calculating your carbon hoofprint

In Planet Slayer’s carbon calculator, you start out as a pig. A pig with a charming face and long eyelashes, but a pig all the same. A dog in a white lab coat named Prof. Schpinkee is watching over you with arms crossed, ready to help you figure out how big a greenhouse hog you are, and the best you can hope for is to be an “environmentally sustainable ‘green’ pig.”
Planet Slayer’s may be the least forgiving, but it’s just one of many carbon calculators available online. Tallying your footprint is the logical first step toward reducing your impact or “offsetting” your emissions with purchased carbon credits, and conservation groups, oil companies, and government agencies are all offering their own versions.
But figuring out how much carbon you spew is not easy, and not all calculators are created equal. I tested six – by the Environmental Protection Agency, The Nature Conservancy, BP, Conservation International, ClimateCrisis.net (Al Gore’s thing), and Planet Slayer (a project of the Australian Broadcasting Corp.) – and offer my unscientific review here.
The first thing to recognize is that carbon calculators don’t all calculate the same thing. The one on ClimateCrisis.net seems to be limited to home energy use and transportation. It lists the national average for per-capita emissions as 7.5 tons, which is nowhere near our full greenhouse gas footprint. Likewise, the EPA’s calculator is limited to emissions from home energy use, driving, and waste disposal. Conservation International’s and BP’s are limited to home energy use and transportation, including driving and flying.
Only The Nature Conservancy and Planet Slayer attempt to capture total emissions, or all the emissions “your choices create each year,” as TNC puts it. In the U.S., that’s something like 24 tons (22 if you just look at CO2 or 26 if you include the carbon dioxide equivalent from methane). At least that’s what you get if you divide total U.S. emissions by the number of Americans, which probably wouldn’t include the carbon impact of, say, a TV made in Japan and sold in the U.S.
Carbon calculators are by necessity crude tools. They generally factor in things like how much you drive, how you heat your home, how many people you share your house with, and so on. Your carbon count can start from zero and build as you go or start with an average and shift up or down depending on your energy choices. For everything else – if it’s included at all – carbon calculators generally just plug in a figure based on your country or state’s average. That is, they don’t try to tally up the carbon associated with every iPod, health insurance plan, and public library.
All calculators make the point that you can reduce your footprint by changing how you live, and they try to educate as they count. If you recycle everything, EPA’s calculator takes about 400 pounds of CO2 off your tab. If you eat a lot of meat, TNC’s calculator tacks on a few extra tons. Understanding the impact of those choices is simply a matter of watching the numbers in the right hand column go up or down.
That said, some calculators are more explicit than others. BP’s, for instance, offers direct lessons from a man with green hair, as he sips coffee at home or installs a solar panel on a roof in hardhat and sweater vest. “Compared to a car, public transportation can be a more efficient way of using energy to move people around,” he says as he walks through an airport.
Where most calculators fail, IMHO, is in areas where carbon impacts are harder to quantify. Direct energy consumption is pretty easy, even if some big assumptions are involved – driving a car that gets so many miles per gallon so many miles a year will burn a certain amount of gas and produce a certain amount of CO2. Ditto with flying, home heating, and electricity.
But the carbon behind everything else is harder to figure. Most calculators don’t even try, and rely instead on those big averages. The one that doesn’t is Planet Slayer, which makes the point that there’s carbon behind almost everything we buy and do. One question in its calculator asks, “How much money did you spend all up last year?” Answer less than $10,000 and you, the pig in the trailer, shrink to smaller than the average Aussie pig. Choose $40,000 and you get some extra rolls of belly fat. Pick $70,000 and you turn into a slobbering, snotty swine who can’t keep his gut off the floor.
Planet Slayer explains in the fine print that it’s assuming there’s 1.6 kilograms of CO2, on average, behind every Australian dollar you spend. And that your driving, household energy use, and eating habits account for less than 20 percent of your overall emissions. “The thing that makes a real difference to your bacon-ness is how you SPEND the rest of your money,” it explains.
This expands the common dialogue over carbon footprints from simple things like what we drive and what kind of light bulbs we have to what we eat and what we do for fun. It also leads to some unexpected assertions, like the one that taking a cab is less polluting than riding a bike. “Not really, but because we pay so much to ride in taxis ($1/km), it leaves us less money to spend on stuff that’s even worse for the environment.”
Even if the U.S. economy is more efficient than Australia’s (just guessing here), the idea of a pint of oil behind every dollar is important. When you imagine downing a cup of oil with every cup of OJ, that juice starts to seem less appealing.
Planet Slayer lets you clean up your act by spending on “stuff that’s better for the environment,” like energy-efficient and second-hand items, rather than “ordinary stuff,” like eating, drinking, and going out. The implied lesson isn’t spend less so much as spend wisely.
Partly I blame us media for ignoring this concept. But it also seems like a bit of a third rail for green groups and politicians, even those serious about reducing emissions. Suggesting that people need to buy less stuff is not really going to fly. The effort, justifiably I suppose, has been to reduce the carbon in our economy rather than shrink the economy itself.
In any case, focusing on home energy use, transportation, food, and waste is probably a good start, and complex enough. I tried out the six calculators on my own life and got a wide range of answers. Each calculator asked for different inputs, and none really fit my Alaska lifestyle (living in a dry cabin, eating my own food); Gore’s calculator, which allows you to input the year and make of your car, also mysteriously omitted Toyota’s 1997 line of vehicles. That said, I tried to be consistent with my inputs.
Here’s what I got.
EPA: 12.9 tons (home energy and driving)
Climatecrisis.net: 15.3 tons (home energy and transportation)
Conservation International: 18.3 tons (home energy and transportation)
BP: 12.5 tons (home energy and transportation)
Planet Slayer: 31.9 tons (everything)
The Nature Conservancy: 43 tons (everything)
TNC’s 43 tons is a pretty strong indictment. And according to Planet Slayer, I used up my sustainable share of the planet’s resources in 7.9 years. I think I was unfairly billed for heating and electric costs, and I don’t spend that much money on “ordinary stuff,” but I'm definitely no green pig.