How Accurate are Carbon Calculators?
By KATE WILLSON
Observer Staff
Oct. 18, 2007
I don’t own a car. I flick off the lights when I leave a room, and use compact fluorescent lights when I need them. I fly home to Oregon about once a year. Living so “green,” I was surprised to learn that when I plug my energy-usage into An Inconvenient Truth’s carbon calculator, I still produce an estimated 4.4 tons of carbon a year.
That’s on par with the average global citizen, although I’m proud to say that’s one-fourth the annual carbon emissions for the average U.S. resident.
But the calculator didn’t ask me about whether I drink bottled water (the packaging and bottling process requires carbon) or ask for plastic bags at the grocery (also uses carbon to produce) instead of bringing my own cloth alternative.
I just plugged in my digits and it spat out my tonnage, then directed me to Native Energy’s carbon offset site
where I learned I could pay $4 a month to live “Carbon-free.” If I cancel that trip home for Christmas, my tonnage would drop to one-ton and my monthly fee to $1.
Can I really live guilt-free for $12 a year? Are these calculators reliable?
Most, including Native Energy’s Web site, factor in car and air travel, and home utilities. Many also ask whether you receive any percentage of electricity from a renewable resource. Pepco doesn’t give Washington residents that option, though.
The calculators “give you a general sense of what your emissions look like,” said Samantha Putt del Pino, who built the Safe Climate Calculator at the World Resources Institute.
Putt del Pino said that energy-use snapshot gets clearer for users who re-enter their data every month, tracking fluctuations during the coldest and hottest months of the year. She said the WRI provides the calculator but doesn’t say whether a consumer should pay to offset their carbon use with one of the many firms that invest in renewable energy or carbon sequestration.
But if you’re interested in comparing calculations, here are two more tried-and-trusted calculators:
