The first in this series by Heidi Sopinka notes that the fastest growing type of household in Canada is the single person. " The new solo-living cohort are young (25 to 44), far more flush than the thrifty jar-reusing widows that once ruled the one-person roost and, as it turns out, the biggest consumers of energy, land and household goods. Now that their numbers are shooting up, people who live alone represent what Joanna Williams, a sustainable development professor at University College London, calls "an environmental time bomb." From washers to toasters, singletons burn through just over twice as much energy per capita as those who live in a four-person household."
Given that most single people live in smaller places downtown, and often do not have cars, I am not certain that Professor Williams' statement would hold up in North America but it is provocative.
Sopinka suggests co-housing, community kitchens (like the Vancouver one shown in picture) as "a way for people to get together to cook in large quantities and then parcel it out." and getting a room-mate. ::Globe and Mail