Agriculture Reference
In-Depth Information
Today, the world's population is around 6.5 billion. Demographers suggest that
global population growth will slow and eventually peak at about 9.2 billion later this
century (Alexandratos 2005). This 50% increase in the world's population will bring
with it a more than proportional increase in food needs. This is because urbanization
and income growth will lead to more diversified diets (more livestock and fish prod-
ucts and high-value crops) and higher per capita consumption of calories. The exact
way in which diets will evolve in different societies will be influenced by history,
culture, and religion. Food needs/demands are swiftly evolving even as the produc-
tion environment itself is transformed beyond recognition.
In the future, the world's population will not only be larger and slower growing;
it will also be older, more urban, and increasingly concentrated in developing coun-
tries. Some analysts see the present decade as a unique moment in the history of
humanity: For the first time, old people will outnumber young people, urban people
will outnumber rural people, and the median woman worldwide will barely have
enough children to replace herself and the father (Cohen 2005).
However, the global level of analysis masks important differences between coun-
tries. Peak populations in some low-income and food-insecure countries are pro-
jected to be multiples of present ones (Alexandratos 2005). Many issues relating to
food security, water depletion, land degradation, and environmental destruction will
increasingly be concentrated in such countries.
In the meantime, much unfinished business remains. In 2003, 850 million people
in the world were food insecure, most of them in South Asia and sub-Saharan Africa,
where the average daily per capita food supplies in 2003 were only 2400 kcal and
2200 kcal, respectively, well below the world average of 2800 kcal (Comprehensive
Assessment 2007). Fortunately, there is evidence to suggest that successful develop-
ment and dissemination of productivity-improving agricultural technologies can help
slow population growth by generating employment, raising incomes, and improving
food availability (Vosti et al. 1994). (It is recognized that sociocultural and demo-
graphic variables such as female literacy and marriage rates are equally important in
determining fertility change.)
The challenge for food production technology and resource management prac-
tices is considerable. Several goals must be met simultaneously. Food security must
be achieved for rapidly rising populations in poor countries, but this must be done
in ways that allow reallocation of scarce water to nonagricultural uses, that reverse
or slow land degradation, and that preserve a wide range of ecosystem services.
And, all of this must be done in the context of ongoing processes of climate change
that are likely to have an impact most heavily on developing countries in tropical
environments. Further information on population growth and food availability is
provided in Chapters 21 through 24.
wAteR scARcIty
Water scarcity is becoming a major threat to sustainable food production in many
areas (see also Chapter 19). This is particularly the case in areas where the following
trends are converging:
