Cohen's article explores the concept of "sufficiency limits" for the average contemporary home—or, a rough baseline metric of "enough" living space to meet one's individual needs while considering various environmental and social factors, such as global resource availability and equitable material usage.

In the paper, Cohen reports that standardized building codes used in the United States and many other countries define minimally "sufficient" home size as 150 square feet for a single individual and 450 square feet for a four-person household.1

However, from the standpoint of resource utilization and global equity, the maximally sufficient threshold is more significant.

Based on assessments of global resource availability and so-called total material consumption calculations developed by industrial ecologists and others, Cohen estimates that sustainability and equity considerations require that a home for a single person should be no larger than 215 square feet, and for a four-person family the maximum size should be approximately 860 square feet.

As a striking point of comparison, average home size in the U.S. today is 1,901 square feet—more than twice what could be considered sustainable.

• 1. In the U.S., average floor space per person would need to be reduced from 754 square feet to 215 square feet, which perhaps surprisingly, is roughly comparable to the amount of space available during the baby boom of the 1950s. While Cohen acknowledges the myriad political, commercial and cultural challenges of imparting such a sufficiency ceiling on current housing practices, he highlights five examples that he asserts point to shifting sensibilities: the tiny-house movement in the United States; the niche market for substantially smaller houses and apartments in the Nordic countries; the construction of accessory dwelling units in west coast cities of North America; the growing popularity of micro-apartments in New York City and San Francisco; and the emergence of co-living/co-working facilities in Europe.

  "Downsizing at such a radical scale may seem unrealistic today, but lifestyles are continually in flux and when looking back on our recent practices of spending such vast sums of money on overly large houses and creating vast separations between neighbors, thirty years from now we will in all likelihood be utterly dumbfounded," said Cohen. "The idea of spending endless hours mindlessly driving around in cars to reach houses with rooms that we rarely use, we can only hope, will become a faint memory."