According to the study, housing units throughout the world are being built at a rate that outpaces population growth, resulting in a loss of habitat, natural resources and biodiversity.

''We had hoped to find that, where human population growth was slowing, biodiversity might be given some breathing room,'' said Stanford University ecologist Gretchen C. Daily, co-author of the study. ''But instead, we've found that urban and suburban sprawl are accelerating faster than population growth is decelerating.''

A research scientist with Stanford's Center for Conservation Biology, Daily also is an associate professor (research) in biological sciences and a senior fellow with the university's Institute for International Studies.

''To our knowledge, this is the first study to look at the environmental impact of households on a global scale,'' Daily added.

Writing in the Jan. 12 edition of Nature online, she and her colleagues noted that the housing boom is largely being driven by a global trend toward smaller households. Throughout the world, the average number of people living together in a household is shrinking - primarily because of lower fertility rates, higher divorce rates, higher per capita income, aging populations and a decline in multi-generational family units, the authors noted.

''Reduction in average household size takes a double toll on resource use and biodiversity,'' they wrote. ''First, more households means more housing units, thus generally increasing the amount of land and materials (for example, wood, concrete and steel) needed for housing construction.''

Second, fewer people per household leads to higher per-capita consumption of water, fuel, land
'"/>

Contact: Mark Shwartz
mshwartz@stanford.edu
650-723-9296
Stanford University
12-Jan-2003