Part Six, Issue 18 Threats to Ecosystems

Objectives After reading the assigned chapter and reviewing the materials presented the students will be able to understand: Global trends in grain production. Can global supplies feed a growing population?

Why we Eat? The basic chemical components in the human body are carbon, hydrogen, oxygen, nitrogen, and a few other elements. These combine to form molecules of protein, lipids, carbohydrates, and nucleic acids. The molecules interact to build more complex structures: cells, tissues, organs, organ systems, and ultimately the individual. Inadequate nutrition leads to undernourishment or malnutrition. Globally around 1 million people are underfed.

What we Eat: Grains and the Origin of Agriculture We are extremely dependent on only a few grains: corn (maize), wheat, rice, and barley. Most wild biomass is wood or leaves which we cannot digest. Cultivated peas are ten times bigger than their wild ancestors. We became dependent on a few grains because: Their ancestors were edible and plentiful in the wild. They grew quickly and were easily collected and stored. They contained protein and were rich in carbohydrates.

Global Grain Production Over most of human history, farmers have increased agricultural output mainly by plowing up forests and natural grasslands. Limits of geographical expansion were reached long ago in parts of India, China, Egypt and Western Europe. Intensification of production – more output from the land – has become a growing necessity. This has been achieved in Asia through producing several crops a year in irrigated ecosystems using new fast growing crop varieties – “Green Revolution.” Whenever world carryover stock drops below 60 days of consumption, prices begin to rise (Lester Brown of Earth Policy Institute).

Grain land Area Many rural and suburban dwellers are used to seeing farms being converted into residential subdivisions. Globally grain land has dropped from 674 million hectares (1 hectare = 2.47 acres) in 1999 to around 647 million hectares in Although per capita grain land harvested has decreased in recent years, this decrease has been offset by increase in output by use of new strains of wheat and rice along with greater irrigation.

Grain and Meat Production Annual meat consumption is about 300 pounds in the United States. Some 15 billion livestock (11 billion of which are poultry) exist to satisfy the demand for meat. Much of the world’s grain harvest is fed to cattle and other livestock. In 2006 the Earth Policy Institute estimated that 714 mt (million tons) out of a total harvest of 1,984 mt were fed to animals. It is estimated that a switch to grass fed livestock in the United States would allow about 130 million tons of grain to be diverted for human consumption which could feed about 400 million people annually.

Summary Inadequate nutrition leads to undernourishment or malnutrition. Globally around 1 million people are underfed. We became dependent on a few grains because: Their ancestors were edible and plentiful in the wild. They grew quickly and were easily collected and stored. They contained protein and were rich in carbohydrates. Over most of human history, farmers have increased agricultural output mainly by plowing up forests and natural grasslands. Whenever world carryover stock drops below 60 days of consumption, prices begin to rise (Lester Brown of Earth Policy Institute). Although per capita grain land harvested has decreased in recent years, this decrease has been offset by increase in output by use of new strains of wheat and rice along with greater irrigation. It is estimated that a switch to grass fed livestock in the United States would allow about 130 million tons of grain to be diverted for human consumption which could feed about 400 million people annually.

Home Work 1. Why did we become dependent on a few grains? 2. When do prices of grains begin to rise?