much of the NGTV day. Incessant retakes, technical flubs, material shot that would likely never even be considered for use, and the knowledge that at least six hours of filming would result in 3 minutes of screen time -- none of these were alien to me.

What I did find distressing was the nagging sense that I never really told the story right, that I had left off important parts, or that in the course of speaking extemporaneously about the subject, I'd messed up some numbers. I don't mind looking goofy for the show, I just don't want to come across as a fool.