Putting a human face on energy usage

In the News Focus Story, "Greening the Meeting" (5 October 2007, P. 36), B. Lester compares the fossil fuel energy required to transport scientists to and from a conference by airplane to the energy used by "2250 Honda Civics during a year's worth of normal driving." Another way to put a human face on fossil energy usage is to think in terms of "Virtual Persons" (VPs). (Letters)