On average, every American is responsible for about 22 tons of carbon-dioxide emissions per year. That’s equivalent to the emissions of about 4 cars.

It's actually about 26.5 tons as of 2004, before accounting for sinks (which drops it to about 23.7 tons), and since the average US car puts out about 5.5 tons of CO2 a year, it's equivalent to roughly 5 cars.

The numbers are a bit deceptive, since individuals are directly responsible for only about 41% of energy consumption (residential plus at most 68% of transportation). So it's probably more accurate to say per capita emissions are closer to 11 tons.

The quickest and biggest way to reduce that footprint is to sign up for carbon-neutral power from your utility (if possible). Next is to either curtail your driving, get a more efficient vehicle, change to a more carbon-neutral fuel (like biodiesel or ethanol).

Call me when the billions of people living in India and China are part of your Green Challenge. Until then, I'm getting in my SUV, driving three blocks to the grocery store, loading up on meat and processed food, and leaving on all the lights, the TV AND two computer monitors while I'm gone.

I read the transportation file. It is positive and informative. Thank you for informing me of this article series. I look forward to the next one.

"Until then, I'm getting in my SUV, driving three blocks to the grocery store, loading up on meat and processed food, and leaving on all the lights, the TV AND two computer monitors while I'm gone."

So you are a sheep? Until others do it, you won't? And you don't think that China and India are very aware of what they have to do? Sad.

So, um, the quiz doesn't work in Safari, and when I took it using FireFox, it tells me at the end:
"Your annual carbon emissions are lbs."
So, I realize that I am a pretty efficient person, but I think I probably emit some number of pounds annually.

Until then, I'm getting in my SUV, driving three blocks to the grocery store, loading up on meat and processed food, and leaving on all the lights, the TV AND two computer monitors while I'm gone.

Trolls don't leave from under the bridge. You're fooling no one.

Only trolls feed trolls...which I guess this is too.

I tried to do the quiz and it timed out in less than 5 minutes. And it didn't tell me what I needed to fill completely. Not exactly good. Who makes this stuff?

So, transportation to work doesn't include bike commuting or walking? And what do I check if I don't have a dishwasher?

Hey this massively sucks. I use bus, bicycle, or running shoes to get almost every where. What about that. I mean this is a poor excuse for a carbon calculator.

this is great and right in line with my own personal green challenge...but i'm having problems with the quiz. i even registered. i guess i'll try again later :(

I live in Oregon and I burn wood, I found the heating aspect a little biased toward the East Coast. I was hoping to take the quiz. Oh well.

Not working for me either - I got (blank) lbs...

Will the all the quizzes be available after the eight weeks are up? We've started a local group to deal with clean energy issues, and people might be interested in trying to do this socially, but we wouldn't be able to get started for a while yet.

The quiz doesn't take into account carsharing or car rentals - I don't own a car, but I do drive... as do plenty of other city folk around here.

from the Slate post:

Transportation is one of the biggest culprits in human production of carbon dioxide—the source of about one-fifth of global-warming emissions worldwide.

It's 16.5% excluding land-use changes and forestry (LUCF aka "sinks") and 13.5% including it.

In the United States, two-thirds of the oil consumed goes toward powering vehicles.

Toward the transportation sector, yes, that's correct.

Passenger cars alone are responsible for 25 percent of the greenhouse gases we produce.

Passenger cars account for 8.9% of our gross emissions and 10.0% of our net emissions (the US is one of the few countries where LUCF numbers are negative).

Today's passenger cars average just 24 miles per gallon, the lowest level since 1980.

Cars in the US as a whole average 22.3 mpg as of 2003 and averaged 15.9 mpg in 1980. New cars in 2005 rated an average 28.9 mpg, compared to 23.5 mpg in 1980.

Ford's Model T got 28.5 miles per gallon

No one really knows what it got, but it had a top speed of 45 mph, no seat belts, and no emissions control system. It's really not comparable to modern vehicles.

For each gallon of gas your car burns, it releases about 19 pounds of carbon dioxide.

True, gasoline creates 19.564 lbs of CO2 per gallon combusted.

So, if you could tweak your ride to eke out just three extra miles per gallon, you'd save about 1,000 pounds of CO2 emissions a year, based on an average mileage of 12,000 a year.

Given your assumption, that's true. Of course, the higher the fuel economy baseline, the less an extra 3 mpg matters in terms of reducing emissions.

Then there's air travel: It costs 100 gallons of fuel per passenger to go coast to coast.

The average domestic flight gets 37.6 passenger-miles per gallon. Generally, longer flights (eg, LAX to LaGuardia) will have higher than average fuel economy (better amortising the energy-intensive liftoff fuel consumption). But even at average numbers, a flight from LAX to LaGuardia will require 66 gallons of jet fuel per passenger.

