Our big carbon footprints

A class of MIT students in mechanical engineering has studied the carbon footprints of different lifestyles, from the homeless to multimillionaires. And the results are both fascinating and frightening. According to the study, even the people with the lowest incomes in the U.S. emit twice more carbon than the average people on Earth. These results might be controversial because the study assumed that everyone in the U.S. is equally using government services. Here is one of the students' conclusion: 'Due to the combined effects of subsidies and rebound, the magnitude of possible reductions in energy use for people in the United States by voluntary changes in spending patterns appears limited.' But read more...

A class of MIT students in mechanical engineering has studied the carbon footprints of different lifestyles, from the homeless to multimillionaires. And the results are both fascinating and frightening. According to the study, even the people with the lowest incomes in the U.S. emit twice more carbon than the average people on Earth. These results might be controversial because the study assumed that everyone in the U.S. is equally using government services. Here is one of the students' conclusion: 'Due to the combined effects of subsidies and rebound, the magnitude of possible reductions in energy use for people in the United States by voluntary changes in spending patterns appears limited.' But read more...

Men carbon footprints

You can see on the left a representation of different estimated annual carbon footprints (Credit: Patrick Gillooly, for MIT) Here is a link to a larger version. If you cannot read what is written on the different 'feet,' here is a short explanation. "The big blue foot represents the impact of many Americans (20 metric tons); the red foot represents the carbon impact of a U.S. homeless person (8.5 metric tons); and the green footprint represents the world average (4 metric tons)."

This research has been led by Timothy Gutowski, Professor of Mechanical Engineering at the MIT, who manages the Environmentally Benign Manufacturing (EBM) research group which is focused on the environmental effects associated with manufacturing and products. For this analysis, he was helped by 21 students.

So why the rich and poor in the U.S are emitting such amounts of carbon? "While it may seem surprising that even people whose lifestyles don't appear extravagant--the homeless, monks, children--are responsible for significant greenhouse gas emissions, one major factor is the array of government services that are available to everyone in the United States. These basic services-including police, roads, libraries, the court system and the military-were allocated equally to everyone in the country in this study. Other services that are more specific, such as education or Medicare, were allocated only to those who actually make use of them."

Here are more details about this study. "The students conducted detailed interviews or made detailed estimates of the energy usage of 18 lifestyles, spanning the gamut from a vegetarian college student and a 5-year-old up to the ultra-rich-Oprah Winfrey and Bill Gates. The energy impact for the rich was estimated from published sources, while all the others were based on direct interviews. The average annual carbon dioxide emissions per person, they found, was 20 metric tons, compared to a world average of four tons."

And here are some 'funny' numbers given by the MIT class. "But the 'floor' below which nobody in the U.S. can reach, no matter what their energy choices, turned out to be 8.5 tons, the class found. That was the usage calculated for a homeless person who ate in soup kitchens and slept in homeless shelters. The person with the lowest energy usage was a Buddhist monk who spent six months of every year living in the forest and had total annual spending of $12,500. His carbon footprint was 10.5 tons."

The results of this study will be presented in May 2008 at the IEEE International Symposium on Electronics and the Environment in San Francisco (ISEE 2008). Here is a link to the technical paper that should be shown during this conference, Environmental Life Style Analysis (ELSA) (PDF format, 5 pages, 48 KB).

Here is the abstract of this paper. "In this study we connect life styles and spending patterns to environmental impacts and economic implications for people living in the United States. The results show that even the most modest life styles (Buddhist monk, homeless etc) have impacts much larger that the world average.

And here is an excerpt from the results. "This study brings attention to two aspects of life style impacts in the United States. First, by including the subsidies, we identify a floor, below which environmental impacts for people living in the United States do not drop. [...] Furthermore, such a level, we believe, is not obtainable for the average American on a voluntary basis. Which brings us to our second point; due to the combined effects of subsidies and rebound, the magnitude of possible reductions in energy use for people in the United States by voluntary changes in spending patterns appears limited."

Not very encouraging, isn't? Here is the only possible solution to reduce U.S. carbon emissions according to Gutowski. "'The simple way you get people's carbon use down is to tax it,' Gutowski says. 'That's a hard pill to swallow -- politicians don't like to step up' to support such measures. Absent such national actions, he says, it is important to study 'what role consumer choices can play' in lowering the nation's carbon emissions."

[Final note: Heather Clancy, a ZDNet blogger fellow, wrote a post about the same subject. Please read this post, "Turns out it's harder to be green when you have a lot of green" (ZDNet's GreenTech Pastures blog, April 28, 2008). And please notice that I've borrowed part of the caption of the illustration above from this post.]

Sources: David Chandler, MIT News Office, April 16, 2008; and various websites

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