Environmental Engineering Reference
In-Depth Information
Europe and North America, with most food lost during the consumption stage: more
than 10% for meat, about 25% for cereals, and 20%-30% for vegetables; absolute
losses are much smaller in low-income countries, where they are dominated by waste
in the postharvest processing and distribution stages, that can reduce foodstuffs
reaching households by as much as 20% for cereals and 30% for tubers and seafood
(Gustavsson et al. 2011). What this means in food energy terms can be appreciated
by comparing supply (from food balance sheets) with actual intakes: in the EU and
North America, the per capita rates for supply are in excess of 3,000 kcal/day, the
rates for actual intake are 30%-40% lower.
A more accurate approach to quantifying this waste was used by Hall et al.
(2009), who modeled metabolic and activity requirements in order to i nd the most
likely food intake of the U.S. population between 1974 and 2003. That rate ranged
from about 2,100 to 2,300 kcal/day, but during the same period the average food
supply rose from about 3,000 to 3,700 kcal/day, and the country's food waste thus
increased from 28% of the total retail supply in 1974 to about 40% three decades
later. Similarly, a detailed survey in the UK found that British households waste
about 31% of purchased food (WRAP 2009). And even Japan, the least wasteful
of all afl uent countries, now loses about 25% of its total daily food supply (Smil
and Kobayashi 2011), and rising food losses are reported from China. The irratio-
nality of wasting 20%-40% of all produced food is self-evident, particularly given
the rising incidence of obesity.
Conditions needed to minimize human claims on the biosphere's productivity are
not difi cult to summarize:
•
The global population should be stabilized at less than nine billion people.
•
Food should be produced using the best agronomic practices, including optimized
irrigation, fertilization, and the use of pesticides, reduced tillage, and crop rota-
tions rather than monoculture.
•
The average per capita food requirements should be limited to levels necessary to
support healthy lives of decent longevity rather than to support excessive car-
nivory and obesity-inducing diets.
•
Much more attention should be paid to postharvest food losses and to household
food waste.
•
We should pursue such difi cult but highly rewarding challenges as developing
cereal permacultures and staple grain crops able to i x nitrogen.
•
Wood output should be limited by the long-term productive capacities of forest
ecosystems and properly managed plantations.
