[Editors] MIT tracks carbon footprints of U.S. lifestyles

[Elizabeth Thomson]

For Immediate Release
MONDAY, APR. 28, 2008
Contact: Elizabeth A. Thomson, MIT News Office -- Phone: 617-258-5402  
-- Email: thomson at mit.edu

GRAPHIC AVAILABLE

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MIT tracks carbon footprints of different lifestyles
-- In America, even the smallest footprints are large
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CAMBRIDGE, Mass.--Whether you live in a cardboard box or a luxurious  
mansion, whether you subsist on homegrown vegetables or wolf down  
imported steaks, whether you're a jet-setter or a sedentary retiree,  
anyone who lives in the U.S. contributes more than twice as much  
greenhouse gas to the atmosphere as those living in the rest of the  
world.

An MIT class has estimated the carbon emissions of Americans in a  
wide variety of lifestyles--from the homeless to multimillionaires,  
from Buddhist monks to soccer moms--and compared them to those of  
other nations. The somewhat disquieting bottom line is that in the  
United States, even the people with the lowest usage of energy are  
still producing, on average, more than double the global per-capita  
average. And those emissions rise steeply from that minimum as  
people's income increases: The class estimated Bill Gates' impact as  
about 10,000 times the average.

“Regardless of income, there is a certain floor below which the  
individual carbon footprint of a person in the U.S. will not drop,”  
says Timothy Gutowski, professor of mechanical engineering, who  
taught the class that calculated the rates of carbon emissions.

The results will be presented this May 19-20 at the IEEE  
International Symposium on Electronics and the Environment in San  
Francisco.

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.

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.

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 analysis was carried out by Gutowski and 21 students in his 2007  
class “Environmentally benign design and manufacturing.” They derived  
a system for making such comparisons, which they call ELSA- 
Environmental Life Style Analysis.

Unlike some other attempts to quantify people's carbon emissions,  
Gutowski and his students took great care to account for often- 
overlooked factors such as the “rebound effect.” That's when someone  
makes a particular choice-for example, buying a hybrid car instead of  
a gas-guzzler-but then uses the money saved from their reduced  
gasoline costs to do something else like taking a long trip by  
airplane. The net impact, in such a case, may actually be an overall  
increase in carbon emissions.

“When you save energy, you save money,” Gutowski explains. “The  
question is, how are you going to spend that money?”

The students looked at the factors within each person's control that  
might lead to a reduction in their carbon output. They found that  
achieving significant reductions for the most part required drastic  
changes that would likely be unacceptable to most people. As a  
result, they said, “this all suggests to us very significant limits  
to voluntary actions to reduce impacts, both at a personal level and  
at a national level.”

In a continuation of the class this semester, another group of  
students are exploring this question in more detail, looking at just  
what kinds of things people really can do to limit their  
environmental impact. The question they are addressing, Gutowski  
says, is “can average Americans tighten their belts” in a way that  
would make a significant difference. Once again, the class will be  
interviewing people living in a wide variety of ways, including an  
Amish farmer. Then, after analyzing the results and possible changes,  
they will go back to the same people and ask, “would you consider  
these alternatives?”

In general, spending money on travel or on goods that have  
substantial energy costs in their manufacture and delivery adds to a  
person's carbon footprint, while expenditures on locally based labor- 
intensive services-whether it's going to a therapist, taking an art  
class, or getting a massage-leads to a smaller footprint.

But the biggest factors in most people's lives were the well-known  
obvious energy users: housing, transportation and food. “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.

If nothing else, the members of this class got a whole new  
perspective. “The students really got into it,” Gutowski says. “It  
raised everybody's awareness about the issues.”

--END--

Written by David Chandler, MIT News Office