Failing Sustainability 101

Ever since my youth I've been a numbers type of guy. As a teenager in the 1950s I discovered that the typical American woman was having 3 or 4 children and I calculated that the USA was in for a big population explosion. At about the same time, Chinese women were having even more children than Americans. The fact that these two countries together are currently responsible for half of the entire anthropogenic contribution to increasing atmospheric carbon is partially a result of the large population increases engendered by these high fertilities.

Unfortunately, fertility is a forgotten player in today's "environmental sustainability" agenda being advocated in so many countries, including our own. If your environmental guru is a global warming guide from Al Gore, Sierra Club, NRDC, Union of Concerned Scientists, Environmental Defense, Outside Magazine's Green Issue, Time Magazine's Global Warming Survival Guide, or indeed the entire mainstream U.S. environmental movement, then you will find that the number of children a couple has is not a component of anybody's sustainability equations.

This omission introduces dramatic errors into a major new international poll, "Greendex 2008," commissioned by the venerable scientific and educational organization, the National Geographic Society. A total of 14,000 people in 14 countries were queried on a wide range of topics to determine their environmental footprint and "to promote environmentally sustainable consumption". The survey was constructed with the help of 27 experts based in many of the countries included in the study. This survey is especially significant because National Geographic intends to repeat it year after year to determine how the world and how each country are faring. Thus, it is important that the survey be as error-free as possible.

Should you be interested in quickly finding out how sustainable your personal behavior is according to National Geographic you can go to and then click on "GO NOW" in the upper right corner of the webpage.

After I answered the 12 multipart questions, the website calculated my "Greendex" score. The higher the score, the smaller is one's environmental impact. The last of the 12 questions asked about the number of people in my household who are adults (18 and older) and children (younger than 18). My wife and I have no children, so I put "two" for the number of adults and "zero" for the number of children.

Out of curiosity, I then increased the number of children first to "one", then to "two" and so on all the way up to "six", but leaving my answers to all other poll questions exactly the same. I fully expected my "Greendex" score to go down because, all other things being equal, surely a couple who has, say, 4 non-adopted children, has a much larger environmental impact than a couple who has none. If one makes the simple assumption that, on average, a child’s lifetime consumption and, thus, environmental impact are roughly the same as that of one of its parents, then a couple (initially two people) who gives birth to 4 children (resulting in six people) has 3 times greater lifetime environmental impact than a childless couple.

Thus, please imagine my surprise, when my Greendex score went up (i.e., improved) substantially as the number of children living with my wife and me increased. Remarkably, the National Geographic survey rewards people for having lots of children! When applied to the 14 countries surveyed, a country like India is rewarded for its high fertility of about 2.8 children per woman, while a country like Japan is penalized for its low fertility of about 1.2 children per woman. Taking this topsy-turvy survey formula to its logical (absurd) conclusion, the best environmentalist would be one who produced dozens of children over his/her lifetime.

How could such a carefully constructed survey get something so important, so wrong (so backwards)? Ultimately, the fault must be attributed to the mainstream U.S. environmental movement that, for decades, has abrogated its responsibility to address in a politically meaningful way the environmental harm caused by population growth both here and elsewhere. As mentioned in the second paragraph above, one could never tell from anyone's list of "50 simple things you can do to save the Earth", that arguably the environmentally most important life decision a couple can make is to limit their number of non-adopted children to two, at most.

Ben Zuckerman is a Professor in the Physics & Astronomy Department at UCLA and a member of the UCLA Institute of the Environment. He is a former member of the national Board of Directors of the Sierra Club and is currently a member of the Board of Directors of Sea Shepherd Conservation Society and of Californians for Population Stabilization and can be reached at