Effects of Global Household Proliferation on Ecosystem Services - Landscape Ecology for Sustainable Environment and Culture - page 109

numerous reports at the local level. Here are three examples from Africa, Asia, and
South America. In Accra (Ghana, Africa), 2,600 ha of agricultural land per year
were converted into residential areas (Maxwell 2000 ). From 1995 to 2005, Ho Chi
Minh City of Vietnam lost more than 10,000-ha agricultural land to housing,
roads, and other built-up areas (Van 2008 ). Similar patterns are common in China
and Indonesia (Verburg et al. 1999 ; Weng 2002 ). In the Pampas ecoregion of
Argentina, 39,187 ha of farm land have been converted to exurban use (Matteucci
and Morello 2009 ). An immediate impact of housing expansion is the loss of peri-
urban agriculture, which is usually significant in providing perishable food to the
urban areas (Matuschke 2009 ). As a result, agricultural production may be forced
to shift to less productive areas and result in yield losses and increased cost of
transport.
Food production is further compromised by the use of water by more house-
holds because more households require more water for daily consumption and
reduce the retention of water because of the impervious surfaces. After the surface
water and groundwater in the residential areas cannot meet household demand for
water, households have drawn water from far places. This creates cascading effects
on distant ecosystem services (Liu et al. in press ) and reduces the capacity of food
production in distant places (by lowering water table and increasing dry zones in
soils), in addition to the agricultural areas that have been converted for residential
use. All these affect food security and water security, and ultimately security of all
ecosystem services.
Historical trends in household size suggest that there will be many more
households even if human population declines. If average household size world-
wide were the same as that of the United States (2.5 people per household) in
2010, then the world would have over 40 % more households, or 800 million
additional households in the 172 countries with available data (2.7 billion
households rather than 1.9 billion households). If each household occupied a
210 m 2 house (the average U.S. house size in 2002), then 168,000 km 2 extra
housing area would be required. Even assuming each house has two-stories, then
housing needs 89,000 km 2 of additional land area. That would be twice the size of
California. Even if the average house globally is half of an average U.S. house,
44,500 km 2 would be needed to accommodate additional households. These
estimates have not taken land area for other purposes associated with housing (e.g.,
infrastructure such as roads, services, yards) into account. Including land for
associated functions would require 2-4 times as much land for each home. So the
total area for housing would take up nearly half the size of the continental United
States (Peterson et al. in press ) and severely limit food production.
6.3.3 Payments for Ecosystem Services
Household proliferation has important effects on payments for ecosystem services
because many payments for ecosystem services programs are implemented at the