Sunday, February 18, 2007

Problems with Carbon Calculators

Twana and I were talking about our carbon footprint today. She couldn't believe it was as large as I said it was. I gave her the numbers I'd used in the Rotary presentation two weeks ago, and when she plugged them into the carbon calculator at The Climate Crisis web site, she got lower numbers than I had gotten from Acterra's calculator.

"OK," I thought, "this should be easy to settle. If two calculators are different, I should just be able to go to a third calculator and it would agree with one or the other of the first two."

No such luck! I spent a couple of hours checking out 7 different calculators, and there is far less consensus than there should be. I found at least two cases where there were discrepancies between the footnotes in "How we calculated the numbers" and the actual results that showed up on the screen. I'm very frustrated by this. If one of the goals of environmentalists is to cut CO2 production -- and it is -- we need to understand where to invest and how to change our behavior to do this effectively.

To give you an extreme example of how bad the discrepanices are, the Bonneville Education Foundation's calculator says that 10,000 kWh of electricity produced in California generates 3,264 pounds of CO2. But the Carboncounter.org's calculator says it produces 7,300 pounds.

The divergence for CO2 created by air travel was similarly large.

Grrr!

My conclusion is that Acterra's calculator is the best one that I was able to find, and it does a really good job of explaining how it comes up with the results it presents. So, I've included a link to it on the right-hand side of this blog.

No comments: