■ There would be less of an impact on human health problems (e.g., heart
disease).
■ There would be a reduction of the impact of global warming. For
example, 28 calories of energy are required to produce 1 dietary calorie of
meat protein compared to only 3.3 calories of energy to produce 1 dietary
calorie from grain. In addition, there would be less methane generated—
methane is 23 times more destructive as a greenhouse gas than carbon
dioxide gas (e.g., a single cow releases up to 265 pounds [120 kg] of
methane per year).CASE STUDY
TRENDS IN MEAT CONSUMPTION: The United States exports 70% of
the feed grains in world trade, supplying a foreign demand that pushes up the
prices of feed grains and, therefore, of meat in the United States. As a result
and along with greater awareness of health issues, Americans now eat about
17% less beef per capita than in 1976. However, world annual meat
production is projected to increase from 218 million tons in 2000 to 376
million tons by 2030.Malnutrition-Undernutrition
Inadequate dietary intake and disease/infections, which alter dietary
requirements and the body’s ability to absorb and utilize nutrients effectively, are
immediate causes of malnutrition. Undernutrition exists when caloric intake is
below the minimum dietary energy requirement. About 11 million children die
each year from starvation, with 850 million people (13% of the world
population) considered malnourished. Chronic undernourishment and vitamin or
mineral deficiencies result in stunted growth, weakness, and increased
susceptibility to illness.
Most of the undernourished are in developing countries. Marasmus and
kwashiorkor are protein deficiency diseases in which victims may become so
emaciated that they may be less than 80% of their normal weight for their height.
TYPES OF AGRICULTURE
Cultivated land, which has generally been forest or tall grassland before its
cultivation, covers about 9% of Earth’s land surface and produces 14% of the
land’s biomass. This section describes various types of agriculture.