Ecology Footprint Quiz
by J. Zimmerman.

For three years my Ecology footprint was about 80% of the average for the USA; but that is still more than 3 times the world average, and denies me the right to say:

Ego eximo minime carbo carbonis
['I have a small carbon footprint']
as rendered into Latin by Don Maier].

Here are the summary data - click on the year to get details. Better yet, try it yourself: check the Earth Day footprint program just like some friends tried it.

Year My footprint
USA average footprint
(Acres per person)
Mine as % of USA average My footprint
World average
(Hectares per person)
Mine as % of world average
Earth Day program
20 acres 24 acres 83%
but only 40%
with the ZSEF
8.1 hectares 2.8 hectares 289%
but maybe under 140%
with the ZSEF
Redefining Progress program
26 acres 31 acres 84% 10 hectares ?2.6 hectares
(estimated by averaging
2001 and 2003)
LEAD program
18.5 acres 25 acres 74% 7.5 hectares 2.4 hectares 312%

Note: (1) Each year the quiz was at a different web location and the questions were slightly different. So the formula would have been different too, introducing a little erraticism into the absolute values. I believe the percentages are more reliable than the absolute data. And that the results shown below where many people took the 2003 quiz are comparable.
(2) 1 hectare = 2.47 acres.

Dang. My percentage appears to be increasing. As these programs are from different web sites each year, some variation may be differences in what data are collected and what formulae manipulate them. However, I would expect an increase from 2001 to 2003, as I began to eat meat (about 3 oz per day).

The worldwide average footprint of 2.4 hectares (6 acres) per person exceeds the available acreage. I don't know what that means but it sounds dangerous. It sounds like the world is overpopulated

Results using Earth Day footprint program:

Type of footprint My Acres USA average (Acres per person)
Food 4.7 acres
Transportation (mobility) 0.5 acres
Housing (shelter) 8.9 acres
Other footprint (goods and service) 6.4 acres
Total 20 acres 24 acres

This puts me at 83% of average. But I'm only 40% when I include the Zimmerman Shadow Ecology Footprint!

The Earth Day site said:
Worldwide, there exist 4.5 biologically productive acres per person.
If everyone lived like you, we would need 5.8 planets.

Results using footprint program (at that time it was at Redefining Progress):

Type of footprint My Acres My Hectares USA average (Acres per person)
Food 4 acres 2 hectares
Transportation (mobility) 5 acres 2 hectares
Housing (shelter) 10 acres 4 hectares
Other footprint (goods and service) 7 acres 2 hectares
Total 26 acres 10 hectares 31 acres

The Redefining Progress site said:
Your footprint is 84% of the USA average.
Worldwide, there exist 5 biologically productive acres per person.
If everyone lived like you, we would need 5 planets.

The Redefining Progress led to the Ecology Footprint Quiz through the British Leadership for Environment and Development (LEAD). These are my results:
Type of footprint My Acres My Hectares USA average
(Hectares per person)
World average
(Hectares per person)
Food 3.3 acres 1.3 hectares 2.9 hectares
Transportation 2.6 acres 1.0 hectares 2.1 hectares
Housing 7.6 acres 3.1 hectares 2.5 hectares
Other footprint 5.0 acres 2.0 hectares 2.7 hectares
Total 18.5 acres 7.5 hectares 10.2 hectares 2.4 hectares

That put me at 74%.

They asked you how much of the biosphere should be set aside for other species. I said 80%.

Based on my above results, their model said:
Your choice means that you maintain that each person should be able to live a satisfying life within an average of 0.4 hectares or 1 acre.
The model said that my 80% and footprint data meant that it required 18.7 Earths to support each member of the present human population at my standard of living.

My response is:

It is obvious that the impact of people on the planet increases with population. But it was in 1998 that Yale economists William D. Nordhaus and Joseph Boyer first developed a model of the cost of the human population on future living standards. They found that:
The lifetime cost of each person's impact on their environment was then about $100,000 in a high-income country. It fell with income, reaching $2500 per person in low-income countries.

The Zimmerman Shadow Ecology Footprint

Some friends wanted an "extra deduction for not having kids". Therefore, as the data start to come in from my friends, I have came up with the Zimmerman Shadow Ecology Footprint.

This Shadow Footprint is the shadow of additional load that is cast by people with children (because they are throwing a shadow of increased population into the future) and by people with larger pets.

While there are many ways to create a different formula, this is the one that I am using:

In the above:

What is the "shadowed footprint" (the sum of the basic ecology footprint plus the ZSEF) for the average USA citizen? It comes to a value of "50-acres" for this footprint-with-shadow. Here's how.

USA citizens have a fertility of over-replacement, contributing to world population increase. So the average adult American shadow print is over 24 acres - say 26 acres - for the "kid component".

Then, given than some people have horses, many have dogs, pot-bellied pigs, etc., the average shadow print (I am guessing wildly) is say 2 for pets.

So the total is 52 ( = 24 + 26 + 2)

These are not actual acres; they are just for comparison purposes. And for easy comparison purposes, and given that all of this is very approximate (as in "smoke and mirrors"?), I am just going to call that "50", as any economist or statistician might do.

Results in 2003 by others, living in USA except as noted; some data added for 2008 (using calculator referenced in footnote [1]):
id Footprint
Zimmerman Shadow
Ecology Footprint

(ZSEF) (Virtual acres)
Footprint with shadow
(Real and virtual acres)
Shadowed footprint
as % of average USA
"50-acre" footprint-with-shadow
Scott (1 kid) 6 acres 3 9 18%
hc (1 dog) 15 acres 1 16 32%
mc (1 cat;
1 very small dog)
17 acres 1 18 36%
(In 2008 "I contribute annually 800 KwH to grid")
20 acres [1] [2] 0 20 40%
J. 20 acres. In 2008: 20.2 acres [1]. 0 20 40%
se (1 kid;
self-generates all electricity
and contributes to grid)
14 acres [2]. 7 21 42%
co (1 small dog) 22 acres 1 23 46%
ha (2 kids) 12 acres 12 24 48%
ca 24 acres 0 24 48%
Ariadne (Scotland)
(3 kids, 1 bunny)
10 acres 15 25 50%
ho 32 acres 0 32 64%
ma (1 kid) 23 acres 11.5 34.5 69%
hb (2 kids,
1 big infertile dog)
19 acres 20 39 78%
ba (3 kids) 16 acres 24 40 80%
si (4 kids,
1 dog, 2 cats)
19 acres 39 58 116%
Arnold S. (4 kids)
Al Gore
44 acres 88 132 264%

[1] 2008 data are through footprint calculator at .

[2] No acreage reduction is made for contribution to the grid; it would be helpful if the footprint programs allowed for that.

Here is clarification of some terms used in the tables above.

'Food' includes meat consumption, calorie consumption, food wastage, and locality of purchased food.

'Transportation' includes miles driven, ride sharing, fuel efficiency, use of public transportation, and air travel. The average car in the USA is driven (sit down, wait for it, ...) 17,000 (seventeen thousand) miles annually.

'Housing' includes size of the home (or for Republicans, homes) you live in, use of green electricity, and use of energy efficient appliances.

'Other' footprint depends on the quiz. It may include goods and services.

Range in 2003: "in some countries, the average is as low as 0.5 hectares (1.2 acres), while others use as much as 13 hectares (32 acres) per person. Even within any given country, individuals' footprints vary widely."

Try it! Remember that the source of the models and the comparative USA footprint varies year-to-year.

Fine print: Your mileage may vary; there is some rounding in the data.

A comment on 'environmentalists' like Al Gore

Comments by Saul Griffith, an eco-minded engineer, cited by David Owen in his The New Yorker (May 17, 2010) article "The Inventor's Dilemma: an eco-minded engineer discovers the limits of invention" [p. 30]:

Griffith told me,
"I know very few environmentalists whose heads aren't firmly up their ass. They are bold-facedly hypocritical, and I don't think the environmental movement as we know it is tenable or will survive. Al Gore has done a huge amount to help this cause, but he is the No. 1 environmental hypocrite. His house alone uses more energy than an average person uses in all aspects of life, and he flies prodigiously. I don't think we can buy the argument anymore that you get special dispensation just because what you're doing is worthwhile."

Griffith includes himself in this condemnation. He said,
"Right now, the main thing I'm working on is trying to invent my way out of my own hypocrisy."

And of course as Griffith already has at least one child, no matter what he does, he is developing his Zimmerman Shadow Ecology Footprint.

See also

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