- Population
Consumption index by country, MSNBC Popup

At the moment the United States uses about one-third of all the raw materials consumed each year. Think of it: less than 1/15th of the population of the world requires about five times its "fair share" to maintain its inflated position.... Only 25% of us live in rich, industrialized countries like the United States.

The rest of the world lives in less prosperous countries which together account for just 15% of the global economic activity. These countries tend to have high population growth.

Many nations, especially those in arid areas such as the Mideast, suffer from serious problems providing adequate water supplies. Nations such as Egypt and Israel consume almost all available water, and Libya actually consumes almost 4 times as much water as it receives from its renewable water resource, resorting to mining groundwater to meet its needs.

Must the world inevitably face water shortages? (SciCentral video, Real Player)

Agriculture is globally the major user of water. Moreover, because the production of biomass requires the evaporation of large amounts of water, agriculture is essentially a consumptive user and water-efficient irrigation leaves practically no return water. In recent years, propelled by an irrigation-based green revolution, global agricultural production has increased significantly and the overall nutritional situation of the world has improved.

However, it’s becoming harder for farmers to keep up with the growing population because supplies of water for irrigation are declining around the world as underground water reserves (aquifers) become depleted faster than nature can fill them. “Groundwater overdrafting is now widespread in the crop-producing regions of central and northern China, northwest and southern India, parts of Pakistan, much of the Western United States, North Africa, the Middle East and the Arabian Peninsula,” reports Sandra Postel, director of the Global Water Policy Project in Amherst, Mass.

At a time when concern about shrinking availability of water per person hits the headlines, there is still a large number of people - over 800 million - that are not properly nourished.

Unlike many widely traded agricultural products, water is not easily transported over large distances. With some exceptions, most water questions are of a national or local nature. In the humid tropics, well endowed with water, existing nutritional problems are often caused by agronomical difficulties associated with excess humidity. In the arid and semi-arid belts of the world, many countries now facing water stress use a large part of their water in irrigated agriculture.

Sprawl reduces water supply (CBS News, new window)

In the temperate regions, highly populated and developed countries can cope with relatively small amounts of water available per capita because agriculture receives plenty of water from natural rainfall. Many of the World's cultures would find it unbelievable that we use drinking water in our toilet facilities. On average, our society uses almost 100 gallons of drinking water per person per day. Of the "drinking water" supplied by public water systems, only a small portion is actually used for drinking. As residential water consumers, we use most of our water for other purposes, such as toilet flushing, bathing, cooking, cleaning, and lawn watering.

The bottom line - To overcome the hunger problem and ensure access to food, the income of the poorest people must grow faster than the cost of food. There are few opportunities to allocate more water to agriculture; the rate of increase in irrigated land is tapering off and pressure on agriculture to release already appropriated water for other uses is growing. Water, being a limited resource, needs to be allocated to the user that yields most benefits to society.

In 1994 FAO reported that 54 of 117 countries studied over the preceding decade could not grow enough food on their own land to feed their populations using the low levels of agricultural technology available to most people. Most of these food-deficit countries could not import enough food to make up the shortfall. Food-Deficit Countries, are, by definition, these countries have a per capita gross national product (GNP) of US$1,345 or less and have had a net deficit in grain trade over the preceding five years (94-99).

In many of them, population growth is among the most rapid in the world, and most face serious constraints to increasing agricultural production. To one degree or another, these constraints affect many other developing countries as well:

• Limited agricultural land. The best agricultural land is already being cultivated. Most of the remaining potential agricultural land consists of clay or sandy soils, often on steep slopes with limited water supplies, or nutrient-poor tropical soils
• Limited water supplies. Fresh water resources are scarce, and there often are severe water shortages during dry seasons
• Poverty. Farmers often lack enough land to feed their families, let alone to produce food surpluses for sale, while their countries cannot afford to import enough food to meet people's needs
• Poor access to credit. Many farmers cannot obtain loans to bridge the gap in their incomes between harvests and must seek work as laborers or even sell off some of their land to survive
• Lack of appropriate policies. To produce more food, communities need help obtaining suitable technologies and crop varieties and developing sound agricultural strategies .

What’s clear is that unless the population explosion, cited by many scientists as our most pressing global problem, can be brought under control efforts to deal with many of the world's pollution and disease problems will never occur. There are just too many of us. Unless we bring it under control, this old planet’s “human carrying capacity” as scientists call it, will do it for us.

End of Last Section of Bio 113