I always felt a little uncomfortable about the idea of calculating my own ecological footprint…now I know why:
 
In an experiment with 212 undergraduates, Psychologists Amara Brook and Jennifer Crocker found that for those “not heavily invested in the environment”, negative feedback about their ecological footprint undermined their environmental behaviour.
[ArticleinSocial Influence 6(2):113-128 · April 2011]
“Rather than changing their ways to protect the environment, the results of this study suggest that these [people] may give up on their efforts to protect the environment”, they wrote.
 
However for those “more invested on the environment”, calculating their ecological footprint promoted more sustainable behaviour.
 
This research was reported in USA Today, but doesn’t seem to have been formally published yet because I can’t find it on Google Scholar.
 
However if you’re keen you could email Amara directly on atbrook@scu.edu and maybe she’d send you a copy.
 
It’s easy to guess at the mechanism at work: a straightforward (and, when you think about it, fairly predictable) case of DENIAL (aka Cognitive Dissonance).
 
Incidentally, while I was tracking down info on Amara Brook I stumbled across a “Conservation Psychology” website with an amazingly detailed collection of resources, including a huge number of scholarly articles on the subject: http://www.conservationpsychology.org/resources/articles/
 
The USA Today article also reported some interesting research, by Elizabeth Nisbett and John Zelenski at the Carleton University in Ottawa, that found that people tend to systematically underestimate how much happier they’ll feel from spending 15 minutes outside, and overestimate how happy they are being inside.