DON'T DRIVE--ONE DAY A WEEK, 50 days a year. Think of the cascade of good effects: save gas and oil; save on car upkeep; less pollution; less congestion; prevent accidents; less road rage; and, if there's enough participation, the price of gas will drop (due to less demand) and perhaps a petrol-dictator or two would topple. This idea costs nothing, is purely voluntary, demands no sacrifice, and involves only minor inconvenience, one day a week.

I too get lbs. Also we have a heat pump which runs on electricity. Not everyone heats with oil or gas.

Slate has a glitch. Many of us cannot login to the quiz.

Hi everyone:

Meaghan(at) TreeHugger here. Let me begin by telling you that the kinks have all been worked out of the quiz, so if you were discouraged before by a few bugs in the system, please try again. Sorry for the inconvenience and thanks for your interest in the first place.

Now, on to a word about figures. For those of you who’ve been scouring the Internet to back up—or disclaim—the numbers and facts you see included in the Challenge, let me say a word or two: First, thank you for fact-checking our work; that’s what keeps us honest, so to speak, and motivates us to get it right in the first place. Second, if you’ve been digging around to research statistics on global warming and carbon emissions, especially as pertains to individuals, then surely you’ve noticed that they differ widely from agency to agency. This is because science is not perfect, and because different organizations are using not only different numbers but also different assumptions to arrive at various calculations. For these reasons, one organization (in this case the United Nations) claims that each American is responsible for an average of 22 tons of carbon dioxide being emitted into the atmosphere each year. Another organization may say 26.2; yet another 30. Each would then arrive at a slightly different calculation for how many cars’ emissions that is equivalent to, especially considering that the average miles per gallon an average car gets—or how many miles an average person drives in a year—will also be different. (See where this gets complicated? In the case of our Transportation segment, we relied on figures from the EPA and NRDC.) We have tried very, very hard in every instance to use sources that we trust and numbers that seem reasonable. Ultimately, it’s not about getting the figures exactly right on—we know that any carbon footprint quiz cannot accurately tabulate the exact emissions that any one individual is responsible for—but we have done our best to create what we think is a fair assessment.

Now, onto a few specifics:

Call me when the billions of people living in India and China are part of your Green Challenge. Until then, I'm getting in my SUV, driving three blocks to the grocery store, loading up on meat and processed food, and leaving on all the lights, the TV AND two computer monitors while I'm gone.

According to the U.N. Development Programme, India emits 1.2 metric tons of carbon per capita. China weighs in at 2.7. Call us after you’ve supplied these countries with SUVs, gas, and car keys--till then, their citizens hardly qualify to even take the Challenge!

I read the transportation file. It is positive and informative. Thank you for informing me of this article series. I look forward to the next one.

Thank you.

So, transportation to work doesn't include bike commuting or walking? And what do I check if I don't have a dishwasher?

and

Hey this massively sucks. I use bus, bicycle, or running shoes to get almost every where. What about that. I mean this is a poor excuse for a carbon calculator.

If you commute by bike or foot, you’re carbon emissions, for the purposes of this quiz, would be zero. (Though some argue the point that it does take some precious energy (in terms of fossil fuels) to make the bike and to feed the person biking or walking.) You, self-propelled TreeHuggers, would necessarily have a lower outcome, according to this quiz. Regarding the bus travel mentioned above, there was indeed an option for you. Simply enter zero for the value in the transportation methods that you never use.
Sorry, people who don’t have dishwashers. Just pick the lowest impact option. It won’t drastically affect your overall score.

I live in Oregon and I burn wood, I found the heating aspect a little biased toward the East Coast. I was hoping to take the quiz. Oh well.

We did indeed choose to leave wood-burning out of this quiz. Besides being difficult to find figures and calculations regarding national averages, we also know that not many people nationally use wood to heat their homes. And even though you are presumably using a cleaner alternative, you’re still emitting some pollution into the air. I suggest you select the below-average natural gas option for heating, which will give you a relative figure. Even if it’s higher than your actual emissions by a bit, you can still participate in the Challenge.

The quiz doesn't take into account carsharing or car rentals - I don't own a car, but I do drive... as do plenty of other city folk around here.

If you don’t own a car, but do often use a rental or car-sharing program such as Zipcar, simply estimate the number of miles you drive each year. If you typically rent the same type of car—say, a compact that gets about 30 miles per gallon—then use that average for your input. If you typically rent or share various different types of cars—an SUV one week, a mid-size the next, a hybrid the next—I suggest using the national mpg average we chose to go with in the Challenge, 24. It doesn't matter that you won't fill in the "I don't own a car" block--your entry for car-share/rental will more accurately affect your total. And again, like any carbon footprint quiz, we cannot tally exact figures for each individual; the number that comes up in the end is approximate, but accurate enough to be realistic. If the questions don’t accurately reflect your specific circumstances, get creative.

Also we have a heat pump which runs on electricity. Not everyone heats with oil or gas.

If your house is heated via electricity, then this would be reflected in your electric bill, which would in turn be reflected in the quiz. If you prefer not to look at your electric bill, then you should probably choose the above-average option for electricity use. You, electric-heated home owners and renters, could then enter zero for oil and natural gas (unless your dwelling uses one or both for another purpose.)

The quiz is misleading. It does not account for a lot.

What is food within your region? For NY does that mean a CSA or from as far away as Maine? The 100 mile diet? What, it should really specify...

It assumes an average American house. My house (well parents) is old but very efficient old heating (from WW2 or sooner). The Power Authority rated our house as being somewhere about 90% efficiency or something. We have double paned glass. We barely put our heat on and no matter what it never goes on before Nov 1st.

It assumes that everyone has a dishwasher. We have NONE in my house, but instead fill a sink with some water and soap to wash our dishes... novel eh.

It probably assumes the average household does not clean their lint trap in the clothes dryer, which reduces efficiency. In my house (partly because my mom grew up in a house of firemen), we religiously clean it out... if we don't, it is hell or high water.

Clothing: I purchase a lot from sustainable retailers or the salvation army/good will. I can't purchase all because of the general neglect of producing CORPORATE attire, let alone corporate attire to fit a NON-Apple body type or a Tall female.... a white suit with elastic waist, no shape, and a slit halfway up the thigh doesn't really work here people.

A/C: we have one A/C that is used only is the most horrid of humid conditions. Otherwise, the good old fan is fine for my house. The quiz should account for type of A/C (window, central air) etc instead of an average... because frankly, I reckon my household (being as frugal as we are) are more than well below the national average. The house is VERY small.

Work: I work in public transit (albeit construction of it), but one would think someone who works on increasing sales for PVC pipes or outsources abroad (more milage to bring the product to your door) is a bit different than someone who is upgrading and making a public transit system for NYC more efficient -- the end product for mine will let people fill in their Subway/Train milage instead of cars... We spend almost a 1/3 of our time and work -- this needs to count somewhere.

There were other issues I had with this quiz, in terms of accuracy, but this is all I can think of for now....

Not sure why my prior response didn't get posted, but I'll abridge it.

I understand that there's a lot of variation for statistics on the Internet. Contrary to your presumption, I wasn't "scouring the Internet" -- I'm actually very familiar with these numbers, and know where the proper sources are, and also the nomenclature used in the field.

Some of your numbers are on the mark, as I noted, but some are so far off the mark, it's not a matter of there being some slight variation among so-called "authorities" for these numbers. The two that are furthest from the mark are your claims that "today's passenger cars average just 24 miles per gallon, the lowest level since 1980" and that "passenger cars alone are responsible for 25 percent of the greenhouse gases we produce".

In the former case, passenger cars get 40% better fuel economy than they did in 1980. You can debate whether that's a substantial improvement, but it certainly isn't the same as 0%, per your claim.

http://www.bts.gov/publications/national_transportation_statistics/html/table_04_23.html

In the latter case, you're saying passenger cars put out 25% of US greenhouse gases, when in reality it's 9%. Your number is off by a factor of 3 (ie, 300%). Take 636.4 Tg -- the sum of emissions from automobiles using gasoline and diesel in Table 3-7 from this part of the EPA's most current greenhouse gas inventory.

http://epa.gov/climatechange/emissions/downloads06/06Energy.pdf

Then divide that by the total emissions of 7,074.4 Tg, from Table ES-2 from the executive summary of the same report:
http://epa.gov/climatechange/emissions/downloads06/06ES.pdf

That comes to 9%.

Like I said in my prior comment, part of the problem you might be having is one of nomenclature -- eg, thinking "passenger cars" means "all the cars, trucks, and SUVs we drive", when in fact it is synonymous with "automobiles" and is distinct from "light trucks". "Light vehicles" is the terms used to refer to "all the cars, SUVs, and trucks (with a gross vehicle weight rating (GVWR) of 8,500 pounds or less".

But even considering nomenclature mistakes, your numbers still miss the mark by a fairly large amount in the two cases I just mentioned.

Precision is impossible, sure. But we can strive to arrive at the best and most reliable numbers, and know when we're in the right ballpark. It's one thing to say that cars aren't more efficient than they were a quarter century ago, when in fact they're 40% more efficient (or, technically, have 40% higher fuel economy, since their efficiency gain is even greater, considering that vehicles are much heavier and more powerful than 25 years ago).

It's also very different to say something is 1/4 of a problem versus 1/10 of a problem.

The per capita emissions numbers I calculated were based on the EPA's greenhouse gas inventory divided by the estimated population of the US as of 7/1/2004, per the Census Bureau. That's a solid number. As is the percentage of energy consumed directly by individuals. In the context of some "carbon reduction" effort, people need to know there's a big difference between the per capita carbon footprint (26.5 tons) and the actual footprint directly controllable by them (at most 10.9 tons). Someone could completely de-carbonize their personal life, but they'd still have 15.6 tons of per capita emissions hanging over their heads.

Perhaps if you folks provided links to where you're getting all your stats, it would be easier to clear up any discrepancies, instead of just writing it off to some sort of "numbers are what you want them to say" or "he said/she said" sort of thing. We all want to make sure we understand things accurately to inform our actions, as you said.

Ditto to comments about not having a dishwasher and not even driving a car at all. I might add that the quiz left out a person's consumption of material goods, such as clothing, electronics, books, furniture, etc. Also, lifestyle habits such as self-efficiency with food and "real" recycling are left out of this quiz, making it less credible.

For example, people who buy only used clothing and goods, and never purchase the latest fashions or gizmos (i.e. iPods, Elmos and XBox 360s) are not given the carbon-reducing credits due to them. And what about metal (aluminum and steel) and glass recyclers? And home gardeners?

I haven't bought any new clothing in 7 years, and personally recycle 40,000 (yes, forty thousand) cans and bottles every year (from my co-workers and friends). My only material indulgences are gettng a cheap laptop computer every 6-7 years, and a new cheapo cell phone whenever mine breaks (about once every 3-4 years. And I also grow my own fruits and vegetables in my backyard garden, and give me kids mostly used toys and clothing. Plus I don't drink bottled water like Evian or Poland Springs.

I'd like to see these components added to the Carbon Quiz before I'd give it any serious consideration.

The Slate Green Challenge isn't working for me. I don't even own a car, and I use feet or public transportation to get where I want to go.

I don't have a dishwasher (unless you count my hands), I don't have a dryer (unless you count the clotheslines out back), I've already replaced nearly all of the light bulbs in my house with the compact fluorescent ones (I replace the incandescents as they burn out). The windows are already double-glazed--that was done over 10 years ago. The house is properly insulated. We've always kept the thermostat on "too damn cold" in winter. The house doesn't even HAVE a/c, and we haven't installed any of those window units either. The appliances are all energy-star. The garden has plenty of trees and windbreak fencing so that the temperatures are moderated summer and winter.

I re-use plastic containers and plastic shopping bags until they just shred or crumble. Our waste pickup company supplies us with recycle bins, and we use them. I'm too cheap to buy new clothes until they can't be patched any more--I work in a place where the dress code is "Wear clothes. PLEASE." I don't buy stuff I don't need. We compost leaves and garden and kitchen waste year-round. At least half of our meals are vegetarian (not vegan, but at least vegetarian).

So why isn't the challenge working? Because it assumes that I HAVE all this stupid stuff and USE it. It assumes that I'm a consuming zombie. Well, I'm not, I don't, and haven't for nearly all of my life.

The only things that I can realistically do to further reduce my carbon footprint are to install solar shingles when the roof needs to be re-done, and to replace the water heater with one of those on-demand models when the current one finally fails.

Aren't there anything that urban renters can do? I can't replace my windows or add caulking, can't even turn down my heat because its a radiator - there wasn't one thing on this week's challenge that I can do - come on.

I took the quiz a while ago but it is clear that this was not edited/evaluated by many people to get different points of view. There are several questions that require answer that do not apply to me. For instance, I do not have a dishwasher, nor do any of my friends (we are mostly apartment dwellers). I also do not have a car and rely totally on public transport and my bike, and felt the test was skewed towards car drivers. Asking me to estimate the number of miles I do drive a year in a bus or with rental cars is sort of difficult too, how about asking how frequently I take the bus/subway and how far I go? Overall, the test could have been much more effective at getting the point accross if I felt the results really applied to me.

Could the survey be modified to tell people where their carbon emissions are coming from? It says I am emitting the same amount of CO2 as the average American, and yet I don't even own a car. Perhaps the subway uses more energy than I think it does? Or is heating my apartment the biggest contributor? I have no idea what changes to make in my lifestyle! Thanks...