EnvironDesign Notebook: How Many Planets do You Require?

June 23, 2009

Ecological footprints—an eye-opening, attention-grabbing measuring stick of our lifestyle impacts on the planet—tell us how many planets we need to survive.

After a recent CEU presentation on sustainability, a woman approached me with an interesting personal issue. Her teenage son was “in her face” regularly about the fact that her generation was ruining the planet for his. She was carrying guilt for her whole generation, so I asked her about his impacts on the planet—e.g., did he turn off lights and electronics when not in use? Did he shun the latest new electronics and clothes? Did he ride his bike to school or to his extracurricular activities? And what about his eating habits—did he prefer minimally-packaged, locally-grown organic food?

I guessed the answers by her expression and suggested that, together, they use an ecological footprint calculator. A what?? According to Wackernagel and Rees¹, an “ecological footprint analysis is an accounting tool that enables us to estimate the resource consumption and waste assimilation requirements of a defined human population or economy in terms of a corresponding productive land area.” Stated a bit simpler, the kids footprint site² says it estimates how much productive land and water you need to support what you use and what you throw away.

My own definition is that an ecological footprint is an eye-opening, attention-grabbing measuring stick of our lifestyle impacts on the planet, so I warned the concerned mom that the ecological footprint calculator would provide a surprising experience. It sure did for me.

For nearly 40 years, the U.S. Environmental Protection Agency has required measurements of pollutants being emitted into the air, water and land. Various governmental and non-governmental organizations have done the same around the world. The UN Environmental Programme and other global research organizations have attempted to compile the information to understand the collective damage we are doing to the planet. These are vital functions, but they don’t measure sustainability.


  1. Wackernagel, M. and Rees, W. Our Ecological Footprint: Reducing Human Impact on the Earth, New Society Press, 1996 And www.footprintnetwork.org
  2. www.kidsfootprint.org

The design community sometimes asks about the carbon footprint of the materials, manufacturing, and/or shipping of our products. Their question focuses primarily on the greenhouse gas emissions that impact global climate change. That too is of vital importance, but it doesn’t tell us the sustainability story, either.

Various organizations can tell us how much oil is in the ground, how much freshwater remains uncontaminated, the number of hectares of forest or productive cropland remain, the populations of the world’s fisheries, or how many adult highland gorillas are surviving—all vital pieces of the puzzle.

What about the totality of the planet’s resources in relation to those of us who depend on them? How can we measure sustainability’s three Es?


Several organizations are looking at the bigger picture and how to incorporate the work of all those groups into a set of sustainability indicators (i.e., measuring sticks for our impacts on the planet that unite environment, economy and equity). Agenda 21 provides a global blueprint for addressing those issues, and the ecological footprint is a measuring device that tells scientists and politicians how we’re doing. Ecological footprints are also an excellent tool for relaying that knowledge to citizens of the planet about their impacts on the sustainability of our lifestyles.

Ecological footprints tell us how many planets we need to survive.

The ecological footprint calculators tell us how many planets it would take for all of us to have what we need if everyone lived a lifestyle like our own. The science behind it analyzes all those things I previously discussed, and more. The multiple choice calculators make it easier for us to do some basic personal analysis without having to understand all the formulas that support them. Some of the quizzes are so basic that they are difficult to answer due to the groupings of answers. I tested several so that I could recommend a couple for you to try. I also wanted to re-measure my own personal footprint since I hadn’t done so for a while, and, I confess, to be able to gloat just a little (more on that later).

The calculators are actually measuring the number of hectares (one hectare equals 100 acres) of productive land needed to supply our needs and absorb our wastes. The term is “carrying capacity,” but the translation into “planets needed” helps to get the attention of citizens who are unaccustomed to thinking in hectares. Since the mid 1980s, we, as a planet, have been in a condition called “overshoot” because we are using resources faster than they are being regenerated. How much?

We (collectively) need 1.3 planets (1.5 by another calculation) to provide for our current worldwide usage of resources. In other words, it takes the Earth one year and four months to regenerate what we all use in one year¹.

But there is more to think about than the average of 1.3 planets, because we aren’t all using resources equally. Many Americans may need several more planets.

I recommend two Web site calculators because their organizations also provide excellent supporting information. One is from the Global Footprint Network (with its very impressive Advisory Council), and the other is from Redefining Progress and is used by the Earth Day Network. I tried both calculators and was floored by the results.


Keri Luly has elected to donate her monetary compensation for the articles she writes to an environmentally proactive organization of her choosing. This issue, she has selected the Global Footprint Network, which was established in 2003 to enable a sustainable future where all people have the opportunity to live satisfying lives within the means of one planet. Its programs are designed to influence decision-makers at all levels of society and to create a critical mass of powerful institutions using the Footprint to put an end to ecological overshoot and get our economies back into balance. Visit www.footprintnetwork.org to learn more.

First, a bit of background: I often get kidded about my lifestyle. I recycle everything I possibly can. I drive a nine-year-old Honda Civic. I eat a lot of vegetarian meals and no red meat, ever. Visitors to my Midwest abode had better wear sweaters in the winter. I’m not much of a shopper and prefer to go to architectural salvage yards than to high-end stores. My brother once gave me unlimited grief when I picked up the extra unused paper napkins after a meal in a Mexican restaurant—I knew the person who cleared the table would immediately throw them away and I could at least put them to use first! So I assumed I would score fairly low, planet-wise.

Global Footprint Network (www.footprintnetwork.org) offers two calculator versions: a basic one that is quicker and makes more assumptions based on general questions; and a more in-depth version that gets a bit more specific. You start by creating an avatar, and, as you enter answers about your lifestyle, a scene is built around that avatar, fitting your responses. Some words of warning: Don’t try to use the back key to change an answer once you’ve started the calculator or you’ll lose everything … and be ready to answer questions about your electricity and natural gas bills.

Redefining Progress’ calculator is in greater depth with more questions. It provides a running calculation window that compares your answers with the average calculations of people in your country as you enter your information. It also has interesting blurbs that can be clicked to briefly explain the importance of the information being evaluated. Be prepared to provide estimates of the number of miles you use an automobile, bus, train, and airplane over the course of a year.

Each calculator reviews similar aspects of your lifestyle, typically including varying levels of detail regarding your housing, food choices, transportation choices, energy and water use, purchasing habits, and waste handling. A number of societal assumptions about community infrastructure are made based on where you live, but the calculators are specific to your lifestyle.

There is a wealth of valuable information you will learn on both Web sites, but I can only provide a few tidbits here. Overall, high income countries have a much larger ecological footprint than middle and low income countries, and both sites provide ideas for reducing our footprints. You know what? They aren’t painful and they often benefit our personal lives by saving money and making us healthier. Not a bad thing—and now that I know my lifestyle requires almost five planets (ouch—it’s all that flying and eating out!), I’m ready to make some adjustments. Try it yourself!

Keri Luly, LEED AP, is Allsteel’s stewardship coordinator and regular contributor to EnvironDesign Notebook. She can be reached at [email protected].

